Watanabe Masao
| Faculty of Engineering Mechanical and Aerospace Engineering Thermal and Fluid Systems | Professor |
Last Updated :2025/12/04
■Researcher basic information
Degree
Researchmap personal page
Home Page URL
J-Global ID
Research Keyword
Research Field
Educational Organization
- Bachelor's degree program, School of Engineering
- Master's degree program, Graduate School of Engineering
- Doctoral (PhD) degree program, Graduate School of Engineering
■Career
Career
- Apr. 2020 - Present
Hokkaido University, Division of Mechanical and Aerospace Engineering, Professor - Jun. 2011 - Mar. 2020
Hokkaido University, Division of Mechanical and Space Engineering, Professor - Jun. 2008 - May 2011
Hokkaido University, Division of Mechanical and Space Engineering, Associate Professor - Apr. 1995 - May 2008
Kyushu University, Department of Mechanical Engineering, Associate Professor
Educational Background
■Research activity information
Awards
- Oct. 2017, 一般社団法人日本機械学会, 日本機械学会流体工学部門貢献表彰
渡部 正夫 - Oct. 2014, 日本学術振興会, 科研費審査員表彰
渡部 正夫 - Aug. 2013, 日本混相流学会, 2012年度日本混相流学会 学会賞・論文賞
気泡後部トロイダル渦の抗力への寄与
城田農;佐藤文香;真田俊之;渡部正夫, Japan society, Japan - Mar. 2012, The Japan Society of Mechanical Engineers, JSME Medal for Outstanding Paper
Unified Theory Based on Parameter Scaling for Derivation of Nonlinear Wave Equations in Bubbly Liquids
Tetsuya KANAGAWA;Takeru YANO;Masao WATANABE;Shigeo FUJIKAWA
Papers
- Polydisperse stickiness and particle size on light scattering in dense colloidal suspensions: A numerical study using the binary sticky hard-sphere model
Hiroyuki Fujii, Koyata Nishikawa, Hyeonwoo Na, Kazumichi Kobayashi, Masao Watanabe
Results in Physics, 73, 108247, 108247, Elsevier BV, Jun. 2025
Scientific journal - Particle size distribution effects on the light scattering properties in non-diluted colloidal suspensions: A numerical study
Hiroyuki Fujii, Hyeonwoo Na, Jungyun Yi, Kazumichi Kobayashi, Masao Watanabe
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 135208, 135208, Elsevier BV, Aug. 2024
Scientific journal - Interference effects on light scattering properties of dense colloidal suspensions: a short review
Hiroyuki Fujii, Hyeonwoo Na, Koyata Nishikawa, Kazumichi Kobayashi, Masao Watanabe
Optical Review, 31, 3, 299, 308, Springer Science and Business Media LLC, 22 May 2024
Scientific journal, Abstract
Near-infrared spectroscopy and imaging using scattered light potentially evaluate the structural properties of the medium, like the average particle size, based on a relation between its structure and light scattering. A qualitative understanding of light scattering is crucial for developing optical imaging techniques. The scattering properties of dense colloidal suspensions have been extensively investigated using the electromagnetic theory (EMT). The colloidal suspensions are widely used in liquid tissue phantoms for optical imaging techniques and are encountered in various fields, such as the food and chemical industries. The interference between electric fields scattered by colloidal particles significantly influences the scattering properties, so-called the interference effects. Despite many efforts since the 1980s, a complete understanding of the interference effects has still not been achieved. The main reason is the complicated dependence of the interference on the optical wavelength, particle size, and so on. This paper briefly reviews numerical and theoretical studies of the interference effect based on the dependent scattering theory, one of the EMTs, and model equations. - Couette flow at high Knudsen number between wall and liquid boundaries
Kazumichi Kobayashi, Kota Aoki, Hirofumi Tabe, Hiroyuki Fujii, Toshiki Nara, Hideyoshi Takashima, Nobuyuki Oshima, Masao Watanabe
Physics of Fluids, 35, 8, AIP Publishing, 01 Aug. 2023
Scientific journal, This paper presents molecular dynamics simulations of the Couette flow of a rarefied gas between the liquid and wall boundaries and, in particular, investigates the boundary conditions for the Boltzmann equation at the liquid interface. The simulation results for various Knudsen numbers show that the slip velocity decreases at the liquid boundary and increases at the smooth wall as the Knudsen number increases, indicating that the velocity profile of the rarefied Couette flow is asymmetric. One reason for this is backscattering, in which molecules are reflected in the opposite direction to the mainstream flow, owing to molecular-scale roughness at the liquid boundary. It has also been suggested that the backscattering effect decreases when the gas density increases. This can be understood using the local Knudsen numbers near the liquid boundary. - Numerical study of light scattering and propagation in soymilk: Effects of particle size distributions, concentrations, and medium sizes
Hiroyuki Fujii, Koyata Nishikawa, Hyeonwoo Na, Yuki Inoue, Kazumichi Kobayashi, Masao Watanabe
Infrared Physics & Technology, 132, 104753, 104753, Elsevier BV, Aug. 2023
Scientific journal - Vapor condensation induced by fast-moving liquid film in the presence of noncondensable gas molecules
Kotaro Ohashi, Kazumichi Kobayashi, Hiroyuki Fujii, Masao Watanabe
International Communications in Heat and Mass Transfer, 142, 106622, 106622, Elsevier BV, Mar. 2023
Scientific journal - Modeling photoacoustic pressure generation in colloidal suspensions at different volume fractions based on a multi-scale approach
Hiroyuki Fujii, Iori Terabayashi, Kazumichi Kobayashi, Masao Watanabe
Photoacoustics, 27, 100368, 100368, Elsevier BV, Sep. 2022
Scientific journal - Wetting failure in the early stage of water drop impact on a smooth solid surface
Ryunosuke Adachi, Kazumichi Kobayashi, Hiroyuki Fujii, Toshiyuki Sanada, Masao Watanabe
Physics of Fluids, 34, 6, 062116, 062116, AIP Publishing, Jun. 2022
Scientific journal, A water drop impacting a dry solid surface can eject a thin liquid sheet, which is forced to expand on the surface to wet the solid surface. Wetting failure, which produces defects in applications based on the impact of drops, including coating, cooling, cleaning, and printing, may occur with a sufficiently large liquid-sheet velocity. However, the exact onset of wetting failure when a drop impacts the surface has yet to be determined. Therefore, we examine the dependence of rim instability immediately after liquid-sheet ejection on the static contact angle of the solid surface at the instant of water drop impact. This study is the first attempt to solve this problem and is made possible only by using an ultra-high-speed camera. We revealed that wetting failure can occur by investigating the rim instability of the liquid sheet. - Molecular dynamics simulation of evaporation coefficient of vapor molecules during steady net evaporation in binary mixture system
Hirofumi Tabe, Kazumichi Kobayashi, Hiroyuki Fujii, Masao Watanabe
International Journal of Heat and Mass Transfer, 188, 122663, 122663, Elsevier BV, Jun. 2022
Scientific journal - Molecular dynamics study of evaporation induced by locally heated argon liquid
Hirofumi Tabe, Kiryu Hiramatsu, Kazumichi Kobayashi, Hiroyuki Fujii, Masao Watanabe, Tsuyoshi Totani
Applied Thermal Engineering, 212, 118472, 118472, Elsevier BV, Apr. 2022
Scientific journal - Model equations of light scattering properties and a characteristic time of light propagation for polydisperse colloidal suspensions at different volume fractions
Hiroyuki Fujii, Moegi Ueno, Yuki Inoue, Toshiaki Aoki, Kazumichi Kobayashi, Masao Watanabe
Optics Express, 30, 3, 3538, 3538, The Optical Society, 31 Jan. 2022
Scientific journal - Numerical Study of Near-Infrared Light Propagation in Aqueous Alumina Suspensions Using the Steady-State Radiative Transfer Equation and Dependent Scattering Theory
Hiroyuki Fujii, Iori Terabayashi, Toshiaki Aoki, Yuki Inoue, Hyeonwoo Na, Kazumichi Kobayashi, Masao Watanabe
Applied Sciences, 12, 3, 1190, 1190, MDPI AG, 24 Jan. 2022
Scientific journal, Understanding light propagation in liquid phantoms, such as colloidal suspensions, involves fundamental research of near-infrared optical imaging and spectroscopy for biological tissues. Our objective is to numerically investigate light propagation in the alumina colloidal suspensions with the mean alumina particle diameter of 55 nm at the volume fraction range 1–20%. We calculated the light scattering properties using the dependent scattering theory (DST) on a length scale comparable to the optical wavelength. We calculated the steady-state radiative transfer and photon diffusion equations (RTE and PDE) using the DST results based on the finite difference method in a length scale of the mean free path. The DST calculations showed that the scattering and reduced scattering coefficients become more prominent at a higher volume fraction. The anisotropy factor is almost zero at all the volume fractions, meaning the scattering is isotropic. The comparative study of the RTE with the PDE showed that the diffusion approximation holds at the internal region with all the volume fractions and the boundary region with the volume fraction higher than 1%. Our findings suggest the usefulness of the PDE as a light propagation model for the alumina suspensions rather than the RTE, which provides accurate but complicated computation. - Mean-field kinetic theory analysis of vapor flow between evaporating and condensing interfaces in the presence of non-condensable gas molecules
Kotaro Ohashi, Kazumichi Kobayashi, Hiroyuki Fujii, Masao Watanabe
Physics of Fluids, 33, 12, 122017, 122017, AIP Publishing, Dec. 2021
Scientific journal - Numerical Modelling of Initial Photoacoustic Pressure in Colloidal Suspensions for Photoacoustic Imaging
Hiroyuki Fujii, Toshiaki Aoki, Yuki Inoue, Iori Terabayashi, Kazumichi Kobayashi, Masao Watanabe
Technical digest of 26th Microoptics Conference (MOC2021), PO-11, 164, 165, The Japan Society of Applied Physics, Sep. 2021, [Peer-reviewed]
English, International conference proceedings - Molecular dynamics study on characteristics of reflection and condensation molecules at vapor–liquid equilibrium state
Hirofumi Tabe, Kazumichi Kobayashi, Hiroyuki Fujii, Masao Watanabe
PLOS ONE, 16, 3, e0248660, e0248660, Public Library of Science (PLoS), 16 Mar. 2021, [Peer-reviewed], [Last author]
Scientific journal, The kinetic boundary condition (KBC) represents the evaporation or condensation of molecules at the vapor–liquid interface for molecular gas dynamics (MGD). When constructing the KBC, it is necessary to classify molecular motions into evaporation, condensation, and reflection in molecular-scale simulation methods. Recently, a method that involves setting the vapor boundary and liquid boundary has been used for classifying molecules. The position of the vapor boundary is related to the position where the KBC is applied in MGD analyses, whereas that of the liquid boundary has not been uniquely determined. Therefore, in this study, we conducted molecular dynamics simulations to discuss the position of the liquid boundary for the construction of KBCs. We obtained some variables that characterize molecular motions such as the positions that the molecules reached and the time they stayed in the vicinity of the interface. Based on the characteristics of the molecules found from these variables, we investigated the valid position of the liquid boundary. We also conducted an investigation on the relationship between the condensation coefficient and the molecular incident velocity from the vapor phase to the liquid phase. The dependence of the condensation coefficient on the incident velocity of molecules was confirmed, and the value of the condensation coefficient becomes small in the low-incident-velocity range. Furthermore, we found that the condensation coefficient in the non-equilibrium state shows almost the same value as that in the equilibrium state, although the corresponding velocity distribution functions of the incident velocity significantly differ from each other. - A comparative study of the delta-Eddington and Galerkin quadrature methods for highly forward scattering of photons in random media
Hiroyuki Fujii, Go Chiba, Yukio Yamada, Yoko Hoshi, Kazumichi Kobayashi, Masao Watanabe
Journal of Computational Physics, 423, 109825, 109825, Sep. 2020, [Peer-reviewed], [Last author]
English, Scientific journal - Photon transport model for dense polydisperse colloidal suspensions using the radiative transfer equation combined with the dependent scattering theory
Hiroyuki Fujii, Leung Tsang, Jiyue Zhu, Koki Nomura, Kazumichi Kobayashi, Masao Watanabe
Optics Express, The Optical Society, 10 Jul. 2020, [Peer-reviewed], [Last author]
Scientific journal - Evaporation coefficient and condensation coefficient of vapor under high gas pressure conditions
Kotaro Ohashi, Kazumichi Kobayashi, Hiroyuki Fujii, Masao Watanabe
Scientific Reports, 10, 8143, 18 May 2020, [Peer-reviewed], [Last author]
English, Scientific journal - Levitation mechanism of impacting nanodroplet on heated wall
Hirofumi Tabe, Kazumichi Kobayashi, Hisao Yaguchi, Hiroyuki Fujii, Masao Watanabe
International Journal of Thermal Sciences, 150, 106203, 106203, Elsevier BV, Apr. 2020, [Peer-reviewed]
Scientific journal - Enhancement of Gas Discharge from a Closed End Hole by Using Acoustic Wave Irradiation
Yuki FURUYA, Yuki MIZUSHIMA, Masao WATANABE, Toshiyuki SANADA
JAPANESE JOURNAL OF MULTIPHASE FLOW, 34, 1, 111, 117, The Japanese Society for Multiphase Flow, 15 Mar. 2020
Scientific journal - Analysis of interference effects on light scattering in colloidal suspensions
Koki Nomura, Hiroyuki Fujii, Kazumichi Kobayashi, Masao Watanabe, Goro Nishimura
Proceeding of the 7th Asian NIR symposium (ANS2020), 2020, AFI-0006, 12, 13, Feb. 2020, [Peer-reviewed]
English, International conference proceedings - Finite element investigation of light propagationin the human neck using the time-dependent radiative transfer theory
Shigeki Endo, Hiroyuki Fujii, Kazumichi Kobayashi, Masao Watanabe
Proceeding of the 7th Asian NIR symposium (ANS2020), 2020, NRT-0008, 60, 61, Feb. 2020, [Peer-reviewed]
English, International conference proceedings - Numerical study on light propagation in a white bread loaf
Hiroyuki Fujii, Goro Nishimura, Shigeki Endo, Koki Nomura, Kazumichi Kobayashi, Masao Watanabe
Proceeding of the 7th Asian NIR symposium (ANS2020), 2020, AFI-0007, 14, 15, Feb. 2020, [Peer-reviewed], [International Magazine]
English, International conference proceedings - Special Issue of the AJK2019, ASME-JSME-KSME Joint Fluids Engineering Conference 2019 Preface
Shinnosuke Obi, Koji Fukagata, Masaharu Kameda, Chisachi Kato, Yohei Morinishi, Yuichi Murai, Satoshi Watanabe, Masao Watanabe
JOURNAL OF FLUID SCIENCE AND TECHNOLOGY, 15, 2, 2020
English - Hidden prompt splashing by corona splashing at drop impact on a smooth dry surface
Taku Ashida, Masao Watanabe, Kazumichi Kobayashi, Hiroyuki Fujii, Toshiyuki Sanada
Physical Review Fluids, 5, 1, 011601, American Physical Society (APS), Jan. 2020, [Peer-reviewed], [Corresponding author]
English, Scientific journal - Characteristic Length and Time Scales of the Highly Forward Scattering of Photons in Random Media
Hiroyuki Fujii, Moegi Ueno, Kazumichi Kobayashi, Masao Watanabe
Applied Sciences, 10, 1, 93, Dec. 2019, [Peer-reviewed]
English, Scientific journal - Numerical treatment of highly forward scattering on radiative transfer using the delta-M approximation and Galerkin quadrature method
Hiroyuki Fujii, Go Chiba, Yukio Yamada, Yoko Hoshi, Kazumichi Kobayashi, Masao Watanabe
Proceedings of the 9th International Symposium on Radiative Transfer, RAD-19, SM05, 261, 268, Sep. 2019, [Peer-reviewed]
English, International conference proceedings - Numerical errors of light propagation in the two-dimensional human neck model using the time-dependent radiative transfer equation with renormalized phase functions
Hiroyuki Fujii, Yamada Yukio, Hoshi Yoko, Kobayashi Kazumichi, Watanabe Masao
AIP Conference Proceedings (ICNAAM2018), 2116, 450037, 1, 4, Jul. 2019, [Peer-reviewed]
English, International conference proceedings - Finite element investigation of a void region on light propagation in scattering media using the radiative transfer equation
Kosuke Tabayashi, Hiroyuki Fujii, Kazumichi Kobayashi, Masao Watanabe
AIP Conference Proceedings (ICNAAM2018), 2116, 450052, 1, 4, Jul. 2019, [Peer-reviewed]
English, International conference proceedings - Influence of a small amount of noncondensable gas on shock wave generation inside a collapsing vapor bubble
Kyohei Yamamoto, Kazumichi Kobayashi, Masao Watanabe, Hiroyuki Fujii, Misaki Kon, Hiroyuki Takahira
Physical Review Fluids, 4, 6, American Physical Society, 11 Jun. 2019
English, Scientific journal - Light propagation models of the human neck for photoacoustic imaging of thyroid cancer
Kosuke Tabayashi, Hiroyuki Fujii, Shinpei Okawa, Kazumichi Kobayashi, Yukio Yamada, Yoko Hoshi, Masao Watanabe
CMBE Proceedings (6th International Conference on Computational & Mathematical Biomedical Engineering), A5, 161, 164, May 2019, [Peer-reviewed]
English, International conference proceedings - Correction to: Influence of liquid–solid intermolecular force on levitation of impacting nanodroplet (Heat and Mass Transfer, (2019), 55, 4, (993-1003), 10.1007/s00231-018-2474-4)
Hirofumi Tabe, Kazumichi Kobayashi, Hisao Yaguchi, Hiroyuki Fujii, Masao Watanabe
Heat and Mass Transfer/Waerme- und Stoffuebertragung, 55, 4, 1005, Springer Verlag, 11 Apr. 2019
English, Scientific journal - Influence of liquid–solid intermolecular force on levitation of impacting nanodroplet
Hirofumi Tabe, Kazumichi Kobayashi, Hisao Yaguchi, Hiroyuki Fujii, Masao Watanabe
Heat and Mass Transfer, 55, 4, 993, 1003, Springer Science and Business Media LLC, Apr. 2019, [Peer-reviewed]
English, Scientific journal - A model for a gas column oscillation inside a hole by irradiating an acoustic wave
Yuki Furuya, Toshiyuki Sanada, Masao Watanabe
ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019, 5, American Society of Mechanical Engineers (ASME), 2019
English, International conference proceedings - Molecular Dynamics Study on Influence of Liquid-solid Intermolecular Force on Levitating Mechanism of Impacting Nanodroplet on Heated Wall
Hirofumi Tabe, Kazumichi Kobayashi, Hisao Yaguchi, Hiroyuki Fujii, Masao Watanabe
Surface Wettability Effects on Phase Change Phenomena(SWEP), 2019, [Peer-reviewed] - Molecular gas dynamics analysis on condensation coefficient of vapour during gas-vapour bubble collapse
Kazumichi Kobayashi, Takahiro Nagayama, Masao Watanabe, Hiroyuki Fujii, Misaki Kon
Journal of Fluid Mechanics, 856, 1045, 1063, Dec. 2018, [Peer-reviewed]
English, Scientific journal, This study investigates the influence of the condensation coefficient of vapour on the collapse of a bubble composed of condensable gas (vapour) and non-condensable gas (NC gas). We simulated vapour and NC gas flow inside a bubble based on the molecular gas dynamics analysis in order to replicate the phase change (viz., evaporation and condensation) precisely, by changing the initial number density ratio of the NC gas and vapour, the initial bubble radius and the value of the condensation coefficient. The results show that the motion of the bubble is unaffected by the value of the condensation coefficient when that value is larger than approximately 0.4. We also discuss NC gas drift at the bubble wall during the final stage of the bubble collapse and its influence on the condensation coefficient. We conclude that vapour molecules can behave as NC gas molecules when the bubble collapses, owing to the large concentration of NC gas molecules at the gas–liquid interface. That is, the condensation coefficient reaches almost zero when the bubble collapses violently. - Accurate and efficient computation of the 3D radiative transfer equation in highly forward-peaked scattering media using a renormalization approach
Hiroyuki Fujii, YukioYamad, Go Chiba, Yoko Hoshi, Kazumichi Kobayashi, Masao Watanabe
Journal of Computational Physics, 371, 591, 604, Dec. 2018, [Peer-reviewed]
English, Scientific journal - Pressure generated at the instant of impact between a liquid droplet and solid surface
Y. Tatekura, M. Watanabe, K. Kobayashi, T. Sanada
Royal Society Open Science, 5, 12, 181101, Dec. 2018, [Peer-reviewed], [Corresponding author]
English, Scientific journal - Observation of liquid infiltration process into closed-end holes by droplet train impingement
Toshiyuki SANADA, Yuki FURUYA, Shunsuke MURAKI, Masao WATANABE
Journal of Fluid Science and Technology, 13, 3, JFST0012, JFST0012, Japan Society of Mechanical Engineers, Oct. 2018, [Peer-reviewed]
English, Scientific journal - Light propagation model of titanium dioxide suspensions in water using the radiative transfer equation
Hiroyuki Fujii, Yukio Yamada, Yoko Hoshi, Shinpei Okawa, Kazumichi Kobayashi, Masao Watanabe
Reaction Kinetics, Mechanisms and Catalysis, 123, 2, 439, 453, Springer Netherlands, 01 Apr. 2018, [Peer-reviewed]
English, Scientific journal - Fine droplets generation induced by interactions between focused ultrasound and a liquid surface
Kazuya Seko, Kazumichi Kobayashi, Hiroyuki Fujii, Masao Watanabe
Japanese Journal of Multiphase Flow, 32, 1, 59, 64, Mar. 2018, [Peer-reviewed]
Japanese, Scientific journal - Influence of surface roughness of high temperature wall on levitation of impacting droplet based on molecular dynamics simulation
Hirofumi Tabe, Kazumichi Kobayashi, Hisao Yaguchi, Hiroyuki Fujii, Masao Watanabe
Surface Wettability Effects on Phase Change Phenomena (SWEP) workshop, 2018, [Peer-reviewed]
English, International conference proceedings - Numerical investigation of light and pressure propagation in biological tissue for model-based photoacoustic tomography
Kosuke Tabayashi, Hiroyuki Fujii, Kazumichi Kobayashi, Masao Watanabe
Extended Abstracts of The 9th JSME-KSME Thermal and Fluids Engineering Conference, TFEC9-1526, 1, 4, Oct. 2017, [Peer-reviewed]
English, International conference proceedings - Kinetic boundary condition in vapor-liquid two-phase system during unsteady net evaporation/condensation
Misaki Kon, Kazumichi Kobayashi, Masao Watanabe
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS, 64, 81, 92, Jul. 2017, [Peer-reviewed]
English, Scientific journal - Influence of condensation coefficient on spherical bubble collapse with evaporation and condensation
Shotaro Morikawa, Yuki Tatekura, Kazumichi Kobayashi, Hiroyuki Fujii, Masao Watanabe, Koichi Sasaki
journal of Japan Society of Fluid Mechanics, 36, 2, 105, 108, 日本流体力学会, May 2017, [Peer-reviewed]
Japanese, Scientific journal - Modeling of light propagation in the human neck for diagnoses of thyroid cancers by diffuse optical tomography
H. Fujii, Y. Yamada, K. Kobayashi, M. Watanabe, Y. Hoshi
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, 33, 5, e2826, May 2017, [Peer-reviewed]
English, Scientific journal - Observation of the liquid film on a circular plate formed by a droplet train impingement
村木駿介, 山本翔也, 真田俊之, 渡部正夫
Transactions of the JSME, 848, 17, 00047, Apr. 2017, [Peer-reviewed] - Kinetic boundary conditions for vapor-gas binary mixture
Kazumichi Kobayashi, Kiyofumi Sasaki, Misaki Kon, Hiroyuki Fujii, Masao Watanabe
MICROFLUIDICS AND NANOFLUIDICS, 21, 3, 1, 13, Mar. 2017, [Peer-reviewed]
English, Scientific journal - Molecular Dynamics Study of Droplet Impact on High-Temperature Wall
Hirofumi Tabe, Kazumichi Kobayashi, Hisao Yaguchi, Hiroyuki Fujii, Masao Watanabe
The 7th East Asia Mechanical and Aerospace Engineering Workshop, 2017, [Peer-reviewed]
English, International conference proceedings - Molecular Dynamics Simulation of the Role of the Wettability in the Droplet Impact on a High-temperature Wall
Hirofumi Tabe, Kazumichi Kobayashi, Hisao Yaguchi, Hiroyuki Fujii, Masao Watanabe
Extended Abstracts of the 9th JSME-KSME Thermal and Fluids Engineering Conference, TFEC9-1492, 2017, [Peer-reviewed]
English, International conference proceedings - Renormalization of the highly forward-peaked phase function using the double exponential formula for radiative transfer
Hiroyuki Fujii, Shinpei Okawa, Yukio Yamada, Yoko Hoshi, Masao Watanabe
JOURNAL OF MATHEMATICAL CHEMISTRY, 54, 10, 2048, 2061, Nov. 2016, [Peer-reviewed]
English, Scientific journal - Molecular dynamics study on evaporation and reflection of monatomic molecules to construct kinetic boundary condition in vapor-liquid equilibria
Kazumichi Kobayashi, Kazumasa Hori, Misaki Kon, Kiyofumi Sasaki, Masao Watanabe
HEAT AND MASS TRANSFER, 52, 9, 1851, 1859, Sep. 2016, [Peer-reviewed]
English, Scientific journal - Liquid temperature dependence of kinetic boundary condition at vapor-liquid interface
Misaki Kon, Kazumichi Kobayashi, Masao Watanabe
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 99, 317, 326, Aug. 2016, [Peer-reviewed]
English, Scientific journal - Gas compression and dissolution in closed end tubes by applying pressure (Liquid infiltration characteristics into fine structure by pressure)
SANADA Toshiyuki, NOZAKI Hiroshi, WATANABE Masao
Transactions of the JSME, 82, 838, Jun. 2016, [Peer-reviewed]
Japanese, Scientific journal - Early stage of nanodroplet impact on solid wall
Kazumichi Kobayashi, Kazuki Konno, Hisao Yaguchi, Hiroyuki Fujii, Toshiyuki Sanada, Masao Watanabe
PHYSICS OF FLUIDS, 28, 3, Mar. 2016, [Peer-reviewed]
English, Scientific journal - Near-infrared optical properties of white bread using the light propagation model
Hiroyuki Fujii, Goro Nishimura, Kiyohito Hattori, Kazumichi Kobayashi, Masao Watanabe
Proceeding of the fifth Asian NIR symposium (ANS2016), 2016, P-86, 288, 289, 2016, [Peer-reviewed]
English, International conference proceedings - Quantitative method to determine the optical properties of melons by the photon diffusion equation
Kiyohito Hattori, Goro Nishimura, Hiroyuki Fujii, Kazumichi Kobayashi, Masao Watanabe
Proceeding of the fifth Asian NIR symposium (ANS2016), 2016, O-6, 72, 73, 2016, [Peer-reviewed]
English, International conference proceedings - Normalisation Method of Highly Forward-peaked Scattering Phase Function using the Double Exponential Formula for Radiative Transfer
Hiroyuki Fujii, Shinpei Okawa, Yukio Yamada, Yoko Hoshi, Masao Watanabe
Proceedings of the International Conference of Computational Methods in Sciences and Engineering 2016 (ICCMSE-2016), 1790, 050002, 1, 4, 2016, [Peer-reviewed]
English, International conference proceedings - Numerical Study of Photon Migration in the Presence of a Void Region using the radiative Transfer and Diffusion Equations
Erina Miyakawa, Hiroyuki Fujii, Kiyohito Hattori, Yuki Tatekura, Kazumichi Kobayashi, Masao Watanabe
Proceedings of the International Conference of Computational Methods in Sciences and Engineering 2016 (ICCMSE-2016), 1790, 050003, 2016, [Peer-reviewed]
English, International conference proceedings - Molecular Dynamics Simulation on Kinetic Boundary Conditions of Gas-Vapor Binary Mixture
Kazumichi Kobayashi, Kiyofumi Sasaki, Misaki Kon, Hiroyuki Fujii, Masao Watanabe
30TH INTERNATIONAL SYMPOSIUM ON RAREFIED GAS DYNAMICS (RGD 30), 1786, 110002, 2016, [Peer-reviewed]
English, International conference proceedings - Molecular Simulation of Evaporation Mass Flux during Net Evaporation/Condensation
Misaki Kon, Kazumichi Kobayashi, Masao Watanabe
30TH INTERNATIONAL SYMPOSIUM ON RAREFIED GAS DYNAMICS (RGD 30), 1786, 110001, 2016, [Peer-reviewed]
English, International conference proceedings - Numerical modeling of photon migration in human neck based on the radiative transport equation
Hiroyuki Fujii, Shinpei Okawa, Ken Nadamoto, Eiji Okada, Yukio Yamada, Yoko Hoshi, Masao Watanabe
Journal of Applied Nonlinear Dynamics, 5, 1, 117, 125, L and H Scientific Publishing, LLC, 2016, [Peer-reviewed]
English, Scientific journal - Estimation of Evaporation Mass Flux at Vapor-Liquid Interface during Nonequilibrium Evaporation/condensation
Kazumichi Kobayashi, Kazumasa Hori, Misaki Kon, Kiyofumi Sasaki, Masao Watanabe
JAPANESE JOURNAL OF MULTIPHASE FLOW, 29, 5, 493, 500, THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, Nov. 2015, [Peer-reviewed]
Japanese, Scientific journal, The aim of this study is to confirm the existence of a spontaneous evaporation molecular mass flux which takes a constant value independent of the degree of net evaporation/condensation. We carried out the numerical simulation based on the mean field kinetic theory during net evaporation/condensation and estimated the evaporation and reflection molecular mass fluxes by using a pair of boundaries. The simulation results showed that the reflection molecular mass flux varies with the increase of the degree of nonequilibrium, and the evaporation molecular mass flux takes a constant value during net evaporation and condensation. - How do bubbles reduce the speed of sound in a bubbly liquid in a duct?
