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Tasaka Yuji

Faculty of Engineering　Mechanical and Aerospace Engineering　Thermal and Fluid SystemsProfessor

Researcher basic information

■ Degree
  • 博士（工学）, 北海道大学
■ URL
researchmap URLホームページURL■ Various IDs
J-Global ID■ Research Keywords and Fields
Research Keyword
  • 実験流体力学
  • 流れの安定性
  • 熱対流
  • Rheometry
  • 液体金属流れ
  • 超音波計測
Research Field
  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering), Fluid engineering
■ Educational Organization

Career

■ Career
Career
  • Mar. 2024 - Present
    Hokkaido University, Laboratory for Flow Control, Division of Mechanical & Aerospace Engineering, Faculty of Engineering, Professor, Ph. D.
  • Apr. 2022 - Present
    Japan Agency for Marine-Earth Science and Technology, Data Science Research Group, Volcanoes and Earth’s Interior Research Center (VERC), Research Institute for Marine Geodynamics (IMG), Guest researcher
  • Feb. 2011 - Mar. 2024
    Faculty of Engineering, Hokkaido University, Associate Professor
  • Apr. 2017 - Jul. 2017
    Université du Havre, Laboratoire Ondes et Milieux Complexes, Visiting Researcher
  • Oct. 2016 - Jan. 2017
    Helmholtz Zentrum Dresden-rossendorf, Group of Magnetohydrodynamics, Guest scientist
  • Apr. 2007 - Jan. 2011
    Faculty of Engineering, Hokkaido University, Assistant Professor
  • Apr. 2008 - Jan. 2009
    School of Physics and Astronomy, The University of Manchester, Visiting Research Fellow
  • Apr. 2005 - Mar. 2007
    Graduate School of engineering, Hokkaido University, Research Associate
Educational Background
  • Apr. 2000 - Mar. 2005, Hokkaido University, Graduate School of Engineering, Division of Mechanical Science
Committee Memberships
  • Apr. 2025 - Present
    社団法人日本流体力学会, 理事
  • Apr. 2025 - Present
    一般社団法人日本機械学会, 流体工学部門カテゴリマネージャ, Society
  • Mar. 2026 - Feb. 2027
    一般社団法人日本機械学会, 北海道支部庶務幹事, Society
  • Apr. 2017 - Mar. 2025
    日本機械学会, 日本機械学会論文集アソシエイトエディタ, Society
  • Apr. 2020 - Mar. 2022
    一般社団法人日本機械学会, 流体工学部門講演会WG主査, Society
  • Apr. 2019 - Mar. 2020
    一般社団法人日本機械学会, 流体工学部門講演会WG幹事, Society
  • Apr. 2018 - Mar. 2020
    社団法人日本流体力学会, 代議員, Society
  • Mar. 2013 - Mar. 2019
    社団法人日本流体力学会, 編集委員, Society
  • Mar. 2013 - Feb. 2014
    社団法人日本機械学会, 北海道支部会計幹事, Society
  • Mar. 2012 - Feb. 2013
    社団法人日本機械学会, 北海道支部学生会顧問, Society
  • Apr. 2009 - Mar. 2011
    社団法人日本機械学会, 北海道支部流体工学懇話会幹事, Society
  • Oct. 2005 - Sep. 2006
    社団法人 可視化情報学会, 編集委員会 委員, Society