Junya Kawahara, Masao Watanabe, Kazumichi Kobayashi
Mechanical Engineering Letters, 1, 115-00464-15-00464, Oct. 2015, [Peer-reviewed]
English, Scientific journal - 低圧力環境下での高速液滴衝突により発生する液膜流れ
KATO MASAYA, WATANABE MASAO, KOBAYASHI KAZUMICHI, SANADA TOSHIYUKI
混相流, 28/29, 5/1, 531, 537, 15 Mar. 2015
Japanese - 22aAK-12 Effect of nonequilibrium velocity distribution function to vapor flows
Kon M., Kobayashi K., Watanabe M.
Meeting Abstracts of the Physical Society of Japan, 70, 2975, 2975, The Physical Society of Japan (JPS), 2015
Japanese - A coupling model of the radiative transport equation for calculating photon migration in biological tissue
Hiroyuki Fujii, Shinpei Okawa, Yukio Yamada, Yoko Hoshi, Masao Watanabe
Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 9792, SPIE, 2015, [Peer-reviewed]
English, International conference proceedings - Numerical study of light propagation in agricultural products for non-destructive assessment of food quality
Kiyohito Hattori, Hiroyuki Fujii, Yuki Tatekura, Kazumichi Kobayashi, Masao Watanabe
Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 9792, SPIE, 2015, [Peer-reviewed]
English, International conference proceedings - Numerical modeling of photon migration in the cerebral cortex of the living rat using the radiative transport equation
Hiroyuki Fujii, Shinpei Okawa, Ken Nadamoto, Eiji Okada, Yukio Yamada, Yoko Hoshi, Masao Watanabe
Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 9333, SPIE, 2015, [Peer-reviewed]
English, International conference proceedings - Numerical modeling of photon migration in the cerebral cortex of the living rat using the radiative transport equation
Hiroyuki Fujii, Shinpei Okawa, Ken Nadamoto, Eiji Okada, Yukio Yamada, Yoko Hoshi, Masao Watanabe
BIOMEDICAL APPLICATIONS OF LIGHT SCATTERING IX, 9333, 933313, 1, 6, 2015, [Peer-reviewed]
English, International conference proceedings - A coupling model of the radiative transport equation for calculating photon migration in biological tissue
Hiroyuki Fujii, Shinpei Okawa, Yukio Yamada, Yoko Hoshi, Masao Watanabe
BIOPHOTONICS JAPAN 2015, 9792, 979214, 1, 5, 2015, [Peer-reviewed]
English, International conference proceedings - Numerical study of light propagation in agricultural products for non-destructive assessment of food quality
Kiyohito Hattori, Hiroyuki Fujii, Yuki Tatekura, Kazumichi Kobayashi, Masao Watanabe
BIOPHOTONICS JAPAN 2015, 9792, 97921A, 2015, [Peer-reviewed]
English, International conference proceedings - Numerical simulation of bubble collapse and the transfer of vapor and noncondensable gas through the bubble interface using the ghost fluid method
Y. Jinbo, K. Kobayashi, M. Watanabe, H. Takahira
9TH INTERNATIONAL SYMPOSIUM ON CAVITATION (CAV2015), 656, 1, 5, 2015, [Peer-reviewed]
English, International conference proceedings - Photoresist and Thin Metal Film Removal by Steam and Water Mixed Spray
Toshiyuki Sanada, Masao Watanabe
JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY, 28, 2, 289, 292, 2015, [Peer-reviewed]
English, Scientific journal - Observation of Water-Droplet Impacts with Velocities of O(10 m/s) and Subsequent Flow Field
Y. Tatekura, T. Fujikawa, Y. Jinbo, T. Sanada, K. Kobayashi, M. Watanabe
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY, 4, 9, N117, N123, 2015, [Peer-reviewed]
English, Scientific journal - Study on Pressure Wave Propagation in a Liquid Containing Spherical Bubbles in a Rectangular Duct
Junya Kawahara, Masao Watanabe, Kazumichi Kobayashi
9TH INTERNATIONAL SYMPOSIUM ON CAVITATION (CAV2015), 656, 1, 5, 2015, [Peer-reviewed]
English, International conference proceedings - Method of determining kinetic boundary conditions in net evaporation/condensation
Misaki Kon, Kazumichi Kobayashi, Masao Watanabe
PHYSICS OF FLUIDS, 26, 7, 072003, Jul. 2014, [Peer-reviewed]
English, Scientific journal - Molecular Dynamics Simulation on Evaporation Molecules in a Vapor-Liquid Equilibrium State
Kazumichi Kobayashi, Kazumasa Hori, Hisao Yaguchi, Masao Watanabe
PROCEEDINGS OF THE 29TH INTERNATIONAL SYMPOSIUM ON RAREFIED GAS DYNAMICS, 1628, 404, 410, 2014, [Peer-reviewed]
English, International conference proceedings - Numerical Analysis of Kinetic Boundary Conditions at Net Evaporation/condensation Interfaces in Various Liquid Temperatures Based on Mean-field Kinetic Theory
Misaki Kon, Kazumichi Kobayashi, Masao Watanabe
PROCEEDINGS OF THE 29TH INTERNATIONAL SYMPOSIUM ON RAREFIED GAS DYNAMICS, 1628, 398, 403, 2014, [Peer-reviewed]
English, International conference proceedings - Effect of Surrounding Gas Species of Two Fluid Jet Method for Surface Cleaning
SANADA TOSHIYUKI, WATANABE MASAO
エアロゾル研究, 29, 4, 236-240 (J-STAGE), 2014
Japanese - Analysis of Discrete Model of Spherical Bubbles with Interaction : Acoustic Characteristics of Bubbly Liquids (Mathematical theory, modeling, and applications of nonlinear wave research)
KAWAHARA Junya, KOBAYASHI Kazumichi, WATANABE Masao
RIMS Kokyuroku, 1847, 10, 15, 京都大学, Aug. 2013
Japanese - Evaporation and Condensation Coefficients of Methanol at Room Temperature, and Consideration of Kinetic Boundary Condition
KOBAYASHI KAZUMICHI, MORI SHINGO, WATANABE YUSUKE, WATANABE MASAO, FUJIKAWA SHIGEO
熱物性, 27, 1, 9, 14, JAPAN SOCIETY OF THERMOPHYSICAL PROPERTIES, 28 Feb. 2013
Japanese, The growth rate of a liquid film formed on a shock-tube endwall due to condensation of methanol vapor behind a shock wave reflected at the endwall is measured by an optical interferometer at room temperature, and it is analyzed with the aid of molecular gas dynamics in order to deduce evaporation and condensation coefficients. The measurements are done in the region of 1 ≤σ / ρ*<1.3, where σ / ρ* is nonequilibrium degree. The condensation coefficient is almost the same value as the evaporation coefficient (=0.86) in 1 ≤σ / ρ* <1.05 and decreases to the smaller values than the evaporation coefficient in σ / ρ*＞1.05, and the kinetic boundary condition is valid in 1 ≤σ / ρ*<1.05. - Nonlinear Wave Propagation in Bubbly Liquids
T. Yano, T. Kanagawa, M. Watanabe, S. Fujikawa
Bubble Dynamics and Shock Waves, 107, 140, Springer Berlin Heidelberg, 2013
In book - Molecular Dynamics Study of Nano-scale Liquid-gas Interface Inspired by Fuel Cell Catalyst Layer
Youngmin Kim, Hisao Yaguchi, Nobuyuki Oshima, Masao Watanabe, Kazumichi Kobayashi
ASME 2013 11th International Conference on Nanochannels, 2013, [Peer-reviewed] - 蒸発・凝縮をともなう非線形共鳴音波
INABA MASASHI, YANO TAKERU, KOBAYASHI KAZUMICHI, WATANABE MASAO
ながれ, 31, 6, 487, 490, 日本流体力学会, 25 Dec. 2012
Japanese - 水蒸気と水の混合噴流による表面薄膜はく離(アルミニウム蒸着膜のはく離特性と表面温度変化の影響)
真田俊之, 橋本健太郎, 林田充司, 小林一道, 渡部正夫
混相流, 26, 2, 172, 177, THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, 15 Jun. 2012
Japanese, We have been developing a novel surface cleaning technique using steam and water mixed spray. Our technique shows great efficiency in removing thin surface film such as photo-resist film. However, the film-removal mechanism has not been clarified yet. One possible film-removal mechanism is the local heat expansion due to the difference of coefficients of linear expansion between film and substrate. In this study, we studied the removal characteristics of deposited aluminum film on a glass surface by spraying steam-water or air-water mixed spray. The surface temperature changes caused by the spray were carefully measured. We found that the steam and water mixed spray that increases the surface temperature can remove the film while the air and water mixed spray cannot. These results indicate that the difference of coefficients of linear expansion between film and substrate may not be the dominant factor in the film removal by the steam and water mixed spray. - 固体表面に衝突する単一液滴変形過程の観察(液滴物性,対象物表面粗さ及び周囲気体圧力の影響)
櫻井泰貴, 小林一道, 藤川俊秀, 真田俊之, 渡部正夫
混相流, 26, 2, 164, 171, THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, 15 Jun. 2012
Japanese, In the cleaning processes of manufacturing semiconductor devices, two-fluid spray cleaning technique is widely used: however, the detailed cleaning mechanism has not been clarified yet. In this study, we focus our attention to the elementary process of this cleaning technique, i.e. a single droplet impact on a solid surface. We experimentally observe impact of single droplet on a rigid solid surface with the use of high-speed photography, and we discuss the deformation of the droplet. Especially we focus on the effects of surfaces tension, surface roughness and surrounding pressure. Water droplets always create lamella during spreading after the impact on a smooth surface in the atmospheric pressure condition. Either decrease of the surface tension or increase of the surface roughness causes droplet splash. However, decrease of the surrounding gas pressure makes droplets always create lamella even in the cases with low surface tension and rough surfaces. - Thin Film Removal by Steam and Water Mixed Spray : Removal Characteristic of Deposited Aluminum Film and Effects of Surface Temperature Change
SANADA Toshiyuki, HASHIMOTO Kentaro, HAYASHIDA Atsushi, KOBAYASHI Kazumichi, WATANABE Masao
JAPANESE JOURNAL OF MULTIPHASE FLOW, 26, 2, 172, 177, THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, 15 Jun. 2012
Japanese, We have been developing a novel surface cleaning technique using steam and water mixed spray. Our technique shows great efficiency in removing thin surface film such as photo-resist film. However, the film-removal mechanism has not been clarified yet. One possible film-removal mechanism is the local heat expansion due to the difference of coefficients of linear expansion between film and substrate. In this study, we studied the removal characteristics of deposited aluminum film on a glass surface by spraying steam-water or air-water mixed spray. The surface temperature changes caused by the spray were carefully measured. We found that the steam and water mixed spray that increases the surface temperature can remove the film while the air and water mixed spray cannot. These results indicate that the difference of coefficients of linear expansion between film and substrate may not be the dominant factor in the film removal by the steam and water mixed spray. - Observation of Deformation of Single Droplet Impact on Solid Surface : Effects of Liquid Properties, Surface Roughness and Surrounding Gas Pressure
SAKURAI Yasuki, KOBAYASHI Kazumichi, FUJIKAWA Toshihide, SANADA Toshiyuki, WATANABE Masao
JAPANESE JOURNAL OF MULTIPHASE FLOW, 26, 2, 164, 171, THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, Jun. 2012, [Peer-reviewed]
Japanese, Scientific journal, In the cleaning processes of manufacturing semiconductor devices, two-fluid spray cleaning technique is widely used: however, the detailed cleaning mechanism has not been clarified yet. In this study, we focus our attention to the elementary process of this cleaning technique, i.e. a single droplet impact on a solid surface. We experimentally observe impact of single droplet on a rigid solid surface with the use of high-speed photography, and we discuss the deformation of the droplet. Especially we focus on the effects of surfaces tension, surface roughness and surrounding pressure. Water droplets always create lamella during spreading after the impact on a smooth surface in the atmospheric pressure condition. Either decrease of the surface tension or increase of the surface roughness causes droplet splash. However, decrease of the surrounding gas pressure makes droplets always create lamella even in the cases with low surface tension and rough surfaces. - Linear theory of sound waves with evaporation and condensation
Masashi Inaba, Takeru Yano, Masao Watanabe
FLUID DYNAMICS RESEARCH, 44, 2, Apr. 2012, [Peer-reviewed]
English, Scientific journal - NONLINEAR PROPAGATION OF SOUND BEAM IN NONUNIFORM BUBBLY LIQUIDS
Tetsuya Kanagawa, Takeru Yano, Junya Kawahara, Kazumichi Kobayashi, Masao Watanabe, Shigeo Fujikawa
FLUID MEASUREMENTS AND INSTRUMENTATION CAVITATION AND MULTIPHASE FLOW ADVANCES IN FLUIDS ENGINEERING EDUCATION MICROFLUIDICS, VOL 2, 237, 241, 2012, [Peer-reviewed]
English, International conference proceedings - ULTRASOUND BEAM RADIATED FROM CIRCULAR PISTON IN BUBBLY LIQUIDS: NONLINEAR ANALYSIS FOR ENVELOPE OF SHORT WAVES WITH DIFFRACTION EFFECT
Junya Kawahara, Tetsuya Kanagawa, Takeru Yano, Kazumichi Kobayashi, Masao Watanabe, Shigeo Fujikawa
FLUID MEASUREMENTS AND INSTRUMENTATION CAVITATION AND MULTIPHASE FLOW ADVANCES IN FLUIDS ENGINEERING EDUCATION MICROFLUIDICS, VOL 2, 251, 256, 2012, [Peer-reviewed]
English, International conference proceedings - Observation of Deformation of Single Droplet Impact on Solid Surface (Effects of Liquid Properties, Surface Roughness and Surrounding Gas Pressure)
Sakurai, Y, Kobayashi, K, Fujikawa, T, Sanada, T, Watanabe,M
Japanese J. Multiphase Flow, 98, 6, 515, 521, THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, 2012, [Peer-reviewed]
Japanese, In the cleaning processes of manufacturing semiconductor devices, two-fluid spray cleaning technique is widely used: however, the detailed cleaning mechanism has not been clarified yet. In this study, we focus our attention to the elementary process of this cleaning technique, i.e. a single droplet impact on a solid surface. We experimentally observe impact of single droplet on a rigid solid surface with the use of high-speed photography, and we discuss the deformation of the droplet. Especially we focus on the effects of surfaces tension, surface roughness and surrounding pressure. Water droplets always create lamella during spreading after the impact on a smooth surface in the atmospheric pressure condition. Either decrease of the surface tension or increase of the surface roughness causes droplet splash. However, decrease of the surrounding gas pressure makes droplets always create lamella even in the cases with low surface tension and rough surfaces. - Order Estimation of Physical Processes in Dynamics of Steam-Water Mixed Spray Cleaning Technique
Masao Watanabe, Toshiyuki Sanada, Takashi Mashiko, Atsushi Hayashida
ULTRA CLEAN PROCESSING OF SEMICONDUCTOR SURFACES X, 187, 141, +, 2012, [Peer-reviewed]
English, International conference proceedings - Measurement of adhesion force of resist to wafer by using SAICAS: Characteristics of lift-off of resist by steam-water mixed spray
Takashi Mashiko, Toshiyuki Sanada, Hideo Horibe, Itsuo Nishiyama, Masao Watanabe, Atsushi Hayashida
ULTRA CLEAN PROCESSING OF SEMICONDUCTOR SURFACES X, 187, 85, +, 2012, [Peer-reviewed]
English, International conference proceedings - Derivation of Nonlinear Wave Equations for Ultrasound Beam in Nonuniform Bubbly Liquids
Tetsuya Kanagawa, Takeru Yano, Junya Kawahara, Kazumichi Kobayashi, Masao Watanabe, Shigeo Fujikawa
NONLINEAR ACOUSTICS: STATE-OF-THE-ART AND PERSPECTIVES (ISNA 19), 1474, 144, 147, 2012, [Peer-reviewed]
English, International conference proceedings - Resonant Gas Oscillation with Evaporation and Condensation
Masashi Inaba, Takeru Yano, Masao Watanabe, Kazumichi Kobayashi, Shigeo Fujikawa
NONLINEAR ACOUSTICS: STATE-OF-THE-ART AND PERSPECTIVES (ISNA 19), 1474, 80, 83, 2012, [Peer-reviewed]
English, International conference proceedings - Numerical Analysis of Vapor-Liquid Two-Phase System Based on the Enskog-Vlasov Equation
Kazumichi Kobayashi, Kotaro Ohashi, Masao Watanabe
28TH INTERNATIONAL SYMPOSIUM ON RAREFIED GAS DYNAMICS 2012, VOLS. 1 AND 2, 1501, 1145, 1151, 2012, [Peer-reviewed]
English, International conference proceedings - Nonlinear Resonant Gas Oscillation Accompanied with Evaporation and Condensation
Masashi Inaba, Takeru Yano, Kazumichi Kobayashi, Masao Watanabe
28TH INTERNATIONAL SYMPOSIUM ON RAREFIED GAS DYNAMICS 2012, VOLS. 1 AND 2, 1501, 53, 58, 2012, [Peer-reviewed]
English, International conference proceedings - ジェット洗浄技術の最前線 水蒸気と水の混合噴流による洗浄技術
真田俊之, 渡部正夫, 関映子, 林田充司
砥粒加工学会誌, 55, 11, 640-643, 643, 砥粒加工学会, 01 Nov. 2011
Japanese - A cleaning technique by steam and water mixed spray
SANADA Toshiyuki, WATANABE Masao, SEKI Akiko, HAYASHIDA Atsushi
砥粒加工学会誌 = Journal of the Japan Society of Grinding Engineers, 55, 11, 640, 643, 砥粒加工学会, 01 Nov. 2011
Japanese - Nonlinear Wave Equations for Pressure Wave Propagation in Liquids Containing Gas Bubbles ( Comparison between Two-Fluid Model and Mixture Model )
Tetsuya Kanagawa, Masao Watanabe, Takeru Yano, Shigeo Fujikawa
Journal of Fluid Science and Technology, 6, 6, 838, 850, The Japan Society of Mechanical Engineers, Aug. 2011, [Peer-reviewed]
English, Scientific journal, Based on the unified theory by the present authors (Kanagawa et al., J. Fluid Sci. Tech., 5, 2010), the Korteweg-de Vries-Burgers (KdVB) equation and the nonlinear Schrödinger (NLS) equation with an attenuation term for weakly nonlinear waves in bubbly liquids are re-derived from a system of bubble-liquid mixture model equations composed of the conservation equations of mass and momentum, the Keller equation for bubble dynamics, and supplementary equations. We show that the re-derived KdVB equation and NLS equation are essentially the same as those derived from a system of two-fluid model equations except for the coefficients of nonlinear, dissipation, and dispersion terms. The differences in these coefficients are studied in detail, and we find that for the case of KdVB equation, the mixture model is valid only for sufficiently small initial void fractions. On the other hand, for the case of NLS equation, the range of validity of the mixture model depends on not only the initial void fraction but also the wavenumber concerned. - 気泡後部トロイダル渦の抗力への寄与
城田農, 佐藤文香, 真田俊之, 渡部正夫
混相流, 24, 5, 531, 537, THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, 15 Mar. 2011
Japanese, Droplet impacts on solid surfaces are key elements in technical applications, such as semiconductor cleaning, rapid spray cooling and ink-jet printing. There exist varieties of physical parameters proposed that control the droplet impact although they are not thoroughly explored; hence, dynamics of the droplet after the impact are yet fully understood. In this study, we experimentally observed the high-speed droplet impact on acrylic surfaces in a vacuum chamber with a high-speed photography, in order to clarify the effects of both the ambient gas pressure around the droplet and the impact velocity. The results show that the splash does not occur under the reduced ambient gas pressure even when the impact velocity becomes much higher than in the conventional experiments, in the range of the present experimental conditions. - Experimental Estimate of Physical Actions of Steam-Water Mixer Spray : Dry-Etch Residue Removal, Resist Lift-Off, and Metal Erosion
MASHIKO Takashi, SANADA Toshiyuki, HASHIMOTO Kentaro, HORIBE Hideo, HAYASHIDA Atsushi, WATANABE Masao
Japanese journal of multiphase flow, 24, 5, 703, 709, 日本混相流学会, 15 Mar. 2011
Japanese - Contribution of a Toroidal Vortex behind a Bubble to Drag
SHIROTA Minori, SATO Ayaka, SANADA Toshiyuki, WATANABE Masao
Japanese journal of multiphase flow, 24, 5, 531, 537, THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, 15 Mar. 2011
Japanese, Droplet impacts on solid surfaces are key elements in technical applications, such as semiconductor cleaning, rapid spray cooling and ink-jet printing. There exist varieties of physical parameters proposed that control the droplet impact although they are not thoroughly explored; hence, dynamics of the droplet after the impact are yet fully understood. In this study, we experimentally observed the high-speed droplet impact on acrylic surfaces in a vacuum chamber with a high-speed photography, in order to clarify the effects of both the ambient gas pressure around the droplet and the impact velocity. The results show that the splash does not occur under the reduced ambient gas pressure even when the impact velocity becomes much higher than in the conventional experiments, in the range of the present experimental conditions. - 微小液滴・微小気泡・界面張力[3‐1]ナノ液滴と蒸気の一成分気液二相系における平衡条件の検討
YAGUCHI HISAO, FUJIKAWA SHIGEO, YANO TAKERU, WATANABE MASAO
アンサンブル, 13, 1, 7, 11, 分子シミュレーション研究会, 31 Jan. 2011
Japanese - Nonlinear Wave Equation for Ultrasound Beam in Nonuniform Bubbly Liquids
KANAGAWA Tetsuya, YANO Takeru, WATANABE Masao, FUJIKAWA Shigeo
JFST, 6, 2, 279, 290, The Japan Society of Mechanical Engineers, 2011
English, In our previous paper (Kanagawa et al., J. Fluid Sci. Tech., 5, 2010), we have proposed a systematic method for derivation of various types of nonlinear wave equations for plane waves in bubbly liquids. The method makes use of an asymptotic expansion with multiple scales in terms of a small wave amplitude as an expansion parameter and a set of scaling relations of physical parameters, based on basic equations of two-fluid model of bubbly flows. In this paper, we extend the method so as to handle a weakly diffracted ultrasound beam in a quiescent liquid containing a number of spherical gas bubbles distributed with a weak nonuniformity. Because of the high expandability of the original method, the extension can be accomplished by adding a scaling relation of the diameter of the beam to the original set of scaling relations. As a result, we derive a generalized Khokhlov—Zabolotskaya—Kuznetsov (KZK) equation [or a generalized Kadomtsev—Petviashvili (KP) equation] for a long wave and low frequency case. - 8I-11 Material transport and tissue development in engineered cartilage model culture under cyclic compression
SAWAE Yoshinori, WATANABE Masao, OMATA Seiji, MURAKAMI Teruo
The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME, 2010, 0, 181, 182, The Japan Society of Mechanical Engineers, 2011, [Peer-reviewed]
Japanese - High-Speed Droplet Impact as an Elementary Process of Physical Cleaning
T. Fujikawa, Y. Tatekura, K. Kobayashi, T. Sanada, A. Hayashida, M. Watanabe
SEMICONDUCTOR CLEANING SCIENCE AND TECHNOLOGY 12 (SCST 12), 41, 5, 67, 74, 2011
English, International conference proceedings - Modeling of bouncing of a single clean bubble on a free surface
A. Sato, M. Shirota, T. Sanada, M. Watanabe
PHYSICS OF FLUIDS, 23, 1, 013307, Jan. 2011, [Peer-reviewed]
English, Scientific journal - 水蒸気と水の混合噴流による表面洗浄技術 物理力による表面薄膜剥離
MASHIKO TAKASHI, SANADA TOSHIYUKI, WATANABE MASAO, HAYASHIDA ATSUSHI, SEKI AKIKO
クリーンテクノロジー, 20, 8, 65, 69, 10 Aug. 2010
Japanese - 気泡流中の弱非線形波動 (非線形波動現象の数理と応用)
金川 哲也, 矢野 猛, 渡部 正夫, 藤川 重雄
数理解析研究所講究録, 1701, 40, 46, 京都大学, Aug. 2010
Japanese - Unified Theory Based on Parameter Scaling for Derivation of Nonlinear Wave Equations in Bubbly Liquids
Tetsuya KANAGAW, Takeru YANO, Masao WATANABE, Shigeo FUJIKAWA
Journal of Fluid Science and Technology, 5, 3, 351, 369, The Japan Society of Mechanical Engineers, Jul. 2010, [Peer-reviewed]
English, Scientific journal, We propose a systematic derivation method of the Korteweg-de Vries-Burgers (KdVB) equation and nonlinear Schrödinger (NLS) equation for nonlinear waves in bubbly liquids on the basis of appropriate choices of scaling relations of physical parameters. The basic equations are composed of a set of conservation equations for mass and momentum and the equation of bubble dynamics in a two-fluid model. The scaling of parameters is related to the wavelength, frequency, propagation speed, and amplitude of waves concerned. With the help of the method of multiple scales, appropriate choices of the parameter scaling allow us to derive various nonlinear wave equations systematically from a set of basic equations. The result shows that the one-dimensional nonlinear propagation of a long wave with a low frequency is described by the KdVB equation, and that of an envelope of a carrier wave with a high frequency by the NLS equation. Thus, we establish a unified theory of derivation of nonlinear wave equations in bubbly liquids. - The Sound Wave Method for Measurement of Evaporation Coefficient
Shigeto NAKAMURA, Takeru YANO, Masao WATANABE, Shigeo FUJIKAWA
Journal of Fluid Science and Technology, 5, 1, 26, 34, The Japan Society of Mechanical Engineers, Feb. 2010, [Peer-reviewed]
English, Scientific journal, A new method for measurement of evaporation coefficient using sound resonance experiment is proposed on the basis of a theory of molecular gas dynamics, by which the evaporation coefficient is expressed as a function of the amplitude of standing sound wave between a planar sound source and a vapor-liquid interface facing against it. To demonstrate the applicability of this method, we carried out test experiments under the condition of neither evaporation nor condensation for several initial pressures, 30, 50, 80 and 101 kPa, at room temperature. In the experiments, we measure the amplitude of standing wave with a resonant frequency generated in a cylindrical space filled with air and closed by liquid water. We utilize the second harmonics component excited by the nonlinearity of sound to determine the evaporation coefficient, thereby eliminating the electromagnetic noises from measured signals. We find that the amplitude of the second harmonics at sound resonance decreases with the decrease in the initial pressure. - Single Rising Bubble Motion in Aqueous Solution of Electrolyte
Ayaka SATO, Masumi AOKI, Masao WATANABE
Journal of Fluid Science and Technology, 5, 1, 14, 25, The Japan Society of Mechanical Engineers, Feb. 2010, [Peer-reviewed]
English, Scientific journal, Effects of electrolytes on bubble coalescence are investigated experimentally from fluid dynamic point of view. Collisions of a bubble with free surface in two kinds of liquids, namely, ultrapure water and sodium chloride solution, are observed using a high speed camera. It is found that the repetitive number of bubble bounces on a free surface in electrolyte solution is larger than that in ultrapure water when the equivalent bubble radii are the same. This result qualitatively shows that electrolyte works to prevent bubbles from coalescing. It is also revealed that the bubbles can coalesce if their Weber numbers, which are based on the radius of curvature of the front side of the bubble and the approach velocity just before the collision with the free surface, are less than a critical Weber number. Furthermore, the critical Weber number decreases with the increase in the concentration of the electrolyte solutions despite the fluid dynamic characteristics, such as bubble rise velocity and bubble shape, are not affected by the addition of the electrolytes. It is concluded that Weber number is the most important parameter to specify the effects of electrolytes on bubble coalescence. - Chemical-free cleaning process, steam and water mixed spray
SANADA TOSHIYUKI, WATANABE MASAO, MASHIKO TAKASHI, HAYASHIDA ATSUSHI, KOMANO HIDEO
空気清浄, 47, 5, 31, 36, 日本空気清浄協会, 31 Jan. 2010
Japanese - S0507-1-2 Shock-Tube-Deduced Condensation Coefficients of Water and Methanol Vapors near Equilibrium States : Boltzmann-Equation-Assisted Data Analysis
MOURI Shingo, OGASAWARA Toshiki, YAGUCHI Hisao, WATANABE Masao, FUJIKAWA Shigeo
The proceedings of the JSME annual meeting, 2010, 239, 240, The Japan Society of Mechanical Engineers, 2010
Japanese, The condensation coefficients of water and methanol, i.e., the ratios of condensation mass flux of vapor molecules to their mass flux colliding on the interface, are evaluated by combining the experiment conducted by a shock tube and the numerical simulation of Gaussian-BGK Boltzmann equation applicable to polyatomic gases. Film condensation occurs on the endwall of vapor filled shock-tube, when a shock wave is reflected at the endwall and the vapor eventually becomes supersaturated there. The formed liquid film grows with the lapse of time. The time evolution in thickness of the liquid film is measured by an optical interferometer, and thereby the growth rate of the film is obtained. The rate is incorporated into the kinetic boundary condition at the interface for the Gaussian-BGK Boltzmann equation, the solution of which is in consequence obtained uniquely. The condensation coefficients in nearequilibrium states for water and methanol are found to be close to those evaluated by molecular dynamics simulations at equilibrium states. - S0507-1-1 Nonequilibrium Molecular Dynamics Simulation of Evaporation and Condensation of Nanodroplet
YAGUCHI Hisao, YANO Takeru, WATAnABE Masao, FUJIKAWA Shigeo
The proceedings of the JSME annual meeting, 2010, 237, 238, The Japan Society of Mechanical Engineers, 2010
Japanese, Nonequilibrium molecular dynamics simulation is carried out to study weak condensation of argon vapor into its nanodroplet. Temperature of the nanodroplet is kept at 90 K by using the velocity scaling method. The nanodroplet grows steadily ranging from about 3.3 to 3.4 nm in the radius R_m which is defined as the radius of the center of transition layer in density profile. The mass fluxes at the vapor-nanodroplet interface are investigated and condensation coefficient of the nanodroplet is successfully determined. As a result, the condensation coefficient is almost equal to the evaporation coefficient obtained by our previous study. The rate of change of R_m can be predicted by the mass fluxes and evaporation/condensation coefficients within about 16 percent error. - Molecular Dynamics Study of Vapor-liquid Equilibrium Condition for Nanodroplet