Research activity information

■ Awards
  • Mar. 2026, 日本機械学会北海道支部, 日本機械学会北海道支部賞（研究技術賞）
    ずり減粘のその場計測を可能にするGap Flow Testの開発
    田坂裕司・西塚大悟・大家広平・田坂裕司
  • Jul. 2024, 一般社団法人可視化情報学会, 第３５期可視化情報学会学会賞（技術賞）
    超音波パルスエコグラフィーによる管内混相流モニタリング技術
    朴炫珍;田坂裕司;村井祐一
  • Jul. 2023, 一般社団法人日本機械学会, 流体工学部門フロンティア表彰
  • Nov. 2021, 社団法人日本機械学会, 流体工学部門貢献表彰
  • Aug. 2020, 可視化情報学会, 第31期可視化情報学会 学会賞（論文賞）
    Vortex tracking on visualized temperature fields in a rotating Rayleigh-Benard convection
    能登大輔;田坂裕司;朴炫珍;柳澤孝寿;村井祐一
  • Aug. 2020, 日本混相流学会, 2019年度日本混相流学会賞 論文賞
    気液二層乱流中に発生する気泡クラスタリングの実験的解明
    大石義彦,田坂裕司,村井祐一
  • Jun. 2019, Elsevier, Outstanding contribution in Reviewing (Flow Measurement and Instrumentation)
    Yuji Tasaka
  • Sep. 2018, 可視化情報学会, 第29期可視化情報学会 学会賞（技術賞 カテゴリI）
    超音波パルスドップラーによる食品物性の定量可視化技術
    芳田泰基;田坂裕司;朴炫珍;村井祐一
  • Apr. 2017, 日本機械学会, 2016年度日本機械学会賞（技術）
    気液二相流のスマート制御に基づく船舶の乱流摩擦抵抗低減技術の実用化
    村井祐一;熊谷一郎;田坂裕司;朴炫珍;高橋義明
  • Feb. 2016, Elsevier, Outstanding reviewer (Flow Measurement and Instrumentation)
    Yuji Tasaka
  • Aug. 2015, 日本混相流学会, 2014年度日本混相流学会賞 奨励賞
    超音波流速分布計を用いた微細気泡を含む流体の実効粘度評価
    田坂裕司
  • Jul. 2014, 可視化情報学会, 第25期可視化情報学会 学会賞（論文賞）
    Development of ultrasonic visualization for capturing the characteristics of viscoelastic fluids
    白鳥貴久;田坂裕司;村井祐一;武田靖
  • Jul. 2014, 日本混相流学会, 2013年度日本混相流学会賞 技術賞
    超音波流速分布測定法（UVP）の混相流計測への拡張に関する技術開発
    村井祐一;田坂裕司;武田靖
  • Aug. 2012, 日本混相流学会, 2011年度日本混相流学会賞 論文賞
    船舶の抵抗低減の実用化・普及に向けた低負荷気泡発生機構の研究
    熊谷一郎;村井祐一;田坂裕司
  • Jul. 2010, 日本混相流学会, 2009年度日本混相流学会賞 論文賞
    気泡による摩擦抵抗低減メカニズム解明のための二相乱流構造計測
    大石義彦;村井祐一;田坂裕司;武田靖
■ Papers
■ Other Activities and Achievements
  • 速度分布情報を基にした食品の流動性評価—特集 おもしろいフルードパワーの最先端(2)
    田坂 裕司; 大家 広平; 西塚 大悟; 芳田 泰基; 熊谷 聡美; 千葉 春子, 油空圧技術 / 油空圧技術編集委員会 編, 63, 9, 23, 28, Sep. 2024
    東京 : 日本工業出版, Japanese
  • 超音波インラインレオメトリによる「おかゆ」の擬塑性変化モニタリング
    大家広平; 芳田泰基; 田坂裕司; 村井祐一, 化学工学会年会研究発表講演要旨集(CD-ROM), 89th, 2024
  • Evaluation of food swallowability by means of mechanical engineering methodology: Stability and stickiness of food bolus
    田坂裕司; 大家広平; 高橋航圭; 芳田泰基; 千葉春子; 熊谷聡美, 日本摂食嚥下リハビリテーション学会学術大会抄録集(Web), 30th, 2024
  • Rheological evaluation of liquid foods by ultrasonic velocity profiling
    大家広平; 熊谷聡美; 芳田泰基; 田坂裕司, 日本摂食嚥下リハビリテーション学会学術大会抄録集(Web), 30th, 2024
  • サスペンション流動研究のための密度調整可能な球形粒子の簡易製造方法
    大家広平; 西塚大悟; 芳田泰基; 田坂裕司, 化学工学会秋季大会研究発表講演要旨集(CD-ROM), 55th, 2024
  • 速度分布計測を基にした食品レオロジー物性の評価
    田坂裕司; 田坂裕司; 大家広平; 高野哲秀; 芳田泰基, 日本バイオレオロジー学会誌(Web), 37, 2, 2023
  • 流動計測支援型レオメトリによる食品開発・製造のDX推進
    大家広平; 芳田泰基; 田坂裕司; 村井祐一, 日本バイオレオロジー学会誌(Web), 37, 2, 2023
  • 流動計測支援型レオメータを用いた複雑流体の管内流れ予測
    大家広平; 芳田泰基; 田坂裕司; 村井祐一, 化学工学会年会研究発表講演要旨集(CD-ROM), 88th, 2023
  • 超音波インラインレオメータによる擬塑性流体の粘性評価
    田坂裕司; 芳田泰基; 大家広平; 村井祐一, 化学工学会年会研究発表講演要旨集(CD-ROM), 88th, 2023
  • 貯蔵タンク内で流体のレオロジー物性を評価するレオメータの開発
    芳田泰基; 大家広平; 田坂裕司, 化学工学会年会研究発表講演要旨集(CD-ROM), 88th, 2023
  • Functional evaluations of commercial food thickeners by ultrasonic spinning rheometry
    大家広平; 千葉春子; 熊谷聡美; 芳田泰基; 田坂裕司, レオロジー討論会講演要旨集(CD-ROM), 69th, 2021
  • レオロジーマップによる高分子溶液の多角的粘弾性評価
    大家広平; 芳田泰基; 朴げん珍; 田坂裕司; 村井祐一, 化学工学会年会研究発表講演要旨集(CD-ROM), 86th, 2021
  • 超音波流速分布計測による過渡的レオロジー物性の評価
    田坂裕司; 芳田泰基; 大家広平; 村井祐一, 化学工学会年会研究発表講演要旨集(CD-ROM), 86th, 2021