Hisao Yaguchi, Takeru Yano, Masao Watanabe, Shigeo Fujikawa
Proceedings of 7th International Conference on Multiphase Flow, 2010, [Peer-reviewed] - Nonlinear wave equations for pressure wave propagation in liquids containing gas bubbles (comparison between two-fluid model and mixture model)
Tetsuya Kanagawa, Masao Watanabe, Takeru Yano, Shigeo Fujikawa
Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 76, 771, 1802, 1810, Japan Society of Mechanical Engineers, 2010
Japanese, Scientific journal - Nonlinear wave equations for pressure wave propagation in liquids containing gas bubbles (comparison between two-fluid model and mixture model)
Tetsuya Kanagawa, Masao Watanabe, Takeru Yano, Shigeo Fujikawa
Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 76, 771, 1802, 1810, Japan Society of Mechanical Engineers, 2010
Japanese, Scientific journal - Effects of Electrolytes on Bubble Coalescence
Ayaka SATO, Masumi AOKI, Masao WATANABE
Progress in Multiphase Flow Research, 4, 103, 110, THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, Dec. 2009, [Peer-reviewed]
Japanese, Scientific journal, Effects of electrolytes on bubble coalescence are investigated experimentally. Collisions of bubbles with free surface of three kinds of liquids, namely, super purified water, NaCl solution and KCl solution, are observed by using a high speed camera. It is found that the numbers of bounces on a free surface in electrolyte solution are larger than those in super purified water with the same equivalent bubble radius. This result qualitatively indicates that electrolyte works to prevent bubbles from coalescing. It is also revealed that a bubble can coalesce if the Weber number, which is based on radius of curvature of fore side of the bubble and approach velocity just before collision with free surface, is less than a critical value. The decrease of the critical Weber number, which corresponds to the inhibition of the coalescence, is observed with the increase in the concentration of the electrolyte solutions. - Motion and coalescence of a pair of bubbles rising side by side
Toshiyuki Sanada, Ayaka Sato, Minori Shirota, Masao Watanabe
CHEMICAL ENGINEERING SCIENCE, 64, 11, 2659, 2671, Jun. 2009, [Peer-reviewed]
English, Scientific journal - Removal of post-dry etch residue using ultra low environmental load technique
A. Hayashida, A. Seki, T. Mashiko, T. Sanada, M. Watanabe
ECS Transactions, 25, 5, 249, 256, Electrochemical Society Inc., 2009
English, International conference proceedings - J0201-1-6 Acoustic Characteristics of Ultrasound Propagating in Liquid Containing Lipid Bubbles
IMAI Ryosuke, NAKAGAWA Hiroya, SAKURAI Kousuke, WATANABE Masao, FUJIKAWA Shigeo
The proceedings of the JSME annual meeting, 2009, 107, 108, The Japan Society of Mechanical Engineers, 2009
Japanese, In the field of medical engineering, the application of bubbles of nanometer size to Drug Delivery System (DDS) has attracted great attention as the administration of next generation. DDS with bubbles is expected to be a noninvasive clinical treatment. As the transport carrier of DDS, there exists bubble encapsulated in a lipid bilayer, generally called as a lipid bubble. However, dynamic properties of these lipid bubbles are not yet made clear. In this study, acoustic characteristics of lipid bubbles are experimentally investigated. The resonant frequencies of lipid bubbles are evaluated from attenuation of ultrasound pulse propagating through the experimental cell filled with lipid bubble solution. It is found that the attenuation spectrum has two dominant peaks in the frequency range of 1.0 through 14.0 MHz due to the acoustic energy absorbed by lipid bubble with resonant oscillations. - T0501-2-5 Molecular Dynamics Analysis of Temperature Change in Nanodroplet Evaporating into Vacuum
YAGUCHI Hisao, TANAKA Ryoichi, YANO Takeru, WATANABE Masao, FUJIKAWA Shigeo
The proceedings of the JSME annual meeting, 2009, 115, 116, The Japan Society of Mechanical Engineers, 2009
Japanese, Molecular dynamics simulations of an argon nanodroplet evaporating into vacuum are carried out to investigate time development of its temperature. Configuration in vaporliquid equilibrium state of the nanodroplet with 3.6 nm in radius at 105 K is adopted as initial configuration of the evaporation. Although the temperature of nanodroplet decreases with time because of the loss of latent heat for evaporation, rapid temperature rise has been observed at about 8.0 ns. Radial distribution function of molecules inside the nanodroplet suggests that phase change from liquid to solid has been occurred. Recovery from the supercooling consequent to release of latent heat for solidification is thought to be cause of this rapid temperature rise. - T0501-2-4 Evaluation of Condensation Coefficient of Water in Near-equilibrium State by Shock Tube and Molecular Gas Dynamics
OGASAWARA Toshiki, YAMANO Daigo, WATANABE Masao, FUJIKAWA Shigeo
The proceedings of the JSME annual meeting, 2009, 113, 114, The Japan Society of Mechanical Engineers, 2009
Japanese, The condensation coefficient of water, ie., the ratio of condensation mass flux of vapor molecules to incoming mass flux at the interface, is evaluated by combining the experiment conducted by a shock tube and the numerical simulation of Gaussian-BGK Boltzmann equation applicable to polyatomic gases. Film condensation occurs on the endwall of a vaporfilled shock-tube, when a shock wave is reflected at the endwall and the vapor becomes supersaturated there. The formed liquid film grows with the lapse of time. The time evolution in thickness of the liquid film is measured by an optical interferometer, and thereby the growth rate of the film is obtained. The rate is incorporated into the kinetic boundary condition at the interface for the Gaussian-BGK Boltzmann equation, and the unique numerical solution of the vaporliquid system is obtained. Values of condensation coefficient in near equilibrium state are found to be close to that evaluated by molecular dynamics simulations at the equilibrium state. - Impact of steam-water mixed spray on silicon and metal surfaces
T. Mashiko, A. Hayashida, Y. Yamada, T. Sanada, M. Watanabe
ECS Transactions, 25, 5, 233, 240, 2009, [Peer-reviewed]
English, International conference proceedings - Post Ion-Implant Photoresist Stripping Using Steam and Water: Pre-treatment in a steam atmosphere and steam-water mixed spray
Toshiyuki Sanada, Masao Watanabe, Atsushi Hayashida, Yoichi Isago
ULTRA CLEAN PROCESSING OF SEMICONDUCTOR SURFACES IX, 145-146, 273, +, 2009, [Peer-reviewed]
English, International conference proceedings - Cleaning Technique Using High-Speed Steam-Water Mixed Spray
Masao Watanabe, Toshiyuki Sanada, Atsushi Hayashida, Yoichi Isago
ULTRA CLEAN PROCESSING OF SEMICONDUCTOR SURFACES IX, 145-146, 43, +, 2009, [Peer-reviewed]
English, International conference proceedings - Post ion-implant photoresist stripping using steam and water: Pre-treatment in a steam atmosphere and steam-water mixed spray
Toshiyuki Sanada, Masao Watanabe, Atsushi Hayashida, Yoichi Isago
Solid State Phenomena, 145-146, 273, 276, Trans Tech Publications Ltd, 2009, [Peer-reviewed]
English, International conference proceedings - Image-based CFD on the Hepatic Portion of the Inferior Vena Cava on Budd-Chiari Syndrome.
MATSUBARA MIZUHO, WATANABE MASAO
日本臨床バイオメカニクス学会誌, 29, 99, 106, 01 Nov. 2008
Japanese - Numerial Analysis on High-Speed Droplet Impact on a Solid Surface : Study on Cavitation Inception(Fluids Engineering)
WATANABE Masao, SANADA Toshiyuki, YAMASE Masao
Transactions of the Japan Society of Mechanical Engineers. B, 74, 744, 1717, 1724, 一般社団法人日本機械学会, 25 Aug. 2008
Japanese, Our experimental results [T. Sanada, et. al., ASME-FEDSM 2007-37129] showed that spraying relatively low pressure stream (0.1MPa-0.2MPa), mixed with super-purified water in the nozzle, on a solid surface, caused harsh erosion. We turned our attention to the occurrence of a strong focused rarefaction wave in the middle of the droplet, possibly cavitation. Experimental results that the degrees of the erosion are heavily dependent on temperature also may support the existence of cavitation. We numerically studied the dynamics of high speed liquid droplet impacts on a solid surface by solving the Euler equation of gas-liquid two phase compressible flow. We discuss the possibility of cavitation as the primary cause of the experimentally observed harsh erosion on the solid surface. - Numerial Analysis on High-Speed Droplet Impact on a Solid Surface (Study on Cavitation Inception)
WATANABE MASAO, SANADA TOSHIYUKI, YAMASE MASAO
日本機械学会論文集 B編, 74, 744, 1717, 1724, The Japan Society of Mechanical Engineers, 25 Aug. 2008
Japanese, Our experimental results [T. Sanada, et. al., ASME-FEDSM 2007-37129] showed that spraying relatively low pressure stream (0.1MPa-0.2MPa), mixed with super-purified water in the nozzle, on a solid surface, caused harsh erosion. We turned our attention to the occurrence of a strong focused rarefaction wave in the middle of the droplet, possibly cavitation. Experimental results that the degrees of the erosion are heavily dependent on temperature also may support the existence of cavitation. We numerically studied the dynamics of high speed liquid droplet impacts on a solid surface by solving the Euler equation of gas-liquid two phase compressible flow. We discuss the possibility of cavitation as the primary cause of the experimentally observed harsh erosion on the solid surface. - Motion and drag of a single bubble in super-purified water
Toshiyuki Sanada, Keiji Sugihara, Minori Shirota, Masao Watanabe
Fluid Dynamics Research, 40, 7-8, 534, 545, Jul. 2008
English, Scientific journal - 単一気泡の形状と定常抗力
SATO AYAKA, SHIROTA MINORI, SANADA TOSHIYUKI, WATANABE MASAO
混相流研究の進展, 3, 2008, 35, 41, THE JAPANESE SOCIETY FOR MULTIPHASE FLOW, 15 Jun. 2008
Japanese, Relations between drag coefficients CD and bubble shapes are investigated by comparing our experimental results with both analytical [Moore, J. Fluid Mech., 23, 749-766 (1965)] and numerical results [Blanco & Magnaudet, Phys. Fluids, 7(6), 1265-1274(1995)] on ellipsoidal bubbles rising in a quiescent clean liquid. We clarify that the analytically obtained CD overestimates the experimental results especially in the case of either high aspect ratio or low Reynolds number, and that numerically obtained results for ellipsoidal bubbles well predict our experimental results. We also show that the effect of the deviation in the shape from the ellipsoid, i.e., fore-aft asymmetry, on CD is negligible; CD for fore-aft asymmetry bubbles is in good agreement with the numerically obtained CD for ellipsoidal bubbles. - Formation of a submillimeter bubble from an orifice using pulsed acoustic pressure waves in gas phase
Minori Shirota, Toshiyuki Sanada, Ayaka Sato, Masao Watanabe
PHYSICS OF FLUIDS, 20, 4, 043301, Apr. 2008, [Peer-reviewed]
English, Scientific journal - Development of Cleaning Technique by Using Spray Mixed with Steam and Water
SANADA TOSHIYUKI, SAITO TAKAYUKI, HAYASHIDA ATSUSHI, SAITO TERUO, YAMASE MASAO, WATANABE MASAO
噴流工学, 24, 3, 4-10, 18 Jan. 2008
Japanese - 703 Evaluation of Red Blood Cell Dynamics with High Speed Digital Video Capillaroscopy
NAKAMURA Yuuki, WATANABE Masao, IRIBE Masaki, MATSUBARA Mizuho
The proceedings of the JSME annual meeting, 2008, 21, 22, The Japan Society of Mechanical Engineers, 2008
Japanese, Nailfold video capillaroscopy (NVC) can observe the micro vascular structure non-invasively. We developed NVC by using high speed digital video camera to evaluate both micro vascular structure and red blood cell movement quantitatively The objects of this study are to evaluate the radius distribution of micro vascular by level-set method and also the red blood cell velocity by tracing plasma gap between blood cells. - 337 Advection and Diffusion Transport Phenomena in Engineered Cartilage
NOBAYASHI Makoto, KITAJIMA Yousuke, WATANABE Shouhei, SAWAE Yoshinori, WATANABE Masao
The proceedings of the JSME annual meeting, 2008, 73, 74, The Japan Society of Mechanical Engineers, 2008
Japanese, Engineered cartilages are expected to be used for the treatment of cartilage defects. Cartilage tissue is avascular; hence transport phenomena are controlled by diffusion and also advection by so called "pumping mechanism" of tissue. The objective of present paper is to evaluate the contribution of both diffusion and advection in engineered tissue for the control of transport phenomena. - Motion and drag of single bubbles in super-purified water
Toshiyuki Sanada, Keiji Sugihara, Minori Shirota, Masao Watanabe
FLUID DYNAMICS RESEARCH, 40, 534, 545, Jan. 2008, [Peer-reviewed] - Impact of High-speed steam-droplet spray on solid surface
Toshiyuki Sanada, Masao Watanabe, Minori Shirota, Masao Yamase, Takayuki Saito
FLUID DYNAMICS RESEARCH, 40, 627, 636, Jan. 2008, [Peer-reviewed] - Bubble wake visualization by using photochromic dye
Toshiyuki Sanada, Minori Shirota, Masao Watanabe
CHEMICAL ENGINEERING SCIENCE, 62, 24, 7264, 7273, Dec. 2007, [Peer-reviewed]
English, Scientific journal - Behavior of single rising bubbles in superpurified water
Keiji Sugihara, Toshiyuki Sanada, Minori Shirota, Masao Watanabe
KAGAKU KOGAKU RONBUNSHU, 33, 5, 402, 408, Sep. 2007
Japanese, Scientific journal - フォトクロミック染料による気泡後部定在渦の可視化
SHIROTA MINORI, ONO TOMOKI, SUGIHARA KEIJI, SANADA TOSHIYUKI, WATANABE MASAO
混相流研究の進展, 2, 125, 132, 01 Apr. 2007
Japanese - Formation of Single Bubble of Sub-millimeter Size Using Pulsed Pressure Fluctuation of Gas
SHIROTA MINORI, SANADA TOSHIYUKI, ARATA YASUHIRO, WATANABE MASAO, KAMEDA MASAHARU
日本機械学会論文集 B編, 73, 726, 467, 473, The Japan Society of Mechanical Engineers, 25 Feb. 2007
Japanese, The mechanism of a bubble production method using controlled gas pressure fluctuation, originally developed by Kariyasaki and Osaka [Trans. JSME, Series B, Vol.68, No.674, (2002)1, is further investigated using high-speed photography. We found out more appropriate pressure fluctuation than that of Kariyasaki and Osaka in producing single bubble. The radius of bubbles can be varied from about 0.3 to 0.8 mm with extremely small standard deviation of less than 1μm. Shrinking motion of a capillary bridge connecting a bubble and a nozzle was observed in detail. Force balance on a growing bubble which is based on a spherical bubble formation model is also estimated. As a result, we reveal that when gas pressure is decreased the capillary bridge is sucked down into a nozzle and upward added mass force is applied on a bubble, both of which cause the detachment of a bubble from a nozzle. - No-slip Boundary Condition on Complex Geometry in Lattice Boltzmann Method (1st Report, Construction of Space-Time Bounce-Back Method)
WATANABE MASAO, SANADA TOSHIYUKI, SHIROTA MINORI, MATSUKUMA YOSUKE
日本機械学会論文集 B編, 73, 726, 459, 466, The Japan Society of Mechanical Engineers, 25 Feb. 2007
Japanese, A new treatment of no slip boundary condition on complex geometry in a lattice Boltzmann method is proposed. We developed Space-Time Bounce-Back (STBB) method, which evaluate distribution functions in the vicinity of the solid boundary whose geometry described in the scale less than the lattice size. The STBB method is based on not only the spatial distribution but also the temporal distribution of distribution functions, in order to satisfy both the complete reflection on the solid boundary and the second order accuracy in the spatial discretization. Two-dimensional channel flow is calculated by using the proposed method, and both the accuracy and the stability are examined by comparing with the analytical solution. - High Speed Digital Video Capillaroscopy: Nailfold Capillary Shape Analysis and Red Blood Cell Velocity Measurement
WATANABE Masao, MATSUBARA Mizuho, SANADA Toshiyuki, KURODA Hiroaki, IRIBE Masaki, FURUE Masutaka
JBSE, 2, 2, 81, 92, The Japan Society of Mechanical Engineers, 2007
English, Nailfold capillaroscopy has been shown to reflect microvascular disturbances mainly in connective tissue diseases, and the development of video capillaroscopy made it possible to determine capillary red blood cell velocity by measuring the displacement of plasma gaps between red cells. We improved both temporal and spatial resolutions of video capillaroscopy by developing the high speed digital video capillaroscopy, integrating high speed digital video camera, deep-focus zoom lens, appropriate light source and light collecting adaptor. The first objective of this study is to present the novel method for quantitative capillary shape analysis by using the level-set method. The capillary radius distribution along the capillary center line is obtained and described by the level-set function. Based on this mathematical description of capillary shape, more rigorous definition of the capillary red blood cell velocity than the conventional method is discussed. The second objective of this study is to propose the innovative measurement method of red blood cell velocity in nailfold capillary, and then the possibility of tracking the individual red blood cell movement, not only in the axial direction but also lateral direction, in human nailfold capillary is discussed - Fluid Dynamic Study on Budd-Chiari Syndrome: Sensitivity Study of Vessel Reconstruction on Image-Based Simulation
MATSUBARA Mizuho, WATANABE Masao, WATANABE Satoshi, KONISHI Kozo, YAMAGUCHI Shohei, HASHIZUME Makoto
JBSE, 2, 2, 69, 80, The Japan Society of Mechanical Engineers, 2007
English, Budd-Chiari syndrome (BCS) is a symptomatic complete or partial occlusion of the hepatic vein and/or the inferior vena cava. The cause of BCS is not well known yet, however; abnormal vessel wall shear stress caused by blood flow is thought to increase the likelihood of developing BCS. We investigate the blood flow field in the vicinity of the junction of the inferior vena cava and hepatic veins by using numerical simulation based on medical imaging. However, there exist inaccuracies in computational vessel models. The sensitivities of flow characteristics to vessel shape have not been fully investigated. In this study, the characteristics of the blood flow in the vicinity of the junction of the hepatic vein and the inferior vena cava are discussed based on the numerical results obtained by several reconstructed vessel models which are slightly different in shapes and surface smoothness. It is also demonstrated that relatively small differences in the shapes and surface smoothness of the reconstructed vessel model cause noticeable effects on the flow characteristics in the vicinity of the junction of the inferior vena cava and large hepatic veins. - 1444 High Speed Video Capillaroscopy and Capillary Vessel Blood Flow
IRIBE Masaki, KURODA Hiroaki, WATANABE Masao, MATSUBARA Mizuho, SANADA Toshiyuki
The proceedings of the JSME annual meeting, 2007, 87, 88, The Japan Society of Mechanical Engineers, 2007
Japanese, Nailfold video capillaroscopy (NVC) examines the micro vascular structure noninvasively and aids in the diagnosis of capillary disease, such as Raynaud's phenomenon. We developed high speed digital video capillaroscopy which is composed of high speed digital video camera, deep-focus lens, metal halide light source, and light collecting adaptor. We obtained sequential images of nailfold microcirculation loop with much higher temporal resolution than conventional capillaroscopy. The high speed digital video capillaroscopy enabled us to evaluate quantitatively both micro vascular structure and red blood cell movement. The objects of this study are to measure the radius distribution of micro vascular by Level Set method and also the red blood cell velocity by tracing plasma gap between blood cells. - 1468 Visualization of Single Rising Bubble Wake
TAKEDOMI Yuta, SATO Ayaka, SHIROTA Minori, SANADA Toshiyuki, WATANABE Masao
The proceedings of the JSME annual meeting, 2007, 133, 134, The Japan Society of Mechanical Engineers, 2007
Japanese, The structure of the flow around a rising bubble in silicone oil was visualized by using photochromic dye. We present the first experimental evidence of the existence of the standing eddy, which was predicted numerically by Blanco & Magnaudet[Phys. Fluids, Vol.7, 1265-1274(1995)]. We also experimentally evaluated two kinds of critical aspect ratios over which the standing eddy or three dimensional wake exists. It was found that experimentally obtained critical aspect ratios were smaller than those obtained numerically, however both experimental and numerical results qualitatively agree that critical aspect ratios were bigger in lower Reynolds number. - 1127 Image-based CFD of Blood Flow in the Hepatic Portion of the Inferior Vena Cava on Budd-Chiari Syndrome
MATSUBARA Mizuho, WATABANE Masao, WATANABE Satoshi, KONISHI Kozo, YAMAGUCHI Shohei, HASHIZUME Makoto
The proceedings of the JSME annual meeting, 2007, 93, 94, The Japan Society of Mechanical Engineers, 2007
Japanese, Budd-Chiari syndrome (BCS) is one of the vessel disorders caused by thrombosis which occlude partially or completely hepatic veins (HVs) and the inferior vena cava (IVC). It has been demanded to model the blood flow fields in the IVC and HVs to study the cause of formation of thrombosis. In order to analyze the blood flow fields, we carried out medical vessel segmentation of HVs and IVC using level set method, constructed 3D vessel model, and conducted computational fluid dynamics simulation by using velocity profile of the analytical solution for pulsatile flow in the IVC. - Bubble Wake Visualization by using Photochromic Dye
SANADA Toshiyuki, SHIROTA Minori, ONO Tomoki, WATANABE Masao
Transactions of the Visualization Society of Japan, 27, 7, 47, 52, The Visualization Society of Japan, Jan. 2007, [Peer-reviewed]
Japanese, Wake structure of zigzagging or spiraling motion of free rising bubbles was experimentally investigated. Single bubbles were generated in a silicone oil pool and the wake structure was visualized by using Phtochromic dye. Both bubble motion and wake were observed by using stereo high-speed video cameras. As results, a pair of vortex filaments, which is referred to as double-threaded type wake, was observed in the wake of a bubble rising in axi-asymmetric path. Periodical generation of horse-shoe type vortices were observed when the bubble rose with shape oscillations. - In-line motion of a pair of bubbles in a viscous liquid
M Watanabe, T Sanada
JSME INTERNATIONAL JOURNAL SERIES B-FLUIDS AND THERMAL ENGINEERING, 49, 2, 410, 418, May 2006, [Peer-reviewed]
English, Scientific journal - 2533 Site calibration by with the aid of CFD
FUJINO Masatoshi, SHIROTA Minori, SANADA Toshiyuki, MATSUSHITA Daisuke, WATANABE Masao, MATSUMIYA Hikaru
The proceedings of the JSME annual meeting, 2006, 271, 272, The Japan Society of Mechanical Engineers, 2006
Japanese, In order to measure a wind turbine performance on a complex terrain that fails to satisfy the IEC standard, we should evaluate a flow correction factor which is the ratio of wind speeds between two points. In this study, we have compared the flow correction factors for 16 principal azimuthal directions between actual measurements and CFD results. From March in 2005 to February in 2006, wind speed and wind direction were measured by using two meteorological. And we calculate unsteady wind fields using highly accurate CFD method combined with both large eddy simulation and geographical information system. As a result, in 6 of 16 directions, the flow correction factors obtained from measurements differ from that obtained using CFD by only 〜10%. - 2606 Formation of single bubbles controlled with fluctuating gas pressure
SANADA Toshiyuki, SHIROTA Minori, ARATA Yasuhiro, WATANABE Masao
The proceedings of the JSME annual meeting, 2006, 273, 274, The Japan Society of Mechanical Engineers, 2006
Japanese, A method of a bubble production, originally developed by Kariyasaki and Osaka [Trans. JSME, 68-674B (2002)], is further investigated experimentally. First, the acoustic characteristic of the pipe between audio speaker and nozzle is investigated. Then, a new type of fluctuation consisted of both increase and decrease in gas pressure is used to clarify the effect of the fluctuation. Shrinking motion of a capillary bridge connecting a bubble and a nozzle was observed in detail using high-speed photography. We also estimate the force balance on a bubble center based on a spherical bubble formation model. As results, it is clarified that the pipe between speaker and nozzle could regard as acoustic tube. Moreover, when gas pressure is decreased the capillary bridge is sucked down into a nozzle and upward added mass force is applied on a bubble center, both of which cause the detachment of a bubble from a nozzle. - 4223 Bouncing and Coalescence of a pair of Bubbles in a Quiescent Liquid
SUGIHARA Keiji, ONO Tomoki, SHIROTA Minori, SANADA Toshiyuki, WATANABE Masao
The proceedings of the JSME annual meeting, 2006, 445, 446, The Japan Society of Mechanical Engineers, 2006
Japanese, We experimentally studied both bouncing and coalescence of a pair of bubbles rising side by side in a quiescent liquid. At high Reynolds number, a pair of bubbles approached each other and then collided. After the collision, bubbles either coalesced or bounced. We visualized flow field formed in the vicinity of bubbles by irradiating photochromic dye with UV light sheet, and observed wake of bubbles both before and after the collision. We discuss wake development of bubbles as bubbles collided and the relation between wake structure and bubble motion after the collision. We also investigated the critical Reynolds number and Weber number of coalescence of bubbles. We clarified that the critical Weber number is approximately two regardless of Morton number and that the critical Reynolds number decreases with the increase in Morton number. - 706 Macro-scale transport phenomena in articular cartilage
SUGINO Shouichi, KITAJIMA Yousuke, WATANABE Masao, SAWAE Yoshinori, SANADA Toshiyuki, MURAKAMI Teruo
The proceedings of the JSME annual meeting, 2006, 215, 216, The Japan Society of Mechanical Engineers, 2006
Japanese, Articular cartilage is charactericstic tissue which is mainly composed of avascular extracellular matrix. Solute transport in articular cartilage is to mainly by diffusion across the articular surface. We engineered regenerated cartilage by seeding bovine chondrocyte into agarose gel as scaffold. We evaluate diffusion coefficient by using fluorescent molecular with image process and to examine the effect of molecular weight and electric property of fluorescent labeled dextran on diffusion process in regenerated cartilage tissue. - 527 Image-based Computational Fluid Dynamics Study on Budd-Chiari Syndrome
MATSUBARA Mizuho, WATABANE Masao, WATANABE Satoshi, KONISHI Kozo, YAMAGUCHI Shohei, HASHIZUME Makoto
The proceedings of the JSME annual meeting, 2006, 109, 110, The Japan Society of Mechanical Engineers, 2006
Japanese, Budd-Chiari syndrome (BCS) is one of vessel disorders caused by thrombosis which occlude partially or completely hepatic vein and inferior vena cava. The cause of BCS has not been revealed yet, but it has been indicated that there are some relationships between BCS and blood flow fields in the vicinity of the confluence of hepatic vein with inferior vena cava. In order to analyze the blood flow fields, we carried out medical vessel segmentation of hepatic vein and vena cava using level set method with high accuracy, constructed 3D vessel model, and conducted computational fluid dynamics (image-based CFD). - Interaction and coalescence of bubbles in stagnant liquid
T. Sanada, M. Watanabe, T. Fukano
Multiphase Science and Technology, 18, 2, 155, 174, 2006, [Peer-reviewed]
English, Scientific journal - High-speed videomicroscopic in vivo analysis of human capillary vessel loop
T. Sanada, M. Watanabe, Y. Sawae, M. Furue
PROCEEDINGS OF THE 5TH WORLD CONGRESS OF BIOMECHANICS, 451, +, 2006, [Peer-reviewed]
English, International conference proceedings - Effects of viscosity on coalescence of a bubble upon impact with a free surface
T Sanada, M Watanabe, T Fukano
CHEMICAL ENGINEERING SCIENCE, 60, 19, 5372, 5384, Oct. 2005, [Peer-reviewed]
English, Scientific journal - Noninvasive in vivo Human Capillary Vessel Blood Flow analysis.
WATANABE MASAO, SANADA TOSHIYUKI, SAWAE YOSHINORI, FURUE MASUTAKA
日本臨床バイオメカニクス学会誌, 26, 91, 96, 01 Oct. 2005
Japanese - ヒト皮膚毛細管動静脈ループの高速度観察と血流動態解析
WATANABE MASAO, SANADA TOSHIYUKI, SAWAE YOSHINORI, MASUDA SADAKAZU, FURUE MASUTAKA
西日本皮膚科, 67, 5, 546, 01 Oct. 2005
Japanese - Behavior of a single coherent gas bubble chain and surrounding liquid jet flow structure
T Sanada, M Watanabe, T Fukano, A Kariyasaki
CHEMICAL ENGINEERING SCIENCE, 60, 17, 4886, 4900, Sep. 2005, [Peer-reviewed]
English, Scientific journal - ヒト皮膚毛細管動静脈ループの高速度観察と血流動態解析
FURUE MASUTAKA, MASUDA TEIICHI, WATANABE MASAO, SANADA TOSHIYUKI, SAWAE YOSHINORI
福岡医学雑誌, 96, 6, 277, 277, 福岡医学会, 25 Jun. 2005
Japanese, 人の末梢血管は皮膚表層の表皮下真皮乳頭層の血管を最小血管とする血流網を形成している.乳頭層の細小血管は皮膚表面を拡大すると,そのループの頂点を観察できるわけであるが,指爪郭の爪上皮(あまかわの所)部では,その全容を観察することが可能である.たとえば皮膚筋炎では,毛細管の拡張や出血が認められるが,爪郭の毛細管ではその病態がはっきりと可視化されている.本研究では,皮膚毛細管動静脈ループを流れる血流の血行動態を,毛細血管顕微鏡と高速度ビデオカメラとを組み合わせることにより,非侵襲・非観血で高時空間分解能に観察する手法を開発した. - Numerical site calibration in Takashima
FUJINO Masatoshi, SANADA Toshiyuki, MATSUSHITA Daisuke, UCHIDA Takanori, WATANABE Masao, MATUMIYA Hikaru
Proceedings of Japan Wind Energy Symposium, 27, 265, 268, Japan Wind Energy Association, 2005
Japanese - 210 In vivo flow and shape observation of human microcirculation
SANADA Toshiyuki, WATANABE Masao, SAWAE Yoshinori, FURUE Masutaka
Proceedings of the JSME Bioengineering Conference and Seminar, 2004, 57, 58, The Japan Society of Mechanical Engineers, 2005
Japanese - 232 Visualization of transport phenomena in engineered articular cartilage : Effect of chondrocyte metabolism
WATANABE Masao, SAWAE Yoshinori, SANADA Toshiyuki, HAARI Kenta, MURAKAMl Teruo
Proceedings of the JSME Bioengineering Conference and Seminar, 2004, 279, 280, The Japan Society of Mechanical Engineers, 2005
Japanese - Motion of a pair of bubbles rising in line
Masao Watanabe, Toshiyuki Sanada
Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 71, 702, 389, 396, Japan Society of Mechanical Engineers, 2005
Japanese, Scientific journal - Quantitative Evaluation of Contour Segmentation of Three Dimensional Image Using Level Set Method
WATANABE MASAO, HIMENO RYUTARO
日本機械学会論文集 A編, 70, 697, 1276, 1283, The Japan Society of Mechanical Engineers, 25 Sep. 2004
Japanese, Quantitative evaluation of level set contour segmentation method applied to three dimensional images detecting image edge based on threshold is discussed. The integration of two popular level set methods, i.e., reinitialization method and geodesic active contour method, leads to success in development of robust, with high accuracy, level set based segmentation method. The applications of this method to both synthetic and clinical medical images are shown. Accuracy of the propose method, in the view of both averaged contour location and standard deviation of curvature in the vicinity of contour, calculated using obtained level set function is discussed. - Viscosity Effects on Coalescence of a Pair of Bubbles
Sanada Toshiyuki, Watanabe Masao, Sato Ayaka, Fukano Tohru
Asian Pacific Confederation of Chemical Engineering congress program and abstracts, 2004, 709, 709, The Society of Chemical Engineers, Japan, 2004
English, Effects of liquid viscosity on coalescence of a pair of bubbles were experimentally studied by generating nitrogen gas bubbles in a pool filled with silicon oil. We focused on two types of coalescence/bouncing of bubbles. The first type was those between a rising bubble and a free surface, and the second type was those between of a pair of bubbles rising side by side. The former is considered as the extreme case, which is equivalent to coalescence/bouncing between bubbles with finite and infinite diameters. The later is more practical. That is, bubbles were generated simultaneously from a pair of pin-holes on a pipe horizontally placed. We studied the viscosity effects on coalescence of bubbles by investigating behavior of bubbles with both liquid viscosity and bubble diameter as the parameters. Previous studies reported that We number based on approach velocity could predict whether two bubbles would bounce or coalesce in super purified water. Our experimental results show that the threshold We number in the case of low viscosity liquid indicates same order as the one in the case of super purified water. On the other hand, in the case of large viscosity liquid, the threshold We number differs significantly from the one in the super purified water. - Behavior of a pair of bubbles rising in line
WATANABE Masao, SANADA Toshiyuki
The proceedings of the JSME annual meeting, 2004, 355, 356, The Japan Society of Mechanical Engineers, 2004
Japanese, Behavior and shapes of a pair of bubbles rising in a viscous liquid were numerically analyzed by using DSD/ST (Deforming-Spatial-Domain/Space-Time) Finite Element Method in the cylindrical coordinate system. It has been predicted by the analytical and numerical studies that the trailing bubble approaches the leading bubble and then a pair of bubbles rising in the vertical line keeps the mutual equilibrium distance. However, no experimental results have ever confirmed the existence of the equilibrium distance between a pair of bubbles. In this study, we investigated the effects of bubble deformation on behavior of a pair of bubbles rising in line. We clarified that a pair of deformable bubbles reaches an equilibrium distance and the equilibrium distance is considerably unstable. - Viscosity Effects on Bouncing and Coalescence of a Pair of Bubbles
SANADA Toshiyuki, SATO Ayaka, WATANABE Masao, FUKANO Tohru
The proceedings of the JSME annual meeting, 2004, 351, 352, The Japan Society of Mechanical Engineers, 2004
Japanese, Effects of liquid viscosity on the coalescence of a pair of bubbles were experimentally studied by generating nitrogen gas bubbles in a pool filled with silicon oil. We focused on two types of coalescence/bouncing of bubbles, i.e., those between a rising bubble and a free surface, and between a pair of bubbles rising side by side. The former is considered as the extreme case, which is equivalent to coalescence/bouncing between bubbles with finite and infinite diameters. The later is more practical. That is, bubbles were generated simultaneously from a pair of pin-holes on a pipe horizontally placed. We studied the viscosity effects on coalescence of bubbles by investigating the behavior of bubbles with both liquid viscosity and bubble diameter as the parameters. Previous studies reported that We number based on approach velocity could predict whether two bubbles would bounce or coalesce in superpurified water. Our experimental results show that the threshold in the case of low viscosity liquid indicates the same order as the one in the case of superpurified water. On the other hand, in the case of a large viscosity liquid, the threshold differs significantly from the one in the superpurified water. - Dynamic simulation of the acoustic characteristics of bubble clouds (2nd report, on validity of continuum mathematical model)
Masao Watanabe, Andrea Prosperetti
Nippon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 70, 691, 636, 643, Japan Society of Mechanical Engineers, 2004
Japanese, Scientific journal - Bouncing and coalescence of a bubble approaching to free surface
Toshiyuki Sanada, Masao Watanabe, Tomohiro Yuda, Tohru Fukano
Nippon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 70, 692, 863, 870, Japan Society of Mechanical Engineers, 2004
Japanese, Scientific journal - Viscosity effects on coalescence condition of a pair of bubbles
Toshiyuki Sanada, Masao Watanabe, Ayaka Sato, Tohru Fukano
Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 70, 700, 3128, 3135, Japan Society of Mechanical Engineers, 2004
Japanese, Scientific journal - Study on single bubble chains in stagnant water
Toshiyuki Sanada, Tohru Fukano, Masao Watanabe
Proceedings of the ASME/JSME Joint Fluids Engineering Conference, 2, 1489, 1496, American Society of Mechanical Engineers, 2003
English, International conference proceedings - Effects of generation frequency and bubble diameter on the behaviors of single bubble chains
Toshiyuki Sanada, Masao Watanabe, Akira Kariyasaki, Tohru Fukano
Nippon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 69, 678, 307, 314, Japan Society of Mechanical Engineers, 2003
Japanese, Scientific journal - Single bubble chain behavior and liquid flow structures in the vicinity of a nozzle (liquid jet developments by single bubble chains)
Toshiyuki Sanada, Masao Watanabe, Hitomi Noda, Tohru Fukano
Nippon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 69, 687, 2446, 2452, Japan Society of Mechanical Engineers, 2003
Japanese, Scientific journal - Blood flow field simulation and vessel segmentation in level set frame work for MR angiography (vessel wall description and velocity boundary condition)
Masao Watanabe, Ron Kikinis, Carl-Fredrik Westin
Nippon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 69, 687, 2408, 2415, Japan Society of Mechanical Engineers, 2003
Japanese, Scientific journal - Dynamic Simulation of the Acoustic Characteristics of Bubble Clouds (1st Report, Construction of Mathematical Model)
Masao Watanabe, Andrea Prosperetti
Nippon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 69, 688, 2612, 2619, Japan Society of Mechanical Engineers, 2003
Japanese, Scientific journal - Numerical Simulation of Bubble Motion by Using Finite Element Method with Time Dependent Non-Structured Mesh
Masao Watanabe, Rajendra Shrestha, Tohru Fukano
Proceedings of ASME/JSME Fluids Engineering Division Summer Meeting San Francisco, CA, USA. FEDSM99-7101, 99, 7101, 1999, [Lead author] - Numerical Analysis of Bubble Motion Using Finite Element Method with Time Dependent Non-Structured Interface Capturing Mesh
Masao Watanabe, Rajendra Shrestha, Tohru Fukano
Proceedings of 4th International Joint Symposium between Kyushu University and Chungnam National University, 96, 1999, [Lead author] - Experimental Study of the Behavior of Bubbles Rising in Stagnant Water
Masao Watanabe, Rajendra Shrestha, Tohru Fukano
Memoirs of the Graduate School of Engineering, Kyushu University, 59, 4, 243, 261, Kyushu University, 1999, [Lead author]
English - Bubble Cloud Collapse in an Inviscid and Incompressible Liquid
Masao Watanabe, Tohru Fukano
Proceedings of ASME/JSME Fluids Engineering Division Summer Meeting CA, USA. F. EDSM99-6771, 1999, [Lead author] - Numerical analysis of waves (viscous waves) generated on thin liquid film acompanied by gas flow
Takanari Inatomi, Tohru Fukano, Masao Watanabe
Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 65, 638, 3252, 3259, Japan Society of Mechanical Engineers, 1999
Japanese, Scientific journal - Hydrodynamic force between slightly deformable bubbles at low Reynolds number
M Watanabe, T Fukano
JSME INTERNATIONAL JOURNAL SERIES B-FLUIDS AND THERMAL ENGINEERING, 41, 2, 480, 485, May 1998
English, Scientific journal - Complex Motions of Bubbles in Periodically Driven Pressure Field
Masao Watanabe, Tohru Fukano
Proceedings of International Conference of Multiphase Flow '98, Lyon, France, 1998, [Lead author] - A simplified model for linear and nonlinear processes in thermoacoustic prime movers .1. Model and linear theory
M Watanabe, A Prosperetti, H Yuan
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, 102, 6, 3484, 3496, Dec. 1997
English, Scientific journal - Liquid film formation on the inner surface of the horizontal channel
T Fukano, H Nakagawa, Y Mori, M Watanabe
NUCLEAR ENGINEERING AND DESIGN, 175, 1-2, 3, 13, Nov. 1997, [Peer-reviewed]
English, Scientific journal - SHOCK-WAVES IN DILUTE BUBBLY LIQUIDS
M WATANABE, A PROSPERETTI
JOURNAL OF FLUID MECHANICS, 274, 349, 381, Sep. 1994
English, Scientific journal - The Effect of Gas Diffusion on the Nuclei Population Downstream of a Cavitation Zone
Masao Watanabe, Andrea Prosperetti
Proceedings of the Symposium on Cavitation and Gas-Liquid Flow in Fluid Machinery and Devices, FED-Vol. 190, 211, 1994, [Lead author] - Mass Diffusion Effects on Cavitation Nuclei
Masao Watanabe, Andrea Prosperetti
Proceedings of 2nd International Symposium and Cavitation, Tokyo Japan, 321, 1994, [Lead author] - Numerical simulation on a bubble motion with full N-S equations.
Yoichiro MATSUMOTO, Masao WATANABE
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B, 55, 519, 3282, 3287, Japan Society of Mechanical Engineers, 1989
Scientific journal - Numerical simulation on a bubble motion with full N-S equations.
Yoichiro MATSUMOTO, Masao WATANABE
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B, 55, 519, 3282, 3287, Japan Society of Mechanical Engineers, 1989
Scientific journal - Nonlinear Oscillation of Gas Bubble with Internal Phenomena
Yoichiro Matsumoto, Masao Watanabe
JSME International Journal, Series II, 32, 2, 157, 1988 - Nonlinear Oscillation of Gas Bubble Considering the Internal Phenomena
Yoichiro MATSUMOTO, Masao WATANABE
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B, 54, 501, 1051, 1057, The Japan Society of Mechanical Engineers, 1988
Japanese, The pressure response of a small air bubble in water is calculated numerically in an oscillatory pressure field. The following phenomena are taken into account in the calculation ; mist formation inside the bubble due to homogeneous condensation, diffusion between vapor and noncondensable gas inside the bubble and so on. The internal condition adapts itself easily to the oscillatory pressure field by the internal phenomena, which includes mist formation, evaporation and deposition onto the bubbler wall, so that the bubble tends to oscillate synchronously. The frequency response curves for bubbles are calculated. The curve is shifted towards low frequency, and the maximum bubble radius becomes large. When the pressure amplitude is increased, the periodic bubble oscillation bifurcates to non-periodic oscillation, which is a deterministic chaos. - Nonlinear oscillation of gas bubble with internal phenomena.
MATSUMOTO Yoichiro, WATANABE Masao
Transactions of the Japan Society of Mechanical Engineers Series C, 54, 501, 1051, 1057, The Japan Society of Mechanical Engineers, 1988
Japanese, The pressure response of a small air bubble in water is calculated numerically in an oscillatory pressure field. The following phenomena are taken into account in the calculation ; mist formation inside the bubble due to homogeneous condensation, diffusion between vapor and noncondensable gas inside the bubble and so on. The internal condition adapts itself easily to the oscillatory pressure field by the internal phenomena, which includes mist formation, evaporation and deposition onto the bubbler wall, so that the bubble tends to oscillate synchronously. The frequency response curves for bubbles are calculated. The curve is shifted towards low frequency, and the maximum bubble radius becomes large. When the pressure amplitude is increased, the periodic bubble oscillation bifurcates to non-periodic oscillation, which is a deterministic chaos.
Other Activities and Achievements
- エタノール液滴のスプラッシュ発生に及ぼす蒸気の凝縮効果
澤井 冴, 渡部 正夫, 小林 一道, 藤井 宏之, 真田 俊之, 流体工学部門講演会講演論文集, 2018, OS2-17, May 2019, [Peer-reviewed]
Japanese, Summary national conference - 単一液滴衝突時に取り込まれる空気膜の観察
Riichiro Endo, Masao Watanabe, Kazumichi Kobayashi, Hiroyuki Fujii, 流体工学部門講演会講演論文集, 2018, OS2-5, May 2019, [Peer-reviewed]
Japanese, Summary national conference - Numerical study of light scattering in the human neck for diagnosis of thyroid cancers by optical tomography
Fujii Hiroyuki, Yamada Yukio, Hoshi Yoko, Kobayashi Kazumichi, Watanabe Masao, Extended abstract of the 12th CME International Conference, OS12, 2, 2018
English, Summary international conference - 分子動力学法を用いた高温壁へ衝突するナノ液滴の浮遊メカニズム解析
田部 広風海, 小林 一道, 矢口 久雄, 藤井 宏之, 渡部 正夫, マイクロ・ナノ工学シンポジウム, 2018.9, 30pm4PN16, 2018, [Peer-reviewed]
Japanese, Summary national conference - 高温壁へ衝突する液滴の浮遊メカニズムに関する分子動力学解析
田部 広風海, 小林 一道, 矢口 久雄, 藤井 宏之, 渡部 正夫, 流体工学部門講演会講演論文集, 2018, OS2-1, 2018, [Peer-reviewed]
Japanese, Summary national conference - 粘弾性乳液滴と固体表面の高速衝突の観察
伊藤 一樹, 芦田 拓, 渡部 正夫, 小林 一道, 藤井 宏之, 吉岡 孝一郎, 大井 航, 髙野 真, 流体工学部門講演会講演論文集, 2018, OS2-23, 2018, [Peer-reviewed]
Japanese, Summary national conference - 低圧環境下における高速液滴衝突直後に発生するsplashの観察
芦田 拓, 渡部 正夫, 小林 一道, 藤井 宏之, 真田 俊之, 流体工学部門講演会講演論文集, 2018, OS2-9, 2018, [Peer-reviewed]
Japanese, Summary national conference - Numerical Calculation Of Time-resolved Light Reflectance From Biological Tissue Using The Radiative Transfer Equation
Hiroyuki Fujii, Yukio Yamada, Yoko Hoshi, Kazumichi Kobayashi, Masao Watanabe, Extended abstract of The International Conference on Mathematics in (bio)Chemical Kinetics and Engineering (MaCKiE) 2017, 2017
English, Summary international conference - 拡散光による甲状腺腫瘍診断のためのヒト頸部内における光伝播の数値解析
藤井 宏之, 山田 幸生, 星 詳子, 小林 一道, 渡部 正夫, 第３３回近赤外フォーラム 講演論文集, I, 07, 2017
Japanese, Summary national conference - Laboratory of Fluid Dynamics, Division of Mechanical and Space Engineering, Faculty of Engineering, Hokkaido University
渡部 正夫, 小林 一道, 藤井 宏之, 混相流 = Japanese journal of multiphase flow, 30, 4, 408, 411, Dec. 2016
日本混相流学会, Japanese - 蒸気と気体で満たされた球形気泡の収縮・膨張運動に関する分子気体力学解析
永山 貴大, 今 美沙紀, 小林 一道, 渡部 正夫, 藤井 宏之, 高比良 裕之, 流体工学部門講演会講演論文集, 2016, 0727, 2016, [Peer-reviewed]
Japanese, Summary national conference - Best Presentation Award in JSMF Multiphase Flow Symposium 2015
渡部 正夫, 混相流 = Japanese journal of multiphase flow, 29, 4, 386, 389, Dec. 2015
日本混相流学会, Japanese - 流体物理洗浄（3）ジェット洗浄、ブラシ洗浄、その他
真田 俊之, 渡部正夫, ケミカルタイムズ, 238, (num), 22, 27, 01 Oct. 2015 - 流体物理洗浄(3)ジェット洗浄,ブラシ洗浄,その他
SANADA TOSHIYUKI, WATANABE MASAO, Chem Times, 2015, 4, 16, 21, 01 Oct. 2015
Japanese - J0540204 Numerical simulation of gas shear flow between liquid slab and solid wall by using Enskog-Vlasov equation
KON Misaki, KOBAYASHI Kazumichi, WATANABE Masao, Mechanical Engineering Congress, Japan, 2015, "J0540204, 1"-"J0540204-3", 13 Sep. 2015
The aim of this study is to investigate the relation between the slip velocity at the gas-liquid interface and the rarefaction. We carried out the numerical simulation of the steady shear flow between the liquid slab and the solid wall with changing Knudsen number based on mean field kinetic theory. The simulation results showed that the slip velocity at the gas-liquid interface increases with the increase of Knudsen number. On the other hand, the slip velocity at the gas-solid interface is smaller than that at the gas-liquid interface in all cases of Knudsen number., The Japan Society of Mechanical Engineers, Japanese - J0540301 Numerical Computation of a Mathematical Model Applying Boundary Conditions Derived from Molecular Gas Dynamics at Gas-Liquid Interface for Describing Bubble Behaviors Accompanied by Phase Changes
MORIKAWA Shotaro, JINBO Yoshinori, TATEKURA Yuki, KOBAYASHI Kazumichi, WATANABE Masao, Mechanical Engineering Congress, Japan, 2015, "J0540301, 1"-"J0540301-5", 13 Sep. 2015
The collapse and rebound of a single spherical bubble with phase changes at the vapor-iquid interface are fundamental physical phenomena in the fields of industry and medicine. In this study, we propose a mathematical model of describing the dynamics of a spherical vapor bubble with phase changes (evaporation and condensation) at the vapor-liquid interface. To deal with evaporation and condensation phenomena at the interface precisely, we utilize the boundary condition of the interface derived from the molecular gas dynamics analysis. The calculation results of the mathematical model show that the maximum pressure inside a bubble due to the bubble collapse with phase changes becomes higher than that of the bubble collapse without phase changes., The Japan Society of Mechanical Engineers, Japanese - 流体物理洗浄(1)基本概念と微粒子の付着力
SANADA TOSHIYUKI, WATANABE MASAO, Chem Times, 2015, 2, 17, 23, 01 Apr. 2015
Japanese - Numerical analysis of photon migration in three-dimensional turbid media using the delta-Eddington approximation
Hiroyuki Fujii, Shinpei Okawa, Ken Nadamoto, Eiji Okada, Yukio Yamada, Yoko Hoshi, Masao Watanabe, Extended abstract of the 9th CME International Conference, OS6, 4, 2015
English, Summary international conference - 反射衝撃波によって誘起される非凝縮性気体を伴う蒸気の凝縮現象に関する分子気体力学に基づく数値計算
永山 貴大, 藤井 宏之, 小林 一道, 渡部 正夫, 日本機械学会年次大会, 2015, J0540205, 2015
Japanese, Summary national conference - シリンジを用いた高速液滴射出装置の開発および液滴衝突の観察
片岡 豊, 堀 優作, 渡部 正夫, 小林 一道, 藤井 宏之, 日本機械学会年次大会, 2015, G0500203, 2015
Japanese, Summary national conference - 異なる境界条件を課した生体モデルにおける光伝播の数値解析
服部 聖仁, 藤井 宏之, 小林 一道, 渡部 正夫, 日本機械学会年次大会, 2015, J2410103, 2015
Japanese, Summary national conference - 固体壁面の濡れ性が液滴衝突により発生する流れの進展挙動に与える影響の観察
山口 陽平, 渡部 正夫, 小林 一道, 藤井 宏之, 真田 俊之, 流体工学部門講演会講演論文集, 2015, 317, 2015, [Peer-reviewed]
Japanese, Summary national conference - 低圧環境下での高速液滴衝突によるSplash発生の観察
東 稜, 渡部 正夫, 小林 一道, 藤井 宏之, 流体工学部門講演会講演論文集, 2015, 318, 2015, [Peer-reviewed]
Japanese, Summary national conference - シリンジを用いた高速微細液滴射出装置の開発
堀 優作, 片岡 豊, 渡部 正夫, 小林 一道, 藤井 宏之, 流体工学部門講演会講演論文集, 2015, 319, 2015, [Peer-reviewed]
Japanese, Summary national conference - エタノール液滴と固体壁の衝突現象に周囲気体種が及ぼす影響
磯野 俊悠, 渡部 正夫, 小林 一道, 藤井 宏之, 日本機械学会年次大会, 2015, G0500202, 2015
Japanese, Summary national conference - 生体光イメージングのためのヒト頸部内光伝播モデルの構築
藤井 宏之, 大川 晋平, 灘本 健, 岡田 英史, 山田 幸生, 星 詳子, 渡部 正夫, バイオエンジニアリング講演会講演論文集, 2015.27, 1G21, Jan. 2015
Japanese, Summary national conference - Student Presentation Award in JSMF Multiphase Flow Symposium 2013
渡部 正夫, 混相流, 27, 4, 472, 476, Dec. 2013
日本混相流学会, Japanese - J053025 Numerical Simulation for Kinetic Boundary Condition at a Vapor-Liquid Interface Based Enskog-Vlasov Equation
KOBAYASHI Kazumichi, KON Misaki, OHASHI Kotaro, WATANABE Masao, Mechanical Engineering Congress, Japan, 2013, "J053025, 1"-"J053025-4", 08 Sep. 2013
The aim of the present study is to investigate the kinetic boundary condition (KBC) at a vapor-liquid interface in net evaporation/condensation states by using the Enskog-Vlasov equation. Our target system is a steady evaporation and condensation state between two liquid slabs with different temperatures. The results show that we can realize the simulation of steady evaporation and condensation phenomena between the two-liquid slabs with different temperature. Also, the normal and tangential temperatures including the kinetic boundary condition is not only the function of molecular energy flux but also the function of molecular collision mass flux in net condensation interface., The Japan Society of Mechanical Engineers, Japanese - J053024 Molecular dynamics analysis on evaporation of argon liquid in argon-neon system
HORI Kazumasa, YAHAGI Takato, TAKEUCHI Shinnosuke, YAGUCHI Hisao, KOBAYASHI Kazumichi, WATANABE Masao, Mechanical Engineering Congress, Japan, 2013, "J053024, 1"-"J053024-5", 08 Sep. 2013
The aim of the present study is to establish the kinetic boundary condition of a vapor-liquid interface for argon-neon two-component systems by using the molecular dynamics simulation. Two kinds of simulations were conducted: vapor-liquid equilibrium and evaporation simulations at the liquid temperature 85 K. In this paper, we investigated the influence of mole rate of neon for the evaporation flux of argon and calculated the value of the evaporation coefficient. The results show that as the mole rate of neon increases, the evaporation coefficient of argon becomes smaller. The main factor for the decrease of evaporation coefficient is the increase of the outgoing molecular mass flux at the equilibrium states due to the increase of mole rate of neon. Further, the velocity distribution function of argon composed of the evaporating molecules deviates from the half - Maxwellian with the liquid temperature., The Japan Society of Mechanical Engineers, Japanese - Numerical analysis of nonequilibrium evaporation/condensation phenomena by Enskog-Vlasov equation
Kon Misaki, Kobayashi Kazumichi, Watanabe Masao, Meeting abstracts of the Physical Society of Japan, 68, 2, 248, 248, 26 Aug. 2013
The Physical Society of Japan (JPS), Japanese - 304 Numerical analysis of high-speed droplet spray flow in cleaning nozzle
Tamura Toshiyuki, Kawahara Junya, Kobayashi Kazumichi, Watanabe Masao, 北海道支部講演会講演概要集, 2012, 51, 83, 84, 20 Oct. 2012
The Japan Society of Mechanical Engineers, Japanese - (9)Unified Theory Based on Parameter Scaling for Derivation of Nonlinear Wave Equations in Bubbly Liquids
金川 哲也, 矢野 猛, 渡部 正夫, 藤川 重雄, Journal of the Japan Society of Mechanical Engineers, 115, 1122, 265, 266, 05 May 2012
The Japan Society of Mechanical Engineers, Japanese - J054032 Molecular Gas Dynamics on Resonant Gas Oscillations Accompanied with Phase Changes at Vapor-Liquid Interface
INABA Masashi, YANO Takeru, WATANABE Masao, KOBAYASHI Kazumichi, FUJIKAWA Shigeo, Mechanical Engineering Congress, Japan, 2011, "J054032, 1"-"J054032-2", 11 Sep. 2011
The resonant gas oscillation excited in a one-dimensional space between an oscillating plate and a planer surface of a thin liquid layer on a quiescent rigid-wall is considered. Vapor flows with evaporation or condensation at the vapor-liquid interface are theoretically studied on the basis of a polyatomic version of Gaussian-BGK Boltzmann equation with a kinetic boundary condition including an evaporation coefficient., The Japan Society of Mechanical Engineers, Japanese - J054031 Measurements of the Evaporation Coefficient of Water Using Sound Resonance Method
NAKAMURA Shigeto, YANO Takeru, KOBAYASHI Kazumichi, WATANABE Masao, FUJIKAWA Shigeo, Mechanical Engineering Congress, Japan, 2011, "J054031, 1"-"J054031-4", 11 Sep. 2011
We propose a new method for measurement of the evaporation coefficient using sound resonance experiment based on a theory of molecular gas dynamics. The evaporation coefficient is one of the parameters contained in the kinetic boundary condition. The evaporation coefficient of water is determined from the pressure amplitude of resonant sound wave in a cylindrical space bounded by a sound source and a vapor-liquid interface. By comparing the pressure amplitude with a linear theory based on molecular gas dynamics, we prove that the evaporation coefficient of water is about 1.0 around 300K., The Japan Society of Mechanical Engineers, Japanese - J054033 Numerical Simulations for Couette flows in Dense Gas Based on Enskog Equation
KOBAYASHI Kazumichi, OHASHI Kotarou, INABA Masashi, WATANABE Masao, FUJIKAWA Shigeo, Mechanical Engineering Congress, Japan, 2011, "J054033, 1"-"J054033-5", 11 Sep. 2011
Numerical simulations for Couette flows in a dense gas are conducted based on the Enskog equation. In order to solve the Enskog equation, we use the particle scheme method, which is an extension of the well known DSMC method that is used to solve the Boltzmann equation. The results agree well with the solution of the Boltzmann equation, as the ratio of molecular diameter to the mean free path of the molecules, a/ A, becomes smaller. A thin layer is formed near a solid wall surface as the ratio al A becomes larger. We also find that the slip velocity on the solid surface depends on the ratio al A., The Japan Society of Mechanical Engineers, Japanese - Report on the 14th Organized Multiphase Flow Forum (OMF2010-Jozankei)
MURAI Yuichi, NARABAYASHI Tadashi, WATANABE Masao, Japanese journal of multiphase flow, 25, 1, 60, 63, 15 Mar. 2011
日本混相流学会, Japanese - 403 Human Nailfold Capillary Shape Analysis and Red Blood Cell Velocity Measurement
佐野 宏典, 矢口 久雄, 小林 一道, 渡部 正夫, 藤川 重雄, 北海道支部講演会講演概要集, 2010, 49, 83, 84, 07 Nov. 2010
The Japan Society of Mechanical Engineers, Japanese - 0407 Nonlinear Waves in Liquid Containing Microbubbles Encapsulated by Visco-Elastic Shell
KANAGAWA Tetsuya, WATANABE Masao, YANO Takeru, FUJIKAWA Shigeo, Fluids engineering conference ..., 2010, 133, 134, 29 Oct. 2010
Nonlinear propagation of pressure waves in an initially quiescent liquid containing non-uniformly distributed spherical microbubbles is theoretically studied on the basis of the method of multiple scales. We focus on almost unidirectional waves propagating mainly in one direction with a weak diffraction or weak focusing to the transverse direction (like a ultrasound beam). Based on a methodology recently proposed by the authors, the KZK type equation, in which the dispersion and the non-uniformity of number density of bubbles are considered, is derived from the basic equations of bubbly flows., The Japan Society of Mechanical Engineers, Japanese - 301 Evaluation of Evaporation Coefficient at Spherical Vapor-Liquid Interface of Nanodroplet
矢口 久雄, 矢野 猛, 渡部 正夫, 藤川 重雄, The Computational Mechanics Conference, 2010, 23, 292, 294, 23 Sep. 2010
The Japan Society of Mechanical Engineers, Japanese - 303 マイクロ液滴噴霧洗浄技術開発のための高速ノズル流動解析(OS3. ナノ・マイクロ熱流動現象(1),オーガナイズドセッション講演)
高橋 広樹, 渡部 正夫, 小林 一道, 藤川 重雄, 計算力学講演会講演論文集, 2010, 23, 297, 298, 23 Sep. 2010
一般社団法人日本機械学会, Japanese - 302 壁面に衝突する高速マイクロ液滴挙動に及ぼす液滴温度の効果(OS3. ナノ・マイクロ熱流動現象(1),オーガナイズドセッション講演)
ユ ヨンゼ, 渡部 正夫, 小林 一道, 藤川 重雄, 計算力学講演会講演論文集, 2010, 23, 295, 296, 23 Sep. 2010
一般社団法人日本機械学会, Japanese - Weakly Nonlinear Analysis for Resonant Gas Oscillations with Evaporation and Condensation
Inaba Masashi, Yano Takeru, Watanabe Masao, Kobayashi Kazumichi, Fujikawa Shigeo, 日本流体力学会年会講演論文集, 2010, 102, 102, 2010
The behavior of resonant sound waves in a finite one-dimensional space between an oscillating plate (sound source) and a vapor-liquid interface is analyzed by applying the asymptotic theory for Kn<Evaporation Coefficient at a Spherical Vapor-Liquid Interface
Yaguchi Hisao, Yano Takeru, Watanabe Masao, Fujikawa Shigeo, 日本流体力学会年会講演論文集, 2010, 284, 284, 2010
Kinetics of phase change at spherical interface between an argon nanodroplet and its vapor is studied by molecular dynamics simulation. The evaporation coefficient is evaluated at spherical control surface around the nanodroplet at 85K, however it depends on not only a radius of the nanodroplet but also that of control surface. Thus we define a new specific control surface, where the mass flux of evaporating molecules from the nanodroplet into vacuum is equal to that from the planar liquid film. The specific surface is found to be in a few nanometers distance from the center of the vapor-liquid transition layer. We adopt this surface as a interface for evaluating evaporation coefficient and successfully determine the evaporation coefficients for argon nanodroplets ranging from 1 to 4nm in radius. As a result, the evaporation coefficient decreases with decreasing in the radius of the nanodroplet., 日本流体力学会, JapaneseWeakly Nonlinear Propagation of Sound Beam in Bubbly Liquids
KANAGAWA Tetsuya, WATANABE Masao, YANO Takeru, FUJIKAWA Shigeo, 日本流体力学会年会講演論文集, 2010, 258, 258, 2010
Weakly nonlinear propagation of pressure waves in an initially quiescent liquid containing many small spherical gas bubbles is studied for the case of low frequency and long wavelength. We focus on almost unidirectional waves propagating mainly in one direction with a weak diffraction to the transverse direction (like a ultrasound beam), i.e., weakly two-dimensional waves. On the basis of a methodology recently proposed by ourselves, the KZK equation with a dispersion term is systematically derived from the basic equations of bubbly flows., 日本流体力学会, JapaneseNovel Method for Measurement of Evaporation Coefficient
Nakamura Shigeto, Yano Takeru, Kobayashi Kazumichi, Watanabe Masao, Fujikawa Shigeo, 日本流体力学会年会講演論文集, 2010, 283, 283, 2010
We propose a new method for measurement of the evaporation coefficient using nonlinear sound resonance experiment based on a theory of molecular gas dynamics. The evaporation coefficient is determined from the pressure amplitude of second harmonics generated by the nonlinear effect of resonant sound wave in a cylindrical space bounded by a sound source and a gas-liquid interface. To demonstrate the applicability of this method, we conduct a test experiment. As a result, we confirm the increase of second harmonics amplitude caused by the sound resonance., 日本流体力学会, Japanese206 Development of Low-pressure Submerged Water Jet for Organic Compounds Decomposition
中村 謙介, 渡部 正夫, 藤川 重雄, 北海道支部講演会講演概要集, 2009, 48, 45, 46, 28 Nov. 2009
The Japan Society of Mechanical Engineers, Japanese1605 Visualization of Nailfold Micro-circulation Using High-speed Video Capillaroscopy
WATANABE Masao, NAKAMURA Yuuki, SANO Hironori, YAGUCHI Hisao, Fluids engineering conference ..., 2009, 491, 492, 06 Nov. 2009
Capillaroscopy is a "lens" that is able to observe capillary loops of blood vessels in the human finger skin nail fold, of which blood flow can be easily visualized, and has been long used for clinical diagnosis. We have been developing digital high speed video capillaroscopy by integrating to high-speed high-sensitivity video camera with deep-focus zoom lens. We discuss quantitative evaluation of blood velocity in both arteriol and venule of human nailfold microcirculation, using two different methods, namely, plasma gap tracking method and fixed point observation method with correlation., The Japan Society of Mechanical Engineers, Japanese30aTJ-5 Molecular Dynamics Study of Vapor-liquid Equilibrium Condition of Nanodroplet
Yaguchi Hisao, Yano Takeru, Watanabe Masao, Fujikawa Shigeo, Meeting abstracts of the Physical Society of Japan, 64, 1, 319, 319, 03 Mar. 2009
The Physical Society of Japan (JPS), Japanese318 Noninvasive Observation of Red Blood Cell Dynamics with High Speed Digital Video Capillaroscopy
NAKAMURA Yuuki, IRIBE Masaki, MATSUBARA Mizuho, WATANABE Masao, バイオエンジニアリング講演会講演論文集, 2008, 21, 127, 128, 22 Jan. 2009
The Japan Society of Mechanical Engineers, Japanese508 Transport Phenomena in Scaffold Gel for Engineered Cartilage
NOBAYASHI Makoto, WATANABE Shouhei, NODA Hiroyuki, SAWAE Yoshinori, WATANABE Masao, バイオエンジニアリング講演会講演論文集, 2008, 21, 199, 200, 22 Jan. 2009
The Japan Society of Mechanical Engineers, JapaneseMolecular Gas Dynamics on Resonant Sound Waves Excited in One-Dimensional Space between Oscillating Plate and Vapor-Liquid Interface
INABA Masashi, YANO Takeru, WATANABE Masao, FUJIKAWA Shigeo, 日本流体力学会年会講演論文集, 2009, 124, 124, 2009
The behavior of resonant sound waves in a finite one-dimensional space between an oscillating plate (sound source) and a vapor-liquid interface is analyzed by applying the asymptotic theory for Kn<Evaluation of Evaporation Coefficient at the Vapor-liquid Interface of Argon Nanodroplet by Molecular Dynamics Method
Yaguchi Hisao, Yano Takeru, Watanabe Masao, Fujikawa Shigeo, 日本流体力学会年会講演論文集, 2009, 217, 217, 2009
Mass fluxes and evaporation coefficients at the interface between an argon nanodroplet and its vapor are investigated by nonequilibrium molecular dynamics (MD) simulations. The simulations are carried out at the temperatures of 85, 90, 95, 100, and 105K with droplet radii ranging from about 1nm to 4nm. The evaporation mass fluxes J_are obtained by MD simulations of evaporation into vacuum and are found to be almost independent of droplet radius at the specified control surface R_ . Since the outgoing mass flux J_ in an equilibrium state becomes large as the droplet radius does small, the evaporation coefficient α_e, defined by the ratio of J_ to J_ , decreases with decrease in the droplet radius., 日本流体力学会, Japanese Weakly Nonlinear Propagation of Quasi-Monochromatic Waves in Bubbly Liquids
Kanagawa Tetsuya, Yano Takeru, Watanabe Masao, Fujikawa Shigeo, 日本流体力学会年会講演論文集, 2009, 175, 175, 2009
One-dimensional nonlinear dispersive waves in a liquid containing a number of small spherical gas bubbles are theoretically studied based on a set of two-fluid averaged equations composed of the conservation laws of mass and momentum for gas and liquid phases, and the Keller equation for the bubble dynamics. The liquid compressibility is taken into account, and this leads to the wave attenuation due to bubble oscillations. By using an appropriate scaling of physical parameters and the method of multiple scales, we can derive the nonlinear Schrodinger equation with an attenuation term due to the acoustic radiation and the liquid viscosity. This equation describes a far field of a quasi-monochromatic wave train in the bubbly liquid, which evolves into a slowly modulated wave packet as a result of long range propagation of weakly nonlinear waves with the strong dispersion effect., 日本流体力学会, Japanese門脈血行異常症に関する調査研究 バッドキアリ症候群機序解明のためのイメージベースドCFDによる流体力学的解析
HASHIZUME MAKOTO, WATANABE MASAO, MATSUBARA MIZUHO, KONISHI KOZO, 門脈血行異常症調査研究班 平成20年度研究報告書, 26, 29, 2009
Japanese門脈血行異常症に関する調査研究 バッドキアリ症候群機序解明のためのイメージベースドCFDによる流体力学的解析
HASHIZUME MAKOTO, WATANABE MASAO, MATSUBARA MIZUHO, KONISHI KOZO, 門脈血行異常症調査研究班 平成20年度研究報告書, 87, 89, 2009
Japanese7・2 流体計測(7.流体工学,<特集>機械工学年鑑)
速水 洋, 青木 俊之, 半田 太郎, 田中 和博, 林 秀千人, 佐田富 道雄, 古川 明徳, 塚本 寛, 渡部 正夫, 高曽 徹, 古川 雅人, 金元 敏明, 溝田 武人, 日本機械学會誌, 111, 1077, 662, 667, 05 Aug. 2008
一般社団法人日本機械学会, JapaneseB11 A Numerical Analysis of Liquid Film Formation on a Rotating Disk
MAEDA Daisuke, IWASAKI Tatsuya, WATANABE Masao, SANADA Toshiyuki, 日本機械学会九州支部講演論文集, 2008, 61, 35, 36, 19 Mar. 2008
The Japan Society of Mechanical Engineers, Japanese229 Diffusion transport phenomena in engineered cartilage
WATANABE Shohei, KITAJIMA Yosuke, NOBAYASHI Makoto, WATANABE Masao, MURAKAMI Teruo, SAWAE Yoshinori, バイオエンジニアリング講演会講演論文集, 2007, 20, 295, 296, 24 Jan. 2008
The Japan Society of Mechanical Engineers, Japanese125 Numerical Study of Blood Flow in the Hepatic Portion of the Inferior Vena Cava on Budd-Chiari Syndrome
MATSUBARA Mizuho, WATANABE Masao, WATANABE Satoshi, KONISHI Kozo, HASHIZUME Makoto, バイオエンジニアリング講演会講演論文集, 2007, 20, 257, 258, 24 Jan. 2008
The Japan Society of Mechanical Engineers, Japanese102 Observation of Capillary Vessel Blood Flow by High Speed Video Capillaroscopy
IRIBE Masaki, KURODA Hiroaki, NAKAMURA Yuki, MATSUBARA Mizuho, WATANABE Masao, SANADA Toshiyuki, バイオエンジニアリング講演会講演論文集, 2007, 20, 3, 4, 24 Jan. 2008
The Japan Society of Mechanical Engineers, JapanesePropagation of Nonlinear Wave in Liquid Containing Encapsulated Microbubbles
Kanagawa Tetsuya, Yano Takeru, Watanabe Masao, Fujikawa Shigeo, 日本流体力学会年会講演論文集, 2008, 306, 306, 2008
One-dimensional nonlinear waves in a liquid containing a number of spherical microbubbles are theoretically studied on the basis of a two-fluid model equations. The set of averaged equations consists of conservation laws of mass and momentum in gas and liquid phases, and the equation of motion of bubble wall. The compressibility of liquid phase is taken into account in the conservation laws and the equation of bubble wall motion, and this leads to the wave attenuation due to bubble oscillations. By using the method of multiple scales, Korteweg-de Vries-Burgers equation can be derived. The properties of the equation are discussed and compared to previous results based on different models on bubbly liquids., 日本流体力学会, Japanese門脈血行異常症に関する調査研究 バッドキアリ症候群機序解明のためのイメージベースドCFDによる流体力学的考察
橋爪誠, 渡部正夫, 松原瑞浦, 小西晃造, 門脈血行異常症調査研究班 平成19年度研究報告書, 34-36, 2008
JapaneseA215 High Speed Video Capillaroscopy and Image Analysis
KURODA Hiroaki, IRIBE Masaki, NAKAMURA Yuki, MATSUBARA Mizuho, SANADA Toshiyuki, WATANABE Masao, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2007, 18, 105, 106, 05 Oct. 2007
The Japan Society of Mechanical Engineers, JapaneseA218 Image-based CFD of blood flow field in the hepatic portion of the inferior vena cava on Budd-Chiari syndrome
MATSUBARA Mizuho, WATABANE Masao, WATANABE Satoshi, KONISHI Kozo, HASHIZUME Makoto, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2007, 18, 111, 112, 05 Oct. 2007
The Japan Society of Mechanical Engineers, JapaneseA209 Diffusion process and tissue development in cultured cartilage
KITAJIMA Yosuke, WATANABE Shohei, NOBAYASHI Makoto, SAWAE Yoshinori, MURAKAMI Teruo, WATABANE Masao, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2007, 18, 93, 94, 05 Oct. 2007
The Japan Society of Mechanical Engineers, Japanese医療と画像処理 高速度ビデオ毛細血管顕微鏡 非侵襲ヒト微小循環ループ内赤血球速度計測と血管形状認識
WATANABE MASAO, KURODA HIROAKI, IRIBE MASAKI, MATSUBARA MIZUHO, FURUE MASUTAKA, SANADA TOSHIYUKI, 画像ラボ, 18, 9, 59, 64, 01 Sep. 2007
日本工業出版, Japanese313 Segmentation and image-based CFD on Budd-Chiari syndrome
MATSUBARA Mizuho, WATABANE Masao, WATANABE Satoshi, KONISHI Kozo, HASHIZUME Makoto, バイオエンジニアリング講演会講演論文集, 2006, 19, 76, 77, 06 Jan. 2007
The Japan Society of Mechanical Engineers, Japanese601 Tissue development and transport phenomena in a regenerated cartilage
KITAJIMA Yousuke, SUGINO Shoichi, WATANABE Masao, SAWAE Yoshinori, SANADA Toshiyuki, MURAKAMI Teruo, バイオエンジニアリング講演会講演論文集, 2006, 19, 198, 199, 06 Jan. 2007
The Japan Society of Mechanical Engineers, Japanese234 On the image analysis of high-speed video capillaroscopy
KURODA Hiroaki, MATSUBARA Mizuho, IRIBE Masaaki, SANADA Toshiyuki, WATANABE Masao, バイオエンジニアリング講演会講演論文集, 2006, 19, 292, 293, 06 Jan. 2007
The Japan Society of Mechanical Engineers, Japaneseバッドキアリ症候群発症機序解明に向けた血管形状セグメンテーションとモデル構築
HASHIZUME MAKOTO, WATANABE MASAO, WATANABE SATOSHI, MATSUBARA MIZUHO, KONISHI KOZO, YAMAGUCHI SHOHEI, YOSHIDA DAISUKE, INAFUKU HITOSHI, KUNIYOSHI YUKIO, 門脈血行異常症調査研究班 平成18年度研究報告書, 29, 34, 2007
Japanese1607 Non-axisymmetric Bubble motion and Wake Structure(1)
ONO Tomoki, SANADA Toshiyuki, Sugihara Keiji, SHIROTA Minori, WATANABE Masao, Fluids engineering conference ..., 2006, "1607, a", 28 Oct. 2006
The Japan Society of Mechanical Engineers, Japanese1607 Non-axisymmetric Bubble motion and Wake Structure(2)
ONO Tomoki, SANADA Toshiyuki, Sugihara Keiji, SHIROTA Minori, WATANABE Masao, Fluids engineering conference ..., 2006, "1607, 1"-"1607-4", 28 Oct. 2006
Wake structure of zigzagging or spiraling motion of free rising bubbles was experimentally investigated. Single bubbles were generated in a silicone oil pooi and the wake structure was observed by using stereo high-speed video cameras. As results, a pair of vortex filaments, which is referred to as double-threaded type wake, was observed in the wake of a bubble rising in non-axisymmetry. Periodical generation of horse-shoe type vortices were observed when the bubbles rose with shape oscillations., The Japan Society of Mechanical Engineers, JapaneseG805 Shape and terminal velocity of a single bubble in superpurified water(2)
SUGIHARA Keiji, ONO Tomoki, SATO Ayaka, SHIROTA Minori, SANADA Toshiyuki, WATANABE Masao, Fluids engineering conference ..., 2006, "G805, 1"-"G805-4", 28 Oct. 2006
We experimentally studied the behavior of a single bubble in superpurified water. We developed the apparatus that can maintain the purity of water during the experiment. The apparatus is equipped with the measurement system for the resistance and TOC value of water so that we can quantitatively evaluate the purity of water. We investigated the critical Reynolds number over which the rising motion of bubble changed from rectangular to zigzag or spiral. We found out the critical Reynolds number was 660 for a bubble in superpurified water. We also compared the experimental results for terminal rise velocity and drag coefficient with the theoretical value for ellipsoidal bubble obtained in the limit of potential flow theory. For small bubbles, experimental values of the terminal velocity and drag coefficient were in good agreement with theoretical ones. For large bubbles, however, experimental values and theoretical ones had the relative deviation of about 8% in the terminal velocity and drag coefficient. This is because the bubble shape shows a deviation from fore-aft symmetry., The Japan Society of Mechanical Engineers, JapaneseG805 Shape and terminal velocity of a single bubble in superpurified water(1)
SUGIHARA Keiji, ONO Tomoki, SATO Ayaka, SHIROTA Minori, SANADA Toshiyuki, WATANABE Masao, Fluids engineering conference ..., 2006, "G805, a", 28 Oct. 2006
The Japan Society of Mechanical Engineers, Japanese306 High Speed Video Capillaroscopic Analysis of Human Capillary Vessel Blood Flow(1)
Watanabe Masao, Sanada Toshiyuki, Sawae Yoshinori, Matsubara Mizuho, Kuroda Hiroaki, Furue Masutaka, Fluids engineering conference ..., 2006, "306, a", 28 Oct. 2006
The Japan Society of Mechanical Engineers, Japanese306 High Speed Video Capillaroscopic Analysis of Human Capillary Vessel Blood Flow(2)
Watanabe Masao, Sanada Toshiyuki, Sawae Yoshinori, Matsubara Mizuho, Kuroda Hiroaki, Furue Masutaka, Fluids engineering conference ..., 2006, "306, 1"-"306-4", 28 Oct. 2006
Human blood flows are highly susceptible to physical and health conditions. Hence quantitative evaluation of blood flow helps the physical check up of individuals. However, the most convenient method is taking a blood sample, which can only examine ex vivo blood condition. We developed digital high speed video capillaroscopy to observe the capillary loops of blood vessels in the finger skin nail fold, of which blood flow can be easily visualized. We discuss the optimal selection of both light source and finger holder, in order to obtain images with both clearer contrast and less blur. We found that the combination of both the halogen light with focusing attachment and brush holder provides satisfactory results with qualitative evaluation by using image processing tools of MATLAB., The Japan Society of Mechanical Engineers, JapaneseHow far does wind force go? 19) Support of CFD to wind turbine performance measurement.
SHIROTA NO, SANADA TOSHIYUKI, MATSUSHITA DAISUKE, HARA YOSHINORI, WATANABE MASAO, MATSUMIYA HIKARU, ターボ機械, 34, 9, 568, 571, 10 Sep. 2006
日本工業出版, JapaneseD23 Measurements of Wind Velocity into a Wind Turbine on Complex Terrain with CFD
SHIROTA Minori, FUJINO Masatoshi, SANADA Toshiyuki, WATANABE Masao, MATSUMIYA Hikaru, 日本機械学会九州支部講演論文集, 2006, 59, 105, 106, Mar. 2006
The Japan Society of Mechanical Engineers, JapaneseD14 Bubble Wake Visualization by using Photochromic Dye
ONO Tomoki, SATO Shinsuke, SHIROTA Minoro, SANADA Toshiyuki, WATANABE Masao, 日本機械学会九州支部講演論文集, 2006, 59, 97, 98, Mar. 2006
The Japan Society of Mechanical Engineers, Japanese305 Blood flow simulation on Budd-Chiari syndrome
MATSUBARA Mizuho, WATABANE Masao, WATANABE Satoshi, HASHIZUME Makoto, KONISHI Kozo, バイオエンジニアリング講演会講演論文集, 2005, 18, 147, 148, 12 Jan. 2006
The Japan Society of Mechanical Engineers, Japanese214 Visualization of tissue structure and transport phenomena in regenerated articular cartilage
SUGINO Shouichi, HAARI Kenta, WATANABE Masao, SAWAE Yoshinori, SANADA Toshiyuki, MURAKAMI Teruo, バイオエンジニアリング講演会講演論文集, 2005, 18, 87, 88, 12 Jan. 2006
The Japan Society of Mechanical Engineers, Japanese医用画像解析及び流体力学的手法によるバッドキアリ症候群発症機序の解明
WATANABE MASAO, MATSUBARA MIZUHO, WATANABE SATOSHI, KONISHI KOZO, YAMAGUCHI SHOHEI, HASHIZUME MAKOTO, INAFUKU HITOSHI, KUNIYOSHI YUKIO, 門脈血行異常症調査研究班 平成17年度研究報告書, 36, 41, 2006
JapanesePreliminary experience with minimally invasive video-assisted surgery for thymic diseases, including myasthenia gravis, through a horizontal ministernotomy
M Watanabe, R Yozu, K Kobayashi, JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY, 130, 3, 912, +, Sep. 2005
English, Others1015 Bouncing and Coalescence of a pair of Bubbles Rising Side by Side
SUGIHARA Keiji, SATO Shinsuke, SANADA Toshiyuki, WATANABE Masao, FUKANO Tohru, 日本機械学会九州支部講演論文集, 2005, 58, 387, 388, Mar. 2005
The Japan Society of Mechanical Engineers, Japanese901 On the boundary condition of lattice Boltzmann Method
UEZONO Daisuke, SANADA Toshiyuki, WATANABE Masao, MATSUKUMA Yosuke, 日本機械学会九州支部講演論文集, 2005, 58, 323, 324, Mar. 2005
The Japan Society of Mechanical Engineers, JapaneseBehavior of a pair of bubbles rising side by side
SANADA Toshiyuki, SATO Shinsuke, WATANABE Masao, FUKANO Tohru, Fluids engineering conference ..., 2004, 293, 293, 24 Nov. 2004
The Japan Society of Mechanical Engineers, JapaneseIn Vivo Analysis of Human Capillary Vessel Blood Flow and Vessel Shape
Watanabe Masao, Sanada Toshiyuki, Sawae Yoshinori, Furue Masutaka, Fluids engineering conference ..., 2004, 86, 86, 24 Nov. 2004
The Japan Society of Mechanical Engineers, JapaneseStudy on Adsorption on Gas Liquid Interface by Totao Internal Relection Fluorescence
Watanabe Masao, Sawae Yoshinori, Sanada Toshiyuki, Yotsumoto Kiyoshi, Murakami Teruo, Fluids engineering conference ..., 2004, 88, 88, 24 Nov. 2004
The Japan Society of Mechanical Engineers, JapaneseEffects of Chondrocyte Activity on Macro-Scale Transport Phenomena in Regenerated Articular Cartilage Tissue
Watanabe Masao, Sawae Yoshinori, Haari Kenta, Sanada Toshiyuki, Mizuno Shuichi, Murakami Teruo, Fluids engineering conference ..., 2004, 85, 85, 24 Nov. 2004
The Japan Society of Mechanical Engineers, JapaneseContour Segmentation of Three Dimensional Image Using Level Set Method
WATANABE Masao, バイオエンジニアリング講演会講演論文集, 2004, 16, 159, 160, 21 Jan. 2004
The Japan Society of Mechanical Engineers, JapaneseBehaviors of two bubbles rising side by side
NODA Hitomi, SANADA Toshiyuki, WATANABE Masao, FUKANO Tohru, 日本機械学会九州支部講演論文集, 2003, 139, 140, 30 Oct. 2003
The Japan Society of Mechanical Engineers, JapaneseBubble Behaviors and Liquid Flow Structures in Single Bubble Chain : Liquid Jet Development by Single Bubble
SANADA Toshiyuki, WATANABE Masao, FUKANO Tohru, Fluids engineering conference ..., 2003, 21, 21, 18 Sep. 2003
The Japan Society of Mechanical Engineers, JapaneseLevel Set Based Integration of Segmentation and Computational Fluid Dynamics for Flow Correction in Phase Contrast Angiography.
Masao Watanabe, Ron Kikinis,Carl-Fredrik Westin, Medical Image Computing and Computer-Assisted Intervention - MICCAI 2002, 5th International Conference, Tokyo, Japan, September 25-28, 2002, Proceedings, Part II, 10, 405, 412, 2002, [Peer-reviewed]
Springer416 Effect of generation frequency and bubble diameter on the behavior of single bubble train
SANADA Toshiyuki, WATANABE Masao, FUKANO Tohru, 日本機械学会九州支部講演論文集, 2001, 145, 146, 12 Oct. 2001
The Japan Society of Mechanical Engineers, JapaneseExperimental Study on Contact and Coalescence of a Pair of Bubbles under Micro Gravity Conditons.
WATANABE MASAO, ONIZUKA RYUJI, FUKANO TOORU, 九州大学工学集報, 74, 3, 199, 206, 30 May 2001
Kyushu University, Japanese機械工学年鑑(1999年)流体工学 1. まえがき 2. 非圧縮流れ 3. 圧縮性流れ 4. 混相流 5. 流体機械要素 6. 特殊流体 7. 流体計測 8. 数値流体力学 9. 油空圧技術 10. 水力機械 11. 空気機械
深野 徹, 西 道弘, 田中 和博, 高曽 徹, 宮里 義昭, 青木 俊之, 佐田富 道雄, 富田 侑嗣, 渡邉 聡, 塚本 寛, 児玉 好雄, 大庭 英樹, 半田 太郎, 青木 俊之, 半田 太郎, 益田 光治, 片野田 洋, 益田 光治, 速水 洋, 古川 雅人, 渡部 正夫, 古川 明徳, 井戸 章雄, 坂元 篤, 村井 謙介, 伊高 英彦, 高津 恭, 日本機械学会論文集. B編, 66, 648, 1922, 1935, 25 Aug. 2000
"6･4 希薄流体 / 片野田洋, 益田光治 ", 日本機械学会, JapaneseReport of The 2nd Organized Multiphase Flow Forum'98-Fukuoka : New EFD for Multiphase Flow
MURAI Yuichi, WATANABE Masao, HOSOKAWA Shigeo, FUJIKAWA Shigeo, 混相流 = Japanese journal of multiphase flow, 13, 1, 61, 62, 15 Mar. 1999
JapaneseOscillation-Induced Heat-Transport (Thermoacoustic) Phenomena and Its Application to Thermal Equipments. Linear and Nonlinear Processes in Thermoacoustic Prime Movers. Research Topics in United States.
WATANABE MASAO, 伝熱研究, 36, 142, 69, 72, Jul. 1997
日本伝熱学会, JapaneseNumerical simulation on a bubble motion with full N-S equations.
MATSUMOTO YOICHIRO, WATANABE MASAO, TAKEMURA FUMIO, 東京大学工学部総合試験所年報, 47, 47, 167, 172, Sep. 1988
東京大学工学部総合試験所, JapaneseNonlinear oscillation of gas bubble with consideration of internal condition.
MATSUMOTO YOICHIRO, WATANABE MASAO, 東京大学工学部総合試験所年報, 46, 46, 263, 268, Sep. 1987
東京大学工学部総合試験所, JapaneseLectures, oral presentations, etc.
- 気液界面における速度分布関数の非平衡性が蒸気の流れに与える影響
KON MISAKI, KOBAYASHI KAZUMICHI, WATANABE MASAO
日本物理学会講演概要集(CD-ROM), 24 Mar. 2015, Japanese - 生体光イメージングのためのヒト頸部内光伝播モデルの構築
FUJII HIROYUKI, OKAWA SHIMPEI, NADAMOTO KEN, OKADA EIJI, YAMADA YUKIO, HOSHI YOKO, WATANABE MASAO
バイオエンジニアリング講演会講演論文集, 08 Jan. 2015, Japanese - アルゴン‐ネオン二成分系における気体論境界条件に関する分子動力学シミュレーション
SASAKI KIYOFUMI, KON MISAKI, KOBAYASHI KAZUMICHI, FUJII HIROYUKI, WATANABE MASAO
数値流体力学シンポジウム講演論文集(CD-ROM), 2015, Japanese - 平均場運動論に基づく非平衡蒸発・凝縮下の気液界面における蒸発流束の評価
KON MISAKI, KOBAYASHI KAZUMICHI, WATANABE MASAO
混相流シンポジウム講演論文集(CD-ROM), 2015, Japanese - 真空容器内での高速液滴衝突により発生する液膜流れの観察
KATO MASAYA, YAMAGUCHI YOHEI, KOBAYASHI KAZUMICHI, WATANABE MASAO
混相流シンポジウム講演論文集(CD-ROM), 2014, Japanese - エタノール液滴と固体壁の衝突における周囲雰囲気の影響
SASAGAWA YUUMA, WATANABE MASAO, KOBAYASHI KAZUMICHI
混相流シンポジウム講演論文集(CD-ROM), 2014, Japanese - 縮小・拡大ノズルを用いた液滴噴霧洗浄法に関する数値解析
SAITO IKKI, KAWAHARA JUN'YA, KOBAYASHI KAZUMICHI, WATANABE MASAO
混相流シンポジウム講演論文集(CD-ROM), 2014, Japanese - ナノ液滴の衝突によって発生する液膜流れに関する分子動力学計算
KONNO KAZUKI, FUJII HIROYUKI, KOBAYASHI KAZUMICHI, WATANABE MASAO
数値流体力学シンポジウム講演論文集(CD-ROM), 2014, Japanese - 非平衡気液界面における気体論境界条件の液体温度依存性に関する数値解析
KON MISAKI, KOBAYASHI KAZUMICHI, WATANABE MASAO
数値流体力学シンポジウム講演論文集(CD-ROM), 2014, Japanese - Enskog‐Vlasov方程式による気液界面の気体論境界条件に関する数値シミュレーション
KOBAYASHI KAZUMICHI, KON MISAKI, OHASHI KOTARO, WATANABE MASAO
日本機械学会年次大会講演論文集(CD-ROM), 07 Sep. 2013, Japanese - アルゴン‐ネオン系におけるアルゴン液体の蒸発に関する分子動力学解析
HORI KAZUMASA, YAHAGI TAKATO, TAKEUCHI SHINNOSUKE, YAGUCHI HISAO, KOBAYASHI KAZUMICHI, WATANABE MASAO
日本機械学会年次大会講演論文集(CD-ROM), 07 Sep. 2013, Japanese - Enskog‐Vlasov方程式による温度差のある二液膜を用いた非平衡蒸発・凝縮現象の数値解析
KON MISAKI, KOBAYASHI KAZUMICHI, WATANABE MASAO
日本物理学会講演概要集, 26 Aug. 2013, Japanese - 分子気体論に基づく相変化を伴う気液界面境界条件の流体力学解析への適用手法の検討
JIMBO YOSHINORI, KOBAYASHI KAZUMICHI, WATANABE MASAO
数値流体力学シンポジウム講演論文集(CD-ROM), 2013, Japanese - 固体壁への液滴の衝突により発生するスプラッシュ形成過程の観察
NISHIZAWA HIROKI, KATO MASAYA, UEMURA RYOICHI, KOBAYASHI KAZUMICHI, WATANABE MASAO, SANADA TOSHIYUKI
混相流シンポジウム講演論文集(CD-ROM), 2013, Japanese - 衝撃波管実験と分子気体力学解析による広範囲の非平衡凝縮状態におけるエタノール蒸気の凝縮係数に関する研究
WATANABE YUSUKE, KATAHIRA KEISUKE, KOBAYASHI KAZUMICHI, WATANABE MASAO
混相流シンポジウム講演論文集(CD-ROM), 2013, Japanese - 縮小・拡大ノズル内を加速する液滴噴霧流の数値シミュレーション
SAITO IKKI, KAWAHARA JUN'YA, TAMURA TOSHIYUKI, KOBAYASHI KAZUMICHI, WATANABE MASAO
混相流シンポジウム講演論文集(CD-ROM), 2013, Japanese - 平均場運動論による温度の異なる2つの液膜間での定常蒸発・凝縮の数値計算
KON MISAKI, KOBAYASHI KAZUMICHI, WATANABE MASAO
日本伝熱シンポジウム講演論文集(CD-ROM), 2013, Japanese - 洗浄用ノズル内の高速液滴噴霧流の数値解析
TAMURA TOSHIYUKI, KAWAHARA JUN'YA, KOBAYASHI KAZUMICHI, WATANABE MASAO
日本機械学会北海道支部講演会講演概要集, 20 Oct. 2012, Japanese - 平均場運動理論に基づく非平衡凝縮現象の数値シミュレーション
OHASHI KOTARO, KOBAYASHI KAZUMICHI, WATANABE MASAO
数値流体力学シンポジウム講演論文集(CD-ROM), 2012, Japanese - J054032 Molecular Gas Dynamics on Resonant Gas Oscillations Accompanied with Phase Changes at Vapor-Liquid Interface
INABA Masashi, YANO Takeru, WATANABE Masao, KOBAYASHI Kazumichi, FUJIKAWA Shigeo
Mechanical Engineering Congress, Japan, 11 Sep. 2011, Japanese
The resonant gas oscillation excited in a one-dimensional space between an oscillating plate and a planer surface of a thin liquid layer on a quiescent rigid-wall is considered. Vapor flows with evaporation or condensation at the vapor-liquid interface are theoretically studied on the basis of a polyatomic version of Gaussian-BGK Boltzmann equation with a kinetic boundary condition including an evaporation coefficient. - J054033 Numerical Simulations for Couette flows in Dense Gas Based on Enskog Equation
KOBAYASHI Kazumichi, OHASHI Kotarou, INABA Masashi, WATANABE Masao, FUJIKAWA Shigeo
Mechanical Engineering Congress, Japan, 11 Sep. 2011, Japanese
Numerical simulations for Couette flows in a dense gas are conducted based on the Enskog equation. In order to solve the Enskog equation, we use the particle scheme method, which is an extension of the well known DSMC method that is used to solve the Boltzmann equation. The results agree well with the solution of the Boltzmann equation, as the ratio of molecular diameter to the mean free path of the molecules, a/ A, becomes smaller. A thin layer is formed near a solid wall surface as the ratio al A becomes larger. We also find that the slip velocity on the solid surface depends on the ratio al A. - J054031 Measurements of the Evaporation Coefficient of Water Using Sound Resonance Method
NAKAMURA Shigeto, YANO Takeru, KOBAYASHI Kazumichi, WATANABE Masao, FUJIKAWA Shigeo
Mechanical Engineering Congress, Japan, 11 Sep. 2011, Japanese
We propose a new method for measurement of the evaporation coefficient using sound resonance experiment based on a theory of molecular gas dynamics. The evaporation coefficient is one of the parameters contained in the kinetic boundary condition. The evaporation coefficient of water is determined from the pressure amplitude of resonant sound wave in a cylindrical space bounded by a sound source and a vapor-liquid interface. By comparing the pressure amplitude with a linear theory based on molecular gas dynamics, we prove that the evaporation coefficient of water is about 1.0 around 300K. - Enskog方程式を用いた高密度気体のCouette流れに関する数値計算
小林一道, 大橋広太郎, 稲葉匡司, 渡部正夫, 藤川重雄
日本機械学会年次大会講演論文集, 10 Sep. 2011, Japanese - 8I-11 Material transport and tissue development in engineered cartilage model culture under cyclic compression
SAWAE Yoshinori, WATANABE Masao, OMATA Seiji, MURAKAMI Teruo
バイオエンジニアリング講演会講演論文集, 07 Jan. 2011, Japanese - 圧縮負荷を受ける再生軟骨モデル内の物質輸送と組織形成
SAWAE YOSHINORI, WATANABE MASAO, OMATA SEIJI, MURAKAMI TERUO
バイオエンジニアリング講演会講演論文集, 07 Jan. 2011, Japanese - 403 Human Nailfold Capillary Shape Analysis and Red Blood Cell Velocity Measurement
佐野 宏典, 矢口 久雄, 小林 一道, 渡部 正夫, 藤川 重雄
北海道支部講演会講演概要集, 07 Nov. 2010, Japanese - ヒト爪郭部毛細血管の形状解析および赤血球の速度測定
SANO HIRONORI, YAGUCHI HISAO, KOBAYASHI KAZUMICHI, WATANABE MASAO, FUJIKAWA SHIGEO
日本機械学会北海道支部講演会講演概要集, 07 Nov. 2010, Japanese - 0407 Nonlinear Waves in Liquid Containing Microbubbles Encapsulated by Visco-Elastic Shell
KANAGAWA Tetsuya, WATANABE Masao, YANO Takeru, FUJIKAWA Shigeo
Fluids engineering conference ..., 29 Oct. 2010, Japanese
Nonlinear propagation of pressure waves in an initially quiescent liquid containing non-uniformly distributed spherical microbubbles is theoretically studied on the basis of the method of multiple scales. We focus on almost unidirectional waves propagating mainly in one direction with a weak diffraction or weak focusing to the transverse direction (like a ultrasound beam). Based on a methodology recently proposed by the authors, the KZK type equation, in which the dispersion and the non-uniformity of number density of bubbles are considered, is derived from the basic equations of bubbly flows. - 303 マイクロ液滴噴霧洗浄技術開発のための高速ノズル流動解析(OS3. ナノ・マイクロ熱流動現象(1),オーガナイズドセッション講演)
高橋 広樹, 渡部 正夫, 小林 一道, 藤川 重雄
計算力学講演会講演論文集, 23 Sep. 2010, Japanese - 302 壁面に衝突する高速マイクロ液滴挙動に及ぼす液滴温度の効果(OS3. ナノ・マイクロ熱流動現象(1),オーガナイズドセッション講演)
ユ ヨンゼ, 渡部 正夫, 小林 一道, 藤川 重雄
計算力学講演会講演論文集, 23 Sep. 2010, Japanese - 301 Evaluation of Evaporation Coefficient at Spherical Vapor-Liquid Interface of Nanodroplet
矢口 久雄, 矢野 猛, 渡部 正夫, 藤川 重雄
The Computational Mechanics Conference, 23 Sep. 2010, Japanese - ナノ液滴の球面状気液界面における蒸発係数の評価
YAGUCHI HISAO, YANO TAKERU, WATANABE MASAO, FUJIKAWA SHIGEO
日本機械学会計算力学講演会論文集(CD-ROM), 22 Sep. 2010, Japanese - 壁面に衝突する高速マイクロ液滴挙動に及ぼす液滴温度の効果
YU YONZE, WATANABE MASAO, KOBAYASHI KAZUMICHI, FUJIKAWA SHIGEO
日本機械学会計算力学講演会論文集(CD-ROM), 22 Sep. 2010, Japanese - マイクロ液滴噴霧洗浄技術開発のための高速ノズル流動解析
TAKAHASHI HIROKI, WATANABE MASAO, KOBAYASHI KAZUMICHI, FUJIKAWA SHIGEO
日本機械学会計算力学講演会論文集(CD-ROM), 22 Sep. 2010, Japanese - Novel Method for Measurement of Evaporation Coefficient
Nakamura Shigeto, Yano Takeru, Kobayashi Kazumichi, Watanabe Masao, Fujikawa Shigeo
Proceedings, ... meeting of Japan Society of Fluid Mechanics, 09 Sep. 2010, Japanese
We propose a new method for measurement of the evaporation coefficient using nonlinear sound resonance experiment based on a theory of molecular gas dynamics. The evaporation coefficient is determined from the pressure amplitude of second harmonics generated by the nonlinear effect of resonant sound wave in a cylindrical space bounded by a sound source and a gas-liquid interface. To demonstrate the applicability of this method, we conduct a test experiment. As a result, we confirm the increase of second harmonics amplitude caused by the sound resonance. - Weakly Nonlinear Propagation of Sound Beam in Bubbly Liquids
KANAGAWA Tetsuya, WATANABE Masao, YANO Takeru, FUJIKAWA Shigeo
Proceedings, ... meeting of Japan Society of Fluid Mechanics, 09 Sep. 2010, Japanese
Weakly nonlinear propagation of pressure waves in an initially quiescent liquid containing many small spherical gas bubbles is studied for the case of low frequency and long wavelength. We focus on almost unidirectional waves propagating mainly in one direction with a weak diffraction to the transverse direction (like a ultrasound beam), i.e., weakly two-dimensional waves. On the basis of a methodology recently proposed by ourselves, the KZK equation with a dispersion term is systematically derived from the basic equations of bubbly flows. - Evaporation Coefficient at a Spherical Vapor-Liquid Interface
Yaguchi Hisao, Yano Takeru, Watanabe Masao, Fujikawa Shigeo
Proceedings, ... meeting of Japan Society of Fluid Mechanics, 09 Sep. 2010, Japanese
Kinetics of phase change at spherical interface between an argon nanodroplet and its vapor is studied by molecular dynamics simulation. The evaporation coefficient is evaluated at spherical control surface around the nanodroplet at 85K, however it depends on not only a radius of the nanodroplet but also that of control surface. Thus we define a new specific control surface, where the mass flux of evaporating molecules from the nanodroplet into vacuum is equal to that from the planar liquid film. The specific surface is found to be in a few nanometers distance from the center of the vapor-liquid transition layer. We adopt this surface as a interface for evaluating evaporation coefficient and successfully determine the evaporation coefficients for argon nanodroplets ranging from 1 to 4nm in radius. As a result, the evaporation coefficient decreases with decreasing in the radius of the nanodroplet. - Weakly Nonlinear Analysis for Resonant Gas Oscillations with Evaporation and Condensation
Inaba Masashi, Yano Takeru, Watanabe Masao, Kobayashi Kazumichi, Fujikawa Shigeo
Proceedings, ... meeting of Japan Society of Fluid Mechanics, 09 Sep. 2010, Japanese
The behavior of resonant sound waves in a finite one-dimensional space between an oscillating plate (sound source) and a vapor-liquid interface is analyzed by applying the asymptotic theory for Kn<S0507-1-2 Shock-Tube-Deduced Condensation Coefficients of Water and Methanol Vapors near Equilibrium States : Boltzmann-Equation-Assisted Data Analysis
MOURI Shingo, OGASAWARA Toshiki, YAGUCHI Hisao, WATANABE Masao, FUJIKAWA Shigeo
年次大会講演論文集 : JSME annual meeting, 04 Sep. 2010, Japanese
The condensation coefficients of water and methanol, i.e., the ratios of condensation mass flux of vapor molecules to their mass flux colliding on the interface, are evaluated by combining the experiment conducted by a shock tube and the numerical simulation of Gaussian-BGK Boltzmann equation applicable to polyatomic gases. Film condensation occurs on the endwall of vapor filled shock-tube, when a shock wave is reflected at the endwall and the vapor eventually becomes supersaturated there. The formed liquid film grows with the lapse of time. The time evolution in thickness of the liquid film is measured by an optical interferometer, and thereby the growth rate of the film is obtained. The rate is incorporated into the kinetic boundary condition at the interface for the Gaussian-BGK Boltzmann equation, the solution of which is in consequence obtained uniquely. The condensation coefficients in nearequilibrium states for water and methanol are found to be close to those evaluated by molecular dynamics simulations at equilibrium states.S0507-1-1 Nonequilibrium Molecular Dynamics Simulation of Evaporation and Condensation of Nanodroplet
YAGUCHI Hisao, YANO Takeru, WATAnABE Masao, FUJIKAWA Shigeo
年次大会講演論文集 : JSME annual meeting, 04 Sep. 2010, Japanese
Nonequilibrium molecular dynamics simulation is carried out to study weak condensation of argon vapor into its nanodroplet. Temperature of the nanodroplet is kept at 90 K by using the velocity scaling method. The nanodroplet grows steadily ranging from about 3.3 to 3.4 nm in the radius R_m which is defined as the radius of the center of transition layer in density profile. The mass fluxes at the vapor-nanodroplet interface are investigated and condensation coefficient of the nanodroplet is successfully determined. As a result, the condensation coefficient is almost equal to the evaporation coefficient obtained by our previous study. The rate of change of R_m can be predicted by the mass fluxes and evaporation/condensation coefficients within about 16 percent error.ナノ液滴の蒸発・凝縮に関する非平衡分子動力学シミュレーション
YAGUCHI HISAO, YANO TAKERU, WATANABE MASAO, FUJIKAWA SHIGEO
日本機械学会年次大会講演論文集, 04 Sep. 2010, Japanese衝撃波管実験とボルツマン方程式解析による平衡状態近傍での水蒸気およびメタノール蒸気の凝縮係数決定
MORI SHINGO, OGASAWARA TOSHIKI, YAGUCHI HISAO, WATANABE MASAO, FUJIKAWA SHIGEO
日本機械学会年次大会講演論文集, 04 Sep. 2010, Japanese気泡を含む液体中における圧力波の非線形解析
KANAGAWA TETSUYA, YANO TAKERU, WATANABE MASAO, FUJIKAWA SHIGEO
日本混相流学会年会講演会講演論文集, Jul. 2010, Japanese水蒸気・水混合噴流低環境負荷洗浄法によるドライエッチング残渣除去
WATANABE MASAO, SANADA TOSHIYUKI, MASHIKO TAKASHI, SEKI AKIKO, HAYASHIDA ATSUSHI
日本混相流学会年会講演会講演論文集, Jul. 2010, Japanese蒸発・凝縮をともなう共鳴音波に関する数値解析
INABA MASASHI, YOSHINAKA RINTARO, WATANABE MASAO, FUJIKAWA SHIGEO, YANO TAKERU
日本混相流学会年会講演会講演論文集, Jul. 2010, Japanese水蒸気・水混合噴流の物理力の実験的評価
MASHIKO TAKASHI, HAYASHIDA ATSUSHI, SANADA TOSHIYUKI, WATANABE MASAO
日本混相流学会年会講演会講演論文集, Jul. 2010, Japanese気泡後部トロイダル渦の抗力への寄与
SHIROTA MINORI, SATO AYAKA, SANADA TOSHIYUKI, WATANABE MASAO
日本混相流学会年会講演会講演論文集, Jul. 2010, Japanese非線形共鳴音波による水の蒸発係数測定
NAKAMURA SHIGETO, INABA MASASHI, WATANABE MASAO, FUJIKAWA SHIGEO, YANO TAKERU
理論応用力学講演会講演論文集, 08 Jun. 2010, Japanese蒸発・凝縮をともなう非線形音波に関する分子気体力学解析
INABA MASASHI, YANO TAKERU, WATANABE MASAO, FUJIKAWA SHIGEO
理論応用力学講演会講演論文集, 08 Jun. 2010, Japanese粘弾性殻付き気泡を含む液体中における非線形波動
KANAGAWA TETSUYA, WATANABE MASAO, YANO TAKERU, FUJIKAWA SHIGEO
日本機械学会流体工学部門講演会講演論文集(CD-ROM), 2010, Japanese206 Development of Low-pressure Submerged Water Jet for Organic Compounds Decomposition
中村 謙介, 渡部 正夫, 藤川 重雄
北海道支部講演会講演概要集, 28 Nov. 2009, Japanese有機化合物分解用低圧水中ウォータージェットの開発
NAKAMURA KENSUKE, WATANABE MASAO, FUJIKAWA SHIGEO
日本機械学会北海道支部講演会講演概要集, 28 Nov. 2009, Japanese1605 Visualization of Nailfold Micro-circulation Using High-speed Video Capillaroscopy
WATANABE Masao, NAKAMURA Yuuki, SANO Hironori, YAGUCHI Hisao
Fluids engineering conference ..., 06 Nov. 2009, Japanese
Capillaroscopy is a "lens" that is able to observe capillary loops of blood vessels in the human finger skin nail fold, of which blood flow can be easily visualized, and has been long used for clinical diagnosis. We have been developing digital high speed video capillaroscopy by integrating to high-speed high-sensitivity video camera with deep-focus zoom lens. We discuss quantitative evaluation of blood velocity in both arteriol and venule of human nailfold microcirculation, using two different methods, namely, plasma gap tracking method and fixed point observation method with correlation.T0501-2-5 Molecular Dynamics Analysis of Temperature Change in Nanodroplet Evaporating into Vacuum
YAGUCHI Hisao, TANAKA Ryoichi, YANO Takeru, WATANABE Masao, FUJIKAWA Shigeo
年次大会講演論文集 : JSME annual meeting, 12 Sep. 2009, Japanese
Molecular dynamics simulations of an argon nanodroplet evaporating into vacuum are carried out to investigate time development of its temperature. Configuration in vaporliquid equilibrium state of the nanodroplet with 3.6 nm in radius at 105 K is adopted as initial configuration of the evaporation. Although the temperature of nanodroplet decreases with time because of the loss of latent heat for evaporation, rapid temperature rise has been observed at about 8.0 ns. Radial distribution function of molecules inside the nanodroplet suggests that phase change from liquid to solid has been occurred. Recovery from the supercooling consequent to release of latent heat for solidification is thought to be cause of this rapid temperature rise.T0501-2-4 Evaluation of Condensation Coefficient of Water in Near-equilibrium State by Shock Tube and Molecular Gas Dynamics
OGASAWARA Toshiki, YAMANO Daigo, WATANABE Masao, FUJIKAWA Shigeo
年次大会講演論文集 : JSME annual meeting, 12 Sep. 2009, Japanese
The condensation coefficient of water, ie., the ratio of condensation mass flux of vapor molecules to incoming mass flux at the interface, is evaluated by combining the experiment conducted by a shock tube and the numerical simulation of Gaussian-BGK Boltzmann equation applicable to polyatomic gases. Film condensation occurs on the endwall of a vaporfilled shock-tube, when a shock wave is reflected at the endwall and the vapor becomes supersaturated there. The formed liquid film grows with the lapse of time. The time evolution in thickness of the liquid film is measured by an optical interferometer, and thereby the growth rate of the film is obtained. The rate is incorporated into the kinetic boundary condition at the interface for the Gaussian-BGK Boltzmann equation, and the unique numerical solution of the vaporliquid system is obtained. Values of condensation coefficient in near equilibrium state are found to be close to that evaluated by molecular dynamics simulations at the equilibrium state.J0201-1-6 Acoustic Characteristics of Ultrasound Propagating in Liquid Containing Lipid Bubbles
IMAI Ryosuke, NAKAGAWA Hiroya, SAKURAI Kousuke, WATANABE Masao, FUJIKAWA Shigeo
年次大会講演論文集 : JSME annual meeting, 12 Sep. 2009, Japanese
In the field of medical engineering, the application of bubbles of nanometer size to Drug Delivery System (DDS) has attracted great attention as the administration of next generation. DDS with bubbles is expected to be a noninvasive clinical treatment. As the transport carrier of DDS, there exists bubble encapsulated in a lipid bilayer, generally called as a lipid bubble. However, dynamic properties of these lipid bubbles are not yet made clear. In this study, acoustic characteristics of lipid bubbles are experimentally investigated. The resonant frequencies of lipid bubbles are evaluated from attenuation of ultrasound pulse propagating through the experimental cell filled with lipid bubble solution. It is found that the attenuation spectrum has two dominant peaks in the frequency range of 1.0 through 14.0 MHz due to the acoustic energy absorbed by lipid bubble with resonant oscillations.Acoustic Characteristics of Ultrasound Propagating in Liquid Containing Lipid Bubbles
IMAI RYOSUKE, NAKAGAWA HIROYA, SAKURAI KOSUKE, WATANABE MASAO, FUJIKAWA SHIGEO
日本機械学会年次大会講演論文集, 12 Sep. 2009, JapaneseEvaluation of Condensation Coefficient of Water in Near-equilibrium State by Shock Tube and Molecular Gas Dynamics
OGASAWARA TOSHIKI, YAMANO DAIGO, WATANABE MASAO, FUJIKAWA SHIGEO
日本機械学会年次大会講演論文集, 12 Sep. 2009, JapaneseMolecular Dynamics Analysis of Temperature Change in Nanodroplet Evaporating into Vacuum
YAGUCHI HISAO, TANAKA RYOICHI, YANO TAKERU, WATANABE MASAO, FUJIKAWA SHIGEO
日本機械学会年次大会講演論文集, 12 Sep. 2009, JapaneseEvaluation of Evaporation Coefficient at the Vapor-liquid Interface of Argon Nanodroplet by Molecular Dynamics Method
Yaguchi Hisao, Yano Takeru, Watanabe Masao, Fujikawa Shigeo
Proceedings, ... meeting of Japan Society of Fluid Mechanics, 02 Sep. 2009, Japanese
Mass fluxes and evaporation coefficients at the interface between an argon nanodroplet and its vapor are investigated by nonequilibrium molecular dynamics (MD) simulations. The simulations are carried out at the temperatures of 85, 90, 95, 100, and 105K with droplet radii ranging from about 1nm to 4nm. The evaporation mass fluxes J_are obtained by MD simulations of evaporation into vacuum and are found to be almost independent of droplet radius at the specified control surface R_ . Since the outgoing mass flux J_ in an equilibrium state becomes large as the droplet radius does small, the evaporation coefficient α_e, defined by the ratio of J_ to J_ , decreases with decrease in the droplet radius. Weakly Nonlinear Propagation of Quasi-Monochromatic Waves in Bubbly Liquids
Kanagawa Tetsuya, Yano Takeru, Watanabe Masao, Fujikawa Shigeo
Proceedings, ... meeting of Japan Society of Fluid Mechanics, 02 Sep. 2009, Japanese
One-dimensional nonlinear dispersive waves in a liquid containing a number of small spherical gas bubbles are theoretically studied based on a set of two-fluid averaged equations composed of the conservation laws of mass and momentum for gas and liquid phases, and the Keller equation for the bubble dynamics. The liquid compressibility is taken into account, and this leads to the wave attenuation due to bubble oscillations. By using an appropriate scaling of physical parameters and the method of multiple scales, we can derive the nonlinear Schrodinger equation with an attenuation term due to the acoustic radiation and the liquid viscosity. This equation describes a far field of a quasi-monochromatic wave train in the bubbly liquid, which evolves into a slowly modulated wave packet as a result of long range propagation of weakly nonlinear waves with the strong dispersion effect.Molecular Gas Dynamics on Resonant Sound Waves Excited in One-Dimensional Space between Oscillating Plate and Vapor-Liquid Interface
INABA Masashi, YANO Takeru, WATANABE Masao, FUJIKAWA Shigeo
Proceedings, ... meeting of Japan Society of Fluid Mechanics, 02 Sep. 2009, Japanese
The behavior of resonant sound waves in a finite one-dimensional space between an oscillating plate (sound source) and a vapor-liquid interface is analyzed by applying the asymptotic theory for Kn<30aTJ-5 Molecular Dynamics Study of Vapor-liquid Equilibrium Condition of Nanodroplet
Yaguchi Hisao, Yano Takeru, Watanabe Masao, Fujikawa Shigeo
Meeting abstracts of the Physical Society of Japan, 03 Mar. 2009, Japanese超微小液滴の気液平衡条件に関する分子動力学的研究
YAGUCHI HISAO, YANO TAKERU, WATANABE MASAO, FUJIKAWA SHIGEO
日本物理学会講演概要集, 03 Mar. 2009, Japanese508 Transport Phenomena in Scaffold Gel for Engineered Cartilage
NOBAYASHI Makoto, WATANABE Shouhei, NODA Hiroyuki, SAWAE Yoshinori, WATANABE Masao
バイオエンジニアリング講演会講演論文集, 22 Jan. 2009, Japanese318 Noninvasive Observation of Red Blood Cell Dynamics with High Speed Digital Video Capillaroscopy
NAKAMURA Yuuki, IRIBE Masaki, MATSUBARA Mizuho, WATANABE Masao
バイオエンジニアリング講演会講演論文集, 22 Jan. 2009, Japanese再生軟骨担体ゲル内での物質輸送現象
NOBAYASHI MAKOTO, WATANABE SHOHEI, NODA HIROYUKI, SAWAE YOSHINORI, WATANABE MASAO
バイオエンジニアリング講演会講演論文集, 22 Jan. 2009, Japanese高速度ビデオ毛細血管顕微鏡を用いた非侵襲赤血球動態観察
NAKAMURA YUKI, IRIBE MASAKI, MATSUBARA MIZUHO, WATANABE MASAO
バイオエンジニアリング講演会講演論文集, 22 Jan. 2009, JapanesePropagation of Nonlinear Wave in Liquid Containing Encapsulated Microbubbles
Kanagawa Tetsuya, Yano Takeru, Watanabe Masao, Fujikawa Shigeo
Proceedings, ... meeting of Japan Society of Fluid Mechanics, 04 Sep. 2008, Japanese
One-dimensional nonlinear waves in a liquid containing a number of spherical microbubbles are theoretically studied on the basis of a two-fluid model equations. The set of averaged equations consists of conservation laws of mass and momentum in gas and liquid phases, and the equation of motion of bubble wall. The compressibility of liquid phase is taken into account in the conservation laws and the equation of bubble wall motion, and this leads to the wave attenuation due to bubble oscillations. By using the method of multiple scales, Korteweg-de Vries-Burgers equation can be derived. The properties of the equation are discussed and compared to previous results based on different models on bubbly liquids.337 Advection and Diffusion Transport Phenomena in Engineered Cartilage
NOBAYASHI Makoto, KITAJIMA Yousuke, WATANABE Shouhei, SAWAE Yoshinori, WATANABE Masao
年次大会講演論文集 : JSME annual meeting, 02 Aug. 2008, Japanese
Engineered cartilages are expected to be used for the treatment of cartilage defects. Cartilage tissue is avascular; hence transport phenomena are controlled by diffusion and also advection by so called "pumping mechanism" of tissue. The objective of present paper is to evaluate the contribution of both diffusion and advection in engineered tissue for the control of transport phenomena.703 Evaluation of Red Blood Cell Dynamics with High Speed Digital Video Capillaroscopy
NAKAMURA Yuuki, WATANABE Masao, IRIBE Masaki, MATSUBARA Mizuho
年次大会講演論文集 : JSME annual meeting, 02 Aug. 2008, Japanese
Nailfold video capillaroscopy (NVC) can observe the micro vascular structure non-invasively. We developed NVC by using high speed digital video camera to evaluate both micro vascular structure and red blood cell movement quantitatively The objects of this study are to evaluate the radius distribution of micro vascular by level-set method and also the red blood cell velocity by tracing plasma gap between blood cells.Evaluation of Red Blood Cell Dynamics with High Speed Digital Video Capillaroscopy
NAKAMURA YUKI, WATANABE MASAO, IRIBE MASAKI, MATSUBARA MIZUHO
日本機械学会年次大会講演論文集, 02 Aug. 2008, JapaneseAdvection and Diffusion Transport Phenomena in Engineered Cartilage
NOBAYASHI MAKOTO, KITAJIMA YOSUKE, WATANABE SHOHEI, SAWAE YOSHINORI, WATANABE MASAO
日本機械学会年次大会講演論文集, 02 Aug. 2008, Japanese単一上昇気泡の3次元後流の可視化
KOGA KIYONORI, SATO AYAKA, SHIROTA MINORI, SANADA TOSHIYUKI, WATANABE MASAO
日本混相流学会年会講演会講演論文集, Aug. 2008, Japanese超純水中を上昇する単一気泡の自由界面及び壁面との反発現象
UCHIDA YUSUKE, SATO AYAKA, SHIROTA MINORI, SANADA TOSHIYUKI, WATANABE MASAO
日本混相流学会年会講演会講演論文集, Aug. 2008, JapaneseB11 A Numerical Analysis of Liquid Film Formation on a Rotating Disk
MAEDA Daisuke, IWASAKI Tatsuya, WATANABE Masao, SANADA Toshiyuki
日本機械学会九州支部講演論文集, 19 Mar. 2008, Japanese125 Numerical Study of Blood Flow in the Hepatic Portion of the Inferior Vena Cava on Budd-Chiari Syndrome
MATSUBARA Mizuho, WATANABE Masao, WATANABE Satoshi, KONISHI Kozo, HASHIZUME Makoto
バイオエンジニアリング講演会講演論文集, 24 Jan. 2008, Japanese229 Diffusion transport phenomena in engineered cartilage
WATANABE Shohei, KITAJIMA Yosuke, NOBAYASHI Makoto, WATANABE Masao, MURAKAMI Teruo, SAWAE Yoshinori
バイオエンジニアリング講演会講演論文集, 24 Jan. 2008, JapaneseImage-based CFD of Blood Flow in the Hepatic Portion of the Inferior Vena Cava on Budd-Chiari Syndrome
MATSUBARA MIZUHO, WATANABE MASAO, WATANABE SATOSHI, KONISHI KOZO, YAMAGUCHI SHOHEI, HASHIZUME MAKOTO
日本機械学会年次大会講演論文集, 07 Sep. 2007, JapaneseHigh Speed Video Capillaroscopy and Capillary Vessel Blood Flow
IRIBE MASAKI, KURODA HIROAKI, WATABE MASAO, MATSUBARA MIZUHO, SANADA TOSHIYUKI
日本機械学会年次大会講演論文集, 07 Sep. 2007, JapaneseVisualization of Single Rising Bubble Wake
TAKETOMI YUTA, SATO AYAKA, SHIROTA MINORI, SANADA TOSHIYUKI, WATABE MASAO
日本機械学会年次大会講演論文集, 07 Sep. 2007, Japanese蒸気と水の混合噴流によるレジスト剥離
SANADA TOSHIYUKI, SAITO TAKAYUKI, SHIROTA TSUTOMU, WATABE MASAO, MORITA YOSHINAO, YAMASE MASAO
応用物理学会学術講演会講演予稿集, 04 Sep. 2007, Japanese水蒸気と水の混合噴流によるレジスト剥離・洗浄装置の開発
SANADA TOSHIYUKI, SHIROTA MINORI, WATANABE MASAO, YAMASE MASAO
日本学術会議混相流シンポジウム講演資料集, Jun. 2007, Japanese単一気泡の形状と定常抗力
SATO AYAKA, SHIROTA MINORI, SANADA TOSHIYUKI, WATABE MASAO
日本混相流学会年会講演会講演論文集, Jun. 2007, Japanese超純水中における単一気泡と自由界面との反発現象
UCHIDA YUSUKE, SATO AYAKA, SHIROTA MINORI, SANADA TOSHIYUKI, WATABE MASAO
日本混相流学会年会講演会講演論文集, Jun. 2007, Japanese気泡後部定在渦の可視化
SANADA TOSHIYUKI, SHIROTA TAKA, ONO YUKI, WATABE MASAO
化学工学会年会研究発表講演要旨集, 19 Feb. 2007, Japanese超純水中の気泡挙動
SANADA TOSHIYUKI, SHIROTA TAKA, SUGIHARA KEIJI, WATABE MASAO
化学工学会年会研究発表講演要旨集, 19 Feb. 2007, Japanese高速度ビデオcapillaroscopyとその画像解析
KURODA HIROAKI, MATSUBARA MIZUHO, IRIBE MASAKI, SANADA TOSHIYUKI, WATANABE MASAO
バイオエンジニアリング講演会講演論文集, 06 Jan. 2007, Japaneseバッドキアリ症候群機序解明に向けた血管形状セグメンテーションとモデル構築
MATSUBARA MIZUHO, HOTANABE MASAO, WATANABE SATOSHI, KONISHI KOZO, YAMAGUCHI SHOHEI, HASHIZUME MAKOTO
バイオエンジニアリング講演会講演論文集, 06 Jan. 2007, Japanese再生軟骨における組織形成と輸送現象
KITAJIMA YOSUKE, SUGINO SHOICHI, WATANABE MASAO, SAWAE YOSHINORI, SANADA TOSHIYUKI, MURAKAMI TERUO
バイオエンジニアリング講演会講演論文集, 06 Jan. 2007, JapaneseBubble Wake Visualization by using Photochromic Dye
SANADA TOSHIYUKI, SHIROTA MINORI, ONO TOMOKI, WATANABE MASAO
可視化情報学会論文集(Web), 2007, JapaneseMacro-scale transport phenomena in articular cartilage
SUGINO SHOICHI, KITAJIMA YOSUKE, WATANABE MASAO, SAWAE YOSHINORI, SANADA TOSHIYUKI, MURAKAMI TERUO
日本機械学会年次大会講演論文集, 15 Sep. 2006, JapaneseSite calibration by with the aid of CFD
FUJINO MASATOSHI, SHIROTA MINORI, SANADA TOSHIYUKI, MATSUSHITA DAISUKE, WATANABE MASAO, MATSUMIYA HIKARU
日本機械学会年次大会講演論文集, 15 Sep. 2006, JapaneseFormation of single bubbles controlled with fluctuating gas pressure
SANADA TOYUSHIKI, SHIROTA MINORU, ARATA YASUHIRO, WATANABE MASAO
日本機械学会年次大会講演論文集, 15 Sep. 2006, JapaneseBouncing and Coalescence of a pair of Bubbles in a Quiescent Liquid
SUGIHARA KEIJI, ONO TOMOKI, SHIROTA MINORI, SANADA TOSHIYUKI, WATANABE MASAO
日本機械学会年次大会講演論文集, 15 Sep. 2006, Japanese気体圧力変動を利用した単一微細気泡発生法
SANADA TOSHIYUKI, KIDA NO, WATANABE MASAO
化学工学会秋季大会研究発表講演要旨集(CD-ROM), 16 Aug. 2006, Japanese静止液体中を上昇する2気泡の合体および反発
SANADA TOSHIYUKI, WATANABE MASAO
化学工学会秋季大会研究発表講演要旨集(CD-ROM), 16 Aug. 2006, Japanese高Re数における水平に並んで上昇する2気泡の挙動
SATO AYAKA, SATO SHINSUKE, SHIROTA MINORI, SANADA TOSHIYUKI, WATANABE MASAO
日本混相流学会年会講演会講演論文集, Aug. 2006, Japaneseフォトクロミック染料による気泡後流渦の可視化
ONO TOMOKI, SHIROTA MINORI, SATO SHINSUKE, SANADA TOSHIYUKI, WATANABE MASAO
日本混相流学会年会講演会講演論文集, Aug. 2006, Japanese気体圧力変動を利用した単一微細気泡発生メカニズム
SHIROTA MINORI, SANADA TOSHIYUKI, ARATA YASUHIRO, WATANABE MASAO, KAMEDA MASAHARU
日本混相流学会年会講演会講演論文集, Aug. 2006, JapaneseCFDを援用した複雑地形における風車流入風計測法
SHIROTA MINORI, FUJINO MASATOSHI, SANADA TOSHIYUKI, WATANABE MASAO, MATSUMIYA HIKARU
日本機械学会九州支部講演論文集, Mar. 2006, Japaneseフォトクロミック染料による気泡後流の可視化
ONO TOMOKI, SATO SHINSUKE, SHIROTA MINORO, SANADA TOSHIYUKI, WATANABE MASAO
日本機械学会九州支部講演論文集, Mar. 2006, Japanese再生関節軟骨組織形成と輸送現象の可視化
SUGINO SHOICHI, HAARI KENTA, WATANABE MASAO, SAWAE YOSHINORI, SANADA TOSHIYUKI, MURAKAMI TERUO
バイオエンジニアリング講演会講演論文集, 12 Jan. 2006, Japaneseバッドキアリ症候群における血流シミュレーション
MATSUBARA MIZUHO, WATANABE MASAO, WATANABE SATOSHI, HASHIZUME MAKOTO, KONISHI KOZO
バイオエンジニアリング講演会講演論文集, 12 Jan. 2006, JapaneseNon-axisymmetric Bubble motion and Wake Structure
ONO TOMOKI, SANADA TOSHIYUKI, SUGIHARA KEIJI, SHIROTA MINORI, WATANABE MASAO
日本機械学会流体工学部門講演会講演論文集(CD-ROM), 2006, JapaneseShape and terminal velocity of a single bubble in superpurified water
SUGIHARA KEIJI, ONO TOMOKI, SATO AYAKA, SHIROTA MINORI, SANADA TOSHIYUKI, WATANABE MASAO
日本機械学会流体工学部門講演会講演論文集(CD-ROM), 2006, JapaneseHigh Speed Video Capillaroscopic Analysis of Human Capillary Vessel Blood Flow
WATANABE MASAO, SANADA TOSHIYUKI, SAWAE YOSHINORI, MATSUBARA MIZUHO, KURODA HIROAKI, FURUE MASUTAKA
日本機械学会流体工学部門講演会講演論文集(CD-ROM), 2006, Japanese高島町における数値サイトキャリブレーションの試み
FUJINO MASATOSHI, SANADA TOSHIYUKI, MATSUSHITA DAISUKE, UCHIDA TAKANORI, WATANABE MASAO, MATSUMIYA HIKARU
風力エネルギー利用シンポジウム, Nov. 2005, Japanese水平に並んで上昇する2気泡の反発現象
SANADA TOSHIYUKI, SUGIHARA KEIJI, WATABE MASAO, FUKANO TOORU
日本混相流学会年会講演会講演論文集, Aug. 2005, Japanese培養軟骨細胞による組織構造形成と力学的機能発現
SAWAE YOSHINORI, ISHIYAMA SHO, HANAKI AKIHIRO, WATANABE MASAO, MURAKAMI TERUO
日本ME学会大会論文集, 25 Apr. 2005, Japanese水平に並んで上昇する2気泡の合体および反発
SUGIHARA KEIJI, SATO SHINSUKE, SANADA TOSHIYUKI, WATANABE MASAO, FUKANO TOORU
日本機械学会九州支部講演論文集, Mar. 2005, Japanese格子ボルツマン法の境界条件に関する検討
UEZONO DAISUKE, SANADA TOSHIYUKI, WATANABE MASAO, MATSUKUMA YOSUKE
日本機械学会九州支部講演論文集, Mar. 2005, Japaneseヒト毛細血管のin vivo血流・形状観察
SANADA TOSHIYUKI, WATANABE MASAO, SAWAE YOSHINORI, FURUE MASUTAKA
バイオエンジニアリング講演会講演論文集, 21 Jan. 2005, Japanese再生関節軟骨内輸送現象の可視化(細胞活動の影響)
WATANABE MASAO, SAWAE YOSHINORI, SANADA TOSHIYUKI, HAARI KENTA, MURAKAMI TERUO
バイオエンジニアリング講演会講演論文集, 21 Jan. 2005, JapaneseViscosity Effects on Bouncing and Coalescence of a Pair of Bubbles
SANADA TOSHIYUKI, SATO AYAKA, WATANABE MASAO, FUKANO TOORU
日本機械学会年次大会講演論文集, 04 Sep. 2004, Japanese単一ノズルから連続して発生させた2気泡の挙動に関する研究
SANADA TOSHIYUKI, WATANABE MASAO, ISHIDA DAIJIRO, FUKANO TOORU
日本混相流学会年会講演会講演論文集, Aug. 2004, JapaneseIn Vivo Analysis of Human Capillary Vessel Blood Flow and Vessel Shape
WATANABE MASAO, SANADA TOSHIYUKI, SAWAE YOSHINORI, FURUE MASUTAKA
日本機械学会流体工学部門講演会講演論文集(CD-ROM), 2004, Japanese水平に並んで上昇する2気泡の挙動に関する研究
SANADA TOSHIYUKI, SATO SHINSUKE, WATANABE MASAO, FUKANO TOORU
日本機械学会流体工学部門講演会講演論文集(CD-ROM), 2004, JapaneseEffects of Chondrocyte Activity on Macro-Scale Transport Phenomena in Regenerated Articular Cartilage Tissue
WATANABE MASAO, SAWAE YOSHINORI, HAARI KENTA, SANADA TOSHIYUKI, MIZUNO CHUICHI, MURAKAMI TERUO
日本機械学会流体工学部門講演会講演論文集(CD-ROM), 2004, JapaneseStudy on Adsorption on Gas-Liquid Interface by Totao Internal Relection Fluorescence Microscopy
WATANABE MASAO, SAWAE YOSHINORI, SANADA TOSHIYUKI, YOTSUMOTO KIYOSHI, MURAKAMI TERUO
日本機械学会流体工学部門講演会講演論文集(CD-ROM), 2004, Japanese横に並んだ上昇2気泡の挙動に関する研究
NODA HITOMI, SANADA TOSHIYUKI, WATANABE MASAO, FUKANO TOORU
日本機械学会九州支部地方講演会講演論文集, 01 Nov. 2003, JapaneseBubble Behaviors and Liquid Flow Structures in Single Bubble Chain(Liquid Jet Development by Single Bubble)
SANADA TOSHIYUKI, WATANABE MASAO, FUKANO TOORU
日本機械学会流体工学部門講演会講演論文集, 19 Sep. 2003, Japanese単一気泡列中の気泡挙動および周囲液体流れ場構造 (気泡列による液ジェットの生成)
SANADA TOSHIYUKI, WATANABE MASAO, FUKANO TOORU
日本機械学会流体工学部門講演会講演論文集, 18 Sep. 2003, Japanese自由界面での単一気泡の合体および反発に関する研究
SANADA TOSHIYUKI, WATANABE MASAO, FUKANO TOORU
日本混相流学会年会講演会講演論文集, Jul. 2003, Japaneseレベルセット法を用いたCFDによるMRアンギオグラフィーの修正
WATANABE MASAO, KIKINIS R, WESTIN C-F
数値流体力学シンポジウム講演論文集, 16 Dec. 2002, Japanese自由界面近傍における単一上昇気泡の合体・反発に及ぼす粘性の影響
SANADA TOSHIYUKI, WATANABE MASAO, YUDA TOMOHIRO, FUKANO TOORU
数値流体力学シンポジウム講演論文集, 16 Dec. 2002, Japanese単一ノズルから発生する気泡列による周囲流体の挙動に関する研究
SANADA TOSHIYUKI, WATANABE MASAO, FUKANO TOORU
日本混相流学会年会講演会講演論文集, Jul. 2002, Japanese単独のノズルから発生する気泡列の挙動に及ぼす発生頻度および気泡径の影響
SANADA TOSHIYUKI, WATANABE MASAO, FUKANO TOORU
日本機械学会九州支部地方講演会講演論文集, 12 Oct. 2001, Japanese単独のノズルから発生する気泡列の挙動に及ぼす発生頻度の影響
SANADA TOSHIYUKI, WATANABE MASAO, FUKANO TOORU, KARIYAZAKI AKIRA
日本混相流学会年会講演会講演論文集, Jul. 2001, Japanese二つの気液界面が互いに近づく時の界面間の流体の挙動
ONIZUKA RYUJI, WATANABE MASAO, FUKANO TOORU
日本混相流学会年会講演会講演論文集, Jul. 2000, JapaneseNumerical Analysis on Motion of a Pair of Rising Bubbles by Using Finite Element Method with Time Dependent Non-Structured Deforming Grid.
WATANABE MASAO, SHRESTHA R, FUKANO TOORU
日本機械学会計算力学講演会講演論文集, Nov. 1998, JapaneseNumerical Analysis on the In-line Motion of a Pair of Rising Deforming Bubbles.
WATANABE MASAO, SHRESTHA R, FUKANO TOORU
日本機械学会流体工学部門講演会講演論文集, Aug. 1998, Japanese数値シミュレーションを用いた気流を伴う水平矩形管内薄膜流に関する研究
INATOMI TAKANARI, FUKANO TOORU, WATANABE MASAO
混相流シンポジウム講演論文集, Jul. 1998, Japanese時間依存非構造変形格子を用いた気泡運動の有限要素法による数値計算
WATANABE MASAO, SHRESTHA R, FUKANO TOORU
混相流シンポジウム講演論文集, Jul. 1998, JapaneseWeakly Nonlinear Analysis on Translational Motions of Two Bubbles in Periodically Driven Pressure Field.
WATANABE MASAO
日本機械学会計算力学講演会講演論文集, Jul. 1997, JapaneseA novel way of computing heat transfer in bubble dynamics.
WATANABE MASAO, MATSUMOTO YOICHIRO
日本機械学会計算力学講演会講演論文集, Jul. 1997, JapaneseAffiliated academic society
Research Themes
- Evaporation coefficient of nanoparticle suspension
Grants-in-Aid for Scientific Research
01 Apr. 2024 - 31 Mar. 2028
小林 一道, 藤井 宏之, 渡部 正夫
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 24K00797 - 蒸気中の液滴固体面衝突における凝縮効果によるsplash発生抑制機序の解明
科学研究費助成事業
01 Apr. 2024 - 31 Mar. 2026
渡部 正夫, 小林 一道, 藤井 宏之, 真田 俊之
日本学術振興会, 基盤研究(B), 北海道大学, 23K26027 - Elucidation of non-equilibrium phase change at gas-liquid interface mechanism for mixture gas and its application to molecular multi-phase fluid dynamics
Grants-in-Aid for Scientific Research
01 Apr. 2020 - 31 Mar. 2023
小林 一道, 藤井 宏之, 渡部 正夫
本提案研究は，混合気体に接した気液界面における気体論境界条件を構築し，様々な分野に本研究成果を展開することである．2021年度は主に以下の３つの研究を行った．
１．分子計算（分子運動論および分子動力学シミュレーション）を用いて，非平衡気液界面における気体論境界条件の構築を行った．その結果，気体論境界条件に含まれる二つの未知パラメータ（蒸発係数および凝縮係数）を決定した．本結果より，非平衡気液界面における蒸発係数と凝縮係数の値は，平衡状態および非平衡状態においてほぼ変わらないことが明らかとなった．これにより，初期液体温度などの条件にもよるが，平衡状態の蒸発係数および凝縮係数を求めておけば気体論境界条件を構築できることが示唆された．
２．分子動力学解析を用いて，固体壁と液体に挟まれた気体のクエット流れについて解析を行った．この研究より，気液界面における気体論境界条件の位置を検証した．本研究より，１の研究で指定していた気体論境界条件の位置は妥当であることが示唆された．また，高クヌーセン数流れになるほど，気液界面の境界条件が平衡状態の関数形から異なることが示唆された．これについてはさらなる検討が必要である．
３．分子動力学解析を用いて，混合液体（エタノール・イソオクタン）の蒸発について検証した．分子動力学計算を用いてエタノール・イソオクタンの気液平衡系を作り出し，１の研究で提案した方法によって，液体から蒸発する分子の成分について調べた．その結果，エタノールの濃度が低い混合液体においても，蒸発するエタノール分子の割合は高くなることが示された．今後はこの知見を用いて実験結果を整理する予定である．
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 20K04277 - Influence of the interference effects on radiative transfer in dense colloidal suspensions
Grants-in-Aid for Scientific Research
01 Apr. 2020 - 31 Mar. 2023
藤井 宏之, 西村 吾朗, 渡部 正夫, 小林 一道
本研究の目的は、「生体を模擬した高密度なコロイド溶液に対して、輻射（ふくしゃ）の干渉効果を組み込んだ輻射輸送モデル(輸送モデル)を新たに構築した上で、干渉効果が及ぼす光伝播への影響を明らかにすること」である。生体光イメージングや光治療において、生体内の光伝播を定量的に把握することが必要であり、光を輻射と捉えた輸送モデルが活用されている。しかし、従来の輸送モデルには、生体のような高密度な散乱媒体において重要となる干渉効果が考慮されていない。本研究では電磁波の散乱理論より干渉効果を考慮した散乱特性を計算し、輸送モデルに組み込んだ上で光強度の時間分解波形を数値計算する。また、短パルスレーザー光源による光強度計測も実施する。干渉効果が光伝播へ影響を及ぼす時空間スケールについて、散乱係数などで表される無次元数を用いて解析し、理論、数値計算、実験より体系的に明らかにする。この目的を達成するため、本年度は以下の３項目について研究を実施した。
１．光散乱特性を簡潔に記述するモデル式を開発した。モデル式により、単一散乱の寄与と干渉効果の寄与を分離して評価することに初めて成功した。
２．分担研究者の西村吾朗助教の波長可変の光計測システムを利用して、コロイド溶液（脂質エマルジョン）において、濃度20%まで21条件、720 nmから860 nmまでの6条件で光計測を実施した。光計測データを逆解析することで算出した光学特性値をモデル式より解析し、干渉効果の波長依存性を明らかにした。
３．分子動力学シミュレーションにより構造特性を計算し、干渉散乱理論に組み込んで散乱特性を計算した。粒子間の引力相互作用が散乱特性に強く影響を及ぼすことを明らかにした。
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 20H02076 - 高Oh液滴の固体面衝突直後に発生するsplashの相似則構築とメカニズム解明
科学研究費助成事業
01 Apr. 2020 - 31 Mar. 2023
渡部 正夫, 小林 一道, 藤井 宏之, 真田 俊之
本研究の目的は，「高Oh液滴の固体面衝突直後に発生するcorona splashとprompt splashの発生条件を明らかにし，二つのsplashの発生メカニズムを説明する理論モデルを構築すること」である．この目的を達成するために，本年度は以下の２項目について研究を行った．
１．固体表面に滴衝する高Oh液滴の観察：自由落下するシリコンオイルを用いて衝突実験を行い，高Oh液滴のsplash発生条件を探索した．高粘度液滴衝突ではあるOhを閾値としてsplashとreceding break-upの２種類の不安定性が観察されること, 閾値Oh数以上ではreceding break-upのみが観察されさらにOh数を大きくすると不安定性が観察されないこと，receding break-upはある衝突速度以上では観察されないことを明らかにした．
２．粗い表面に衝突する液滴の観察：低圧力環境下の高速液滴衝突 (50m/s程度) 実現を行い，固体表面粗さの効果を検討するために，減圧チャンバ内での粗い固体表面への高速液滴衝突を観察した．平滑表面および粗い固体表面においてsplashの発生閾値を検討した．低Oh液滴衝突においては，これまで観察されていたcorona splashとprompt splashに加えて衝突直後極短時間にのみ観察されるsplashが存在することが発見され，これまでに提案されたsplash発生閾値モデルは，粗い表面には適用できないことを明らかにした．
３．高速度カラー光干渉計による気液界面計測システムによる観察：固体表面に衝突する液滴の固体面衝突直前に，固体表面と液滴との間に形成される薄空気膜はsplash発生に大きな影響を与える．この薄空気膜厚さの空間分布の時間変化が，固体表面電位と液体の誘電率によって大きく変化することを明らかにした．
日本学術振興会, 基盤研究(B), 北海道大学, 20H02061 - 表面プラズモン共鳴観察によるアクティブマターのメカニズムの解明
科学研究費補助金(挑戦的研究(萌芽))
Apr. 2018 - Mar. 2020
渡部 正夫
日本学術振興会, Principal investigator, Competitive research funding - 高速射出液膜流れの固気液三相接触線近傍流れ場の不安定現象に及ぼす周囲気体効果
科学研究費補助金(基盤研究(B))
Apr. 2017 - Mar. 2020
渡部 正夫
日本学術振興会, Principal investigator, Competitive research funding - Determination of kinetic boundary conditions for gas-vapor binary mixture and its application
Grants-in-Aid for Scientific Research
01 Apr. 2016 - 31 Mar. 2019
Kobayashi Kazumichi, KON Misaki
The aim of this study is to determine the kinetic boundary conditions for vapor (condensable gas) - gas (non-condensable gas) binary mixture. We also apply the boundary conditions for multi phase flow, especially for the analysis of bubble collapse problem.
In the present study period, molecular dynamics method was used to construct the kinetic boundary conditions for vapor-gas mixture at equilibrium. We also solved the problem of the bubble collapse using the boundary conditions obtained from the molecular dynamics simulation. As a result, it was suggested that a thin layer composed of non-condensable gas is formed in the vicinity of the gas-liquid interface when the bubble collapses, and it was indicated that the condensation coefficient becomes extremely low due to the influence of this layer. It was also revealed that the internal temperature field when bubble collapses was affected by a small amount of non-condensable gas contained in the bubble.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 16K06064 - Condensation effect on high-speed liquid-film flow instability at a liquid-droplet impact on a solid surface in a vaporous environment
Grants-in-Aid for Scientific Research
2014 - 2016
WATANABE MASAO
Droplet impacts on solid surface are key elements in technical applications, such as rapid spray cooling, ink-jet printing and semiconductor cleaning. Although the broad varieties of parameters that control splash formation after the droplet impact, are proposed, they are not thoroughly explored; hence, dynamics of the droplet after the impact are yet fully understood. After droplet impacts on solid surface, characteristic film flow is developed; then splash may be generated. In this study, we examine the effects of the temperature of surrounding gas, which is either condensable or non-condensable, on ethanol droplet impact. We found that splash can be suppressed with the increase of the surrounding gas temperature. We measured the splash threshold pressure for a splash to appear as a function of the temperature. The results show that the splash threshold pressure is a monotonically increasing function of the surrounding gas temperature.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Principal investigator, Competitive research funding, 26289031 - Investigation of mass transport mechanism in fuel cel by a hierarchical multi-physics simulation concept
Grants-in-Aid for Scientific Research
01 Apr. 2011 - 31 Mar. 2015
OSHIMA Nobuyuki, WATANABE Masao, KURIHARA Eru, YAGUCHI Hisao
For multi-scale flow phenomena concerning to fuel cell performance, a hierarchical multi-physics simulation concept is investigated to couple between molecular dynamics, non- equilibrium thermodynamics and unsteady flow simulation. Validations and improvements of mathematical models and numerical methods are performed on the following problems; 1) unsteady coupling simulation of cell / stack level performance of fuel cell design, 2) validations of lattice Boltzmann method for gas-liquid interface simulation and water transport models in catalyst layer, and 3) gas-liquid mixed gas simulation with 6-site potential model for water molecule.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 23360079 - Study of unsteady heat and mass transfer at the strong non-equilibrium interface ugin mean-field kinetic theory
Grants-in-Aid for Scientific Research
2014 - 2015
Watanabe Masao, KOBAYASHI KAZUMICHI, YAGUCHI HISAO, HIROYUKI FUJII
The aim of this study is to examine a kinetic boundary condition that depends on liquid temperature for the Boltzmann equation in a vapor-liquid two-phase system during unsteady net evaporation/condensation in a strong non-equilibrium status.We carried out numerical simulations of the unsteady heat and mass transfer in the vicinity of interface at the strong non-equilibrium status by using EV-DSMC method; then, we constructed the kinetic boundary condition that can prescribe the heat and mass transfer in the vicinity of the interface in the frame work of the macroscopic fluid mechanics. We proposed a novel model of the bubble dynamics with phase change taken into consideration. We also investigated the bubble dynamics with phase change.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, Principal investigator, Competitive research funding, 26630043 - Development of nonlinear nonequilibrium fluid mechanics through comprehensive integration of molecular dynamics of vapor-liquid interface and molecular gas dynamics
Grants-in-Aid for Scientific Research
01 Apr. 2011 - 31 Mar. 2014
YANO Takeru, AOKI Kazuo, TAKATA Shigeru, WATANABE Masao
The ultimate goal of this research is to break a new ground of nonlinear nonequilibrium fluid mechanics by a comprehensive integration of molecular dynamics at the vapor-liquid interface and molecular gas dynamics based on the theory of Boltzmann equation. To this end, we have performed several specific analyses: 1. General formulation of nonequilibrium unsteady vapor motions accompanied with evaporation or condensation at the interface; 2. Establishment of reciprocity among elemental relaxation and driven-flow problems for a rarefied gas; 3. Careful investigation of applicability of macroscopic fluid mechanics to some nano-scale flows.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Osaka University, 23246034 - Study of elementary process of novel cleaning method by investigation of surrounding condensable vapor effect on single droplet drag reduction
Grants-in-Aid for Scientific Research(基盤研究(B))
2010 - 2012
Masao WATANABE, 真田 俊之, 小林 一道, 矢口 久雄
In the cleaning processes of manufacturing semiconductor deVices, two-fluidspray cleaning technique is widely used. In this study, we fbcus our attention to the elementary process ofthis cleaning technique, i.e. a single droplet impact on a solid surface. We experimentally observe impact ofsingle droplet on a rigid solid surface. Especially we focus on the effects of surfaces tension, surfaceroughness and surrounding pressure. Decrease of the surrounding gas pressure makes droplets alwayscreate lamella even in the cases with low surface tension and rough surfaces
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 北海道大学, Principal investigator, Competitive research funding, 22360073 - Study on Transport phenomena at supercritical mixure interface by moelcular velocity distribution function and mean field kinetic theory
Grants-in-Aid for Scientific Research(挑戦的萌芽研究)
2011 - 2011
Masato WATANABE, 小林 一道, 矢口 久雄
Transport phenomena on vapor-liquid mixture interface is studied for the accurate prediction of fuel mixture concentration,which leads to the development of highly reliable liquid fuel rocket engine. Numerical simulations f()r vapor liquid twophase systems were perf()mled by using the mean field kinetic theory.The kinetic boundaiy condition(KBC)at theinterface was investigated. We also execute molecular dynamics simulations oftwo-component vapor-liquid equilibrium systemsofbinary system to investigate heat/mass transport phenomena on mixtUre interface.
Ministry of Education, Culture, Sports, Science and Technology, 挑戦的萌芽研究, 北海道大学, Principal investigator, Competitive research funding, 23656122 - Multiscale study on molecular transport process near nonequilibrium vapor-liquid interfaces governed by three physical laws
Grants-in-Aid for Scientific Research
2009 - 2011
FUJIKAWA Shigeo, YANO Takeru, WATANABE Masao, KOBAYASHI Kazumichi, YAGUCHI Hisao, PENG Guoyi
This research project has been performed to clarify molecular transport process at vapor-liquid interfaces in nonequilibrium states by multiscale methods. The results can be summarized as follows :(1) Determination of evaporation and condensation coefficients by shock tube and molecular gas dynamics,(2) Determination of evaporation coefficient by sound wave,(3) Formulation of kinetic boundary condition at curved vapor-liquid interface, and (4) Asymptotic analysis of unsteady kinetic boundary condition at arbitrarily-shaped vapor-liquid interface by molecular gas dynamics.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, Coinvestigator not use grants, Competitive research funding, 21246031 - 革新的洗浄方法原理解明のための水蒸気・水混相噴流衝突速度における凝縮効果の解析
科学研究費補助金(挑戦的萌芽研究)
2009 - 2010
渡部 正夫, 小林 一道
本研究では,研究代表者らが提案した水蒸気と水を混合しノズルから噴射する革新的混相噴流洗浄方法の基本原理を解明することを目的としている.具体的には,水蒸気中の水液滴が固体表面上の水液膜に衝突することにより発生する衝突圧力に着目する.この衝突圧力は,液滴衝突速度に大きく左右されるため,衝突速度を正確に見積もる必要があり,液滴界面および固体表面での凝縮効果を高精度で解析することが必要である.従って,分子気体力学を用いることが必要不可欠である.本年度は,昨年度構築した気体分子力学と連続体数値流体力学を融合させた数値解析スキーム開発のための基礎モデルの評価を行った.球対称一次元座標系を用いて,Gaussian-BGK-Boltzmann方程式に従う多原子分子気体が,球形液滴に凝縮する過程の数値シミュレーションを行った.液滴周囲の圧力分布を観察することにより液滴に働く抗力を算出した.気液界面の境界条件を支配する蒸発・凝縮係数に液滴抗力は大きく依存し,蒸発・凝縮が発生することにより液滴抗力が低下することを確認した.さらに,より現実的な系を取り扱うために,気体中に分子の占める体積が無視できないような高密度の気体に対して有効である,Enskog-Vlasov方程式を用いることを試みた.Boltzmann方程式の直接解法であるDSMC法を拡張したParticle Scheme法を用いて,単純な系...
文部科学省, 挑戦的萌芽研究, 北海道大学, Principal investigator, Competitive research funding, 21656048 - Development of functional surface structure and lubrication ability in articular cartilage tissue under tribologycal stimulation
Grants-in-Aid for Scientific Research(基盤研究(B))
2008 - 2010
Yoshinori SAWAE, Masao WATANABE, Nobuo SAKAI
Process and mechanism in the functional adaptation of superficial zone tissue structure of articular cartilage to tribological stimulations was explored. A well established three dimensional culture system for isolated chondrocytes, chondrocyte-agarose construct, was employed as a regenerated cartilage model and mechanical stimulations, such as cyclic compression, shear and surface friction, were applied to the model to examine their effects on cell metabolisms and the subsequent development of functional tissue structure for joint lubrication.
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 九州大学, Coinvestigator not use grants, Competitive research funding, 20360078 - Modeling of Transport Phenomena and Physical Stimulus Response in Engineered Cartilage Tissue Development
Grants-in-Aid for Scientific Research(基盤研究(B))
2007 - 2009
Masao WATANABE, 坂井 伸朗, 真田 俊之, 澤江 義則, 坂井 伸朗, 真田 俊之
We visualized transport phenomena in developing engineered cartilage tissues. The promotion of mass transfer due to the existence of cells inside test pieces are observed. The cell metabolism increased the diffusion transport. Generated polymers that consist extra-cellular matrices, such as negatively charged keratan sulfate, restrict diffusion transport. We also clarified the effects of advection transport due to the compression on diffusion transport.
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 九州大学->北海道大学->九州大学->北海道大学, Principal investigator, Competitive research funding, 19360087 - Effects of tribological stimulation on chondrocyte metabolism and development of functional cartilage tissue structure for joint lubrication
Grants-in-Aid for Scientific Research(基盤研究(C))
2006 - 2007
Yoshinori SAWAE, 渡部 正夫
Articular cartilage is one of the unique and interesting soft tissues since it covers articulating surfaces of diarthrodial joints and plays an important role as "bearing" to achieve smooth joint movements. However, the detailed mechanism which governs the establishing process of the sophisticated tribological functions on the cartilage surface has not been clarified yet The purpose of this research project has been to investigate the developing process of functional cartilage tissue structure for the joint lubrication by the metabolic response of chondrocytes to the mechanical loadings exp...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(C), 九州大学, Coinvestigator not use grants, Competitive research funding, 18560137 - Milli, Micro and Nano Fluidics in Air-Lift Operated Tank for Culture of Animal Cell
Grants-in-Aid for Scientific Research(基盤研究(B))
2005 - 2006
Masao WATANABE, 真田 俊之, 澤江 義則, 杉村 丈一
For the further improvement of bubble-driven airlift-operated tank for closed-system culture of animal cell, we studied both rising bubble behavior, and transport phenomena of cell and extra cellular matrix.It is highly required for the realization of the homogeneous bubbly flow that the most optimized bubble number density, i.e., bubble diameter and bubble mutual distance, should be determined. We observed the bubble motion in super purified water since the surfactant effects are essential for the bubble motion.It was found that the contact time of rising bubble with free surface was const...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 九州大学, Principal investigator, Competitive research funding, 17360082 - ヒト皮膚毛細管動静脈ループの血流動態と血管形状の非侵襲・高時空間解像度解析
科学研究費補助金(萌芽研究)
2005 - 2005
渡部 正夫, 真田 俊之, 澤江 義則, 古江 増隆
本研究の目的は,ヒト皮膚毛細管動静脈ループに注目し,血流動態と血管形状の非侵襲・高時空間解像度解析を行うシステムを開発することである.まず,ヒト爪郭皮膚毛細管動静脈ループを観測するために,計測システムを構築した.特に,被写体から対物レンズまでの距離を固定し,被写体のブレを抑えるために光学アタッチメントの開発を行い,実用に耐えうることを確認した.また,高速度カメラで被写体を撮影し,画像のブレを抑制するためにシャッタースピードを上げる必要があるために光源の高光度が要求されるが,光源は熱源となるために過度の光量は被写体の熱損傷を引き起こす.光源・レンズ・光学系の設計・開発を行い,照射面積を大幅に減じ効率の向上を図った結果,鮮明な画像取得と被写体の低侵襲観察の相反する要求を満足させることに成功した.さらに,フレキシブルアームスタンドによりカメラを固定することにより,光軸に空間自由度を与えることに成功し,ヒト皮膚毛細管動静脈ループに限定されない他の皮膚毛細血管,特に血管腫等の観察の臨床応用に適用可能であることを示した.得られた画像には,Matlabを用いて様々な画像処理を施すことにより画像強調を行い,生画像に比して格段の視認性を得られることを確認した.10μm程度の径を持つ細小動静脈管内を流れる赤血球,白血球および血漿の非定常挙動の観察に成功した.また,医療画像認識工学で用いられるレベ...
文部科学省, 萌芽研究, 九州大学, Principal investigator, Competitive research funding, 17656068 - Bio-Material Transport Pump Activated by Liquid Jet around Single Rising Bubble Chain
Grants-in-Aid for Scientific Research(基盤研究(B))
2003 - 2004
Masao WATANABE, 松下 大介, 古川 明徳
It was confirmed that a characteristic flow field existed in surroundings of the rising bubble chain which was row though it was generated from a single nozzle. The bubble chain was generated in the water pool with both the bubble diameter and bubble generation frequency accurately controlled, and the generation process of this characteristic flow field in the neighborhood of the bubble chain was observed. The lift force acting on bubbles in the bubble chain is larger than the one acting on a single bubble, due to the flow field formed by the leading bubbles. It is considered that the wake ...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 九州大学, Principal investigator, Competitive research funding, 15360096 - 数値流体力学とMR血流データとを用いた高精度血管セグメンテーション法の開発
科学研究費補助金(萌芽研究)
2003 - 2004
渡部 正夫
1.磁気共鳴位相コントラスト血管撮像法(MR-PCA)において,数値流体力学の手法を用いることにより,得られた血流流れ場を修正すると共に,より高精度の血管形状の認識・輪郭抽出を行うための手法を提唱し,高制度化をはかった。特に本手法は初期の血管セグメンテーションに精度が依存するために,より高精度化をはかるため,レベルセット法を用いた三次元医療イメージングの輪郭抽出において,閾値法に基づく手法を検討した.レベルセット法の中で適用例の多い再初期化法と測地的動的輪郭法とを組み合わせることにより,再初期法の堅牢性・収束性の良さと,測地的動的輪郭法の解曲面の平滑性とを併せ持つ手法を開発した.この手法のパラメータ強度を調査するために,MRデータのみならず,毛細血管データにも適用し複雑血管形状を抽出した.血管壁認識力の高い再初期化法と血管壁再構成力の高い測地的動的輪郭法との混合を単一のパラメータで制御することが可能であることを認識した.さらに,測地的動的輪郭法の特徴を生かすことにより,従来は画像幾何より求められていた血管の管径・曲率等の特徴値をレベルセット関数を用いて解析的に求める手法を提唱した.2.複雑な3次元血管内の血流をシュミレートするためには,単純な境界条件と並列化の容易さが要求される.そこで,血流流れソルバを従来の差分法から格子ボルツマン法へと改良するための検討を行った.特に境界条...
文部科学省, 萌芽研究, 九州大学, Principal investigator, Competitive research funding, 15656051 - RESEACH ON THE GENERATION MECHANISM OF BURNOUTNEAR THE FLOW OBSTRACTION IN BOILING TWO-PHASE FLOW WITHIN ANANNULAR CHANNEL
Grants-in-Aid for Scientific Research(基盤研究(B))
2002 - 2003
Tohru FUKANO, 渡部 正夫
In order to clarify the mechanism of burnout occurrence near the obstacle, which simulate spacers of BWR, flow phenomena was carefully observed' by using a high-speed video and time varying wall temperatures were measured at many axially different locations. The results are summarized as follows.1.In relation to the occurrence of burnout, we carefully observed two-phase flow phenomena. The generation of dry-out of liquid film, which acts as a trigger of generation of burnout, is caused by the dry-out of base film between two disturbance waves at the location upstream of the spacer. On the o...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 九州大学, Coinvestigator not use grants, Competitive research funding, 14350094 - 軟骨生体組織内マクロ輸送現象の流体力学モデルの構築
科学研究費補助金(萌芽研究)
2002 - 2002
渡部 正夫, 松下 大介
血管が存在しない軟骨組織を対象として,生体組織における組織レベルのマクロスケールなマクロな輸送現象輸送現象に関して研究を行った.軟骨組織内には血管細胞が欠如しているため,組織内の輸送現象は主に拡散・浸透によるものであると考えられる.本研究では分子量の異なる蛍光マーカーを培地に混入し,牛関節軟骨より切り出した軟骨微小組織切片を一定期間培養し,蛍光マーカーが拡散した軟骨組織の,連続凍結切片の蛍光顕微鏡像に画像処理を施し,蛍光マーカー空間分布を定量化することにより,細胞組織内への輸送現象を観察した.その結果,以下の知見を得た.1.軟骨組織内の物質輸送は,組織の幾何学的構造,生物理学的特徴の異方性により大きく影響を受ける.軟骨組織の加重方向に輸送されるマーカー量は,加重方向の直交方向に輸送されるマーカー量に卓越している.特に軟骨組織表層部よりのマーカーの浸入が顕著であることが観察された.2.分子量の異なるマーカーを用いることにより,拡散速度および拡散量に大きな違いが観察された.特に,分子量500kD程度のマーカーの場合には,組織内部への侵入がほとんど観察されなかった.3.分子量の等しいFITC-dextranとRITC-dextranをマーカーとして用い,12時間培養を行った結果,拡散様式に大きな違いが観察された.FITCは負に荷電され,RITCは中性であることが,電気泳動を用いて確...
文部科学省, 萌芽研究, 九州大学, Principal investigator, Competitive research funding, 14655073 - Development of the Cooling System for MPU of Mobile Personal Computer
Grants-in-Aid for Scientific Research(基盤研究(B))
2001 - 2002
Tohru FUKANO, 宮原 雅晴, 渡部 正夫
Mobile personal computers are developing quickly in miniaturization with high performance. With this direction heat generation from the MPU will become higher and higher. And in near future it is supposed to become twice and triple times of the present value. And therefore the high heat generation must be taken into consideration in thermal design of such mobile computers. Recent investigation shows that the heat can be distributed by use of a small size heat pipes. The accumulated heat within the case of the computer, however, must be eventually transferred out of the case by use of some k...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 九州大学, Coinvestigator not use grants, Competitive research funding, 13555047 - 気泡の体積変化を利用したマイクロポンプの作動原理に関する熱流体力学的研究
科学研究費補助金(奨励研究(A))
2000 - 2001
渡部 正夫
気泡運動を利用したマイクロポンプの作動原理を理解するためには,気泡運動により誘起される周囲流体挙動を解析することが必要である.特に,今年度は気泡運動が比較的単純な場合についてのみ検討することにより,基礎的データを取得することを目的とした.そのため,モノポールとダイポールがそれぞれ支配的な流れ場について考察を行なった.気泡運動として径方向運動(モノポール)が支配的な流れ場に関しては,より複雑な流れ場を形成し得る気泡群の挙動により誘起される周囲流体,特に形成される圧力場に関して考察した.多数の気泡が液体中のある領域内に高い密度で存在する気泡群の場の圧力の変動に対する挙動を,多重極展開法・摂動展開法に基づく数学モデルを構築し数値計算を行なった.気泡群の線形圧力応答を解析することにより,少数の気泡が存在すれば,連続体モデルにより予測される音響特性を生じることが確認された.また,離散モデルを用いて,気泡群周囲圧力を急激に上昇させることにより気泡群内の気泡を収縮させる,キャビテーション気泡群崩壊の単純モデルを提案した.並進運動(ダイポール)が支配的な流れ場を解析するためには,最も単純な場合であると考えられる同一直線上を上昇する気泡による流れ場解析を有限要素法による数値シミュレーションにより行なった.DSD/ST(deforming-spatial-domain/space-time)有限...
文部科学省, 奨励研究(A), 九州大学, Principal investigator, Competitive research funding, 12750143 - Mechanisms of Burnout Generation due to the Instability and the Transient Change of Boiling Two-Phase Flow near a Flow Obstacle simulating a Spacer of a BWR
Grants-in-Aid for Scientific Research(基盤研究(B))
2000 - 2001
Tohru FUKANO, 渡部 正夫
A cylindrical flow obstruction which simulates a spacer supporting nuclear fuel rods in BWR was installed in the vertical annular channel. Flow patterns, especially the generation of drypatch and burnout, were carefully observed by a high speed video camera. The time variations of temperature on the heating tube surface were simultaneously measured near the spacer at six axially different location under the experimental conditions of transiently changing flow caused by the sudden change in the heart flux, the inlet quality, the mass flow rate. The effect of flow instability on the generatio...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 九州大学, Coinvestigator not use grants, Competitive research funding, 12450076 - MRアンギオグラフィーにおける血流流れ場シミュレーションと血管セグメンテーションとのレベルセット法による統合
2001
Competitive research funding - RESEARCH ON THE GENERATION MECHANISM OF BURNOUT JUST UPSTREAM OF THE SPACER SUPPORTING BWR-NUCLEAR ROD BUNDLE
Grants-in-Aid for Scientific Research(基盤研究(B))
1998 - 1999
Tohru FUKANO, 渡部 正夫
A cylindrical flow obstruction which simulates a spacer supporting nuclear fuel rods in BWR was installed in the vertical annular channel. Flow patters, especially the generation of drypatch and burnout, were carefully observed by a high speed video camera. The time variations of temperature on the heating tube surface were simultaneously measured near the spacer at six axially different locations. The results are summarized as follows.(1) Large amplitude temperature change is caused by rapid increase in heat transfer through quite thin liquid film prior to the generation of drypatch which ...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 九州大学, Coinvestigator not use grants, Competitive research funding, 10450087 - 変形気泡の相互干渉を考慮に入れた気泡群の挙動に関する流体力学的研究
科学研究費補助金(奨励研究(A))
1997 - 1998
渡部 正夫
多数の気泡を含んだ液体(気泡群)の流体力学的挙動をモデル化するために気泡相互作用・気泡変形を考慮に入れたマクロモデルの基礎となる,ミクロ要素モデルを構築することを目的とした.今年度は特に静止流体中を上昇する気泡および気泡列の挙動および周囲液体へ及ぼす影響を解明するための,基礎実験および数値解析を行った.実験においては,気泡周りの流れ場を計測するために,様々なトレーサと光源を用いることにより得られた二次元流体画像に対して,昨年度購入したグラフィックワークステーション上で開発されたPIV法による流れ場計測用処理プログラムを用いて,静止流体中における単一上昇気泡および上昇気泡列まわりの流れ場に適用した.ステレオ画像を用いることにより気泡後流の発達過程と気泡の上昇過程との相互作用を観察し,気泡変形および放出渦の相互干渉に関して知見を得た.数値計算によるアプローチにおいては,DSD/ST有限要素法を用いることにより,気泡を含む軸対称二次元流れ場を解析するための計算コードを解析し,気泡形状の変形および境界の影響に関してして調査を行った.特に可視化実験の比較対照モデルとなる2気泡の運動に関して詳細な検討を行い,同一直線上を上昇する二気泡の運動に関して数値シミュレーションを行い,気泡変形が気泡相互作用に及ぼす影響を様々な表面張力係数を用いることにより解析を行い,また,界面活性剤の影響を計算コ...
文部科学省, 奨励研究(A), 九州大学, Principal investigator, Competitive research funding, 09750197 - THERMO-FLUID DYNAMIC RESEARCH ON THE CHARACTERISTICS OF HEAT REMOVAL FROM THE NUCLEAR FUEL RODS NEAR THE SPACER
Grants-in-Aid for Scientific Research(一般研究(B), 基盤研究(B))
1995 - 1996
Tohru FUKANO, 大田 治彦, 後藤 昭和, 渡部 正夫
The effects of the geometry of the spacer, which supports the nuclear rods, on the thermo-fluid phenomena near the spacer were investigated by using two different types of the spacers. One is the ring type and the other is the grid type spacers. The special attention was focused on (a) the mechanism to cause the drypatch dormation, (b) the frequency of the drypatch formation and (c) the temperature distribution near the down side of the spacer. The results are summarized as follows.(1) Even if there is a gap between the spacer and the heating tube surface, the coolant water stagnates in bet...
Ministry of Education, Culture, Sports, Science and Technology, 一般研究(B), 基盤研究(B), 九州大学, Coinvestigator not use grants, Competitive research funding, 07455086 - 気泡群の音響特性の直接シミュレーション
Competitive research funding - 気泡運動の数値解析
Competitive research funding - Dynamic Simulation of the Acoustic Characteristics of Bubble Clouds
Competitive research funding - Thermo-Fluid Mechanical Study of the Thermoacoustic Devices
Competitive research funding - Numerical Simulation of Bubble Motions
Competitive research funding