  • Efficient Air Lubrication Method on a 36-m-long Flat Plate Model Employing Repetitive Bubble Injection
    田中泰爾; 大石義彦; PARK Hyun Jin; 田坂裕司; 村井祐一; 川北千春, 日本船舶海洋工学会講演会論文集(CD-ROM), 32, 2021
  • Application of PIV-based pressure field estimation for wind tunnel and water tank experiments
    Y. Murai; Y. Tasaka; H.J. Park, The Japanese Society for Experimental Mechanics, 20, 87, 94, 2020, [Invited]
    Japanese, Introduction scientific journal
  • Visualization of artificial void waves in bubbly drag reduction experiments using a 36-m-long flat plate
    大石義彦; 中村隼人; 田中泰爾; PARK Hyun Jin; 田坂裕司; 村井祐一; 河合秀樹; 濱田達也; 若生大輔; 川北千春, 可視化情報シンポジウム(CD-ROM), 48th, 2020
  • Wall shear stress fluctuation in bubbly drag reduction for a 36-m-long flat plate
    大石義彦; 藤井夏海; 田中泰爾; PARK Hyun Jin; 田坂裕司; 村井祐一; 濱田達也; 川北千春, 日本機械学会流体工学部門講演会講演論文集(CD-ROM), 98th, 2020
  • Applicability Evaluation of In-line Rheometer based on Ultrasonic Velocity Profile Measurements
    田坂裕司; 芳田泰基; 村井祐一, 日本機械学会流体工学部門講演会講演論文集(CD-ROM), 98th, 2020
  • Effective viscosity evaluation on separating oil-water mixture by ultrasonic spinning rheometry
    大家広平; 芳田泰基; PARK Hyun Jin; 田坂裕司; 村井祐一, 日本機械学会流体工学部門講演会講演論文集(CD-ROM), 98th, 2020
  • Effective viscoelasticity affected by dispersed particles in non-Newtonian fluid under unsteady shear
    芳田泰基; 田坂裕司; 村井祐一, 日本機械学会流体工学部門講演会講演論文集(CD-ROM), 98th, 2020
  • 超音波流速分布計測を用いた複雑流体のレオロジー物性評価—Rheological Evaluations of Complex Fluids by Ultrasonic Velocity Profiling—特集 流動による流体の内部構造変化の可視化
    田坂 裕司; 芳田 泰基; 村井 祐一, ながれ : 日本流体力学会誌 = Nagare : journal of Japan Society of Fluid Mechanics, 38, 4, 283, 290, Aug. 2019
    日本流体力学会, Japanese
  • Non-invasive Inline Rheometer using Ultrasonic Velocity Profiler
    田坂裕司; 芳田泰基; 村井祐一, 日本機械学会流体工学部門講演会講演論文集(CD-ROM), 97th, 2019
  • Robustness of Savonius turbine for inflow of isotropic turbulence
    MURAI Yuichi; Otomo Shuji; TASAKA Yuji; Denissenko Petr, The Proceedings of the National Symposium on Power and Energy Systems, 2019, 0, C211, 2019
    Influence of high-intensity turbulence to the performance of a Savonious wind turbine has been investigated experimentally. The turbulent intensity and its isotropic quality are managed in a large wake region of an open-jet type wind tunnel. We have found that the rotational speed of the turbine rather increases with hep of turbulence as a constant load was subject to the turbine. This robustness to the inflow quality is attributed to the drag acting on the blade being intensified by the turbulence. Hot-wire anemometer measurement of the flow behind the turbine revealed that periodic vortex-shedding due to the blade-passing frequency was suppressed with strong turbulence in the inflow., The Japan Society of Mechanical Engineers, Japanese
  • Frictional drag reduction promoted by generating void waves in high-speed turbulent channel flows
    TANAKA Taiji; PARK Hyun Jin; TASAKA Yuji; MURAI Yuichi; KAWAKITA Chiharu, The Proceedings of the National Symposium on Power and Energy Systems, 2019, 0, A122, 2019, [Peer-reviewed]
    The Japan Society of Mechanical Engineers, Japanese
  • Rheological evaluation on liquid with dispersion bubbles under shear flow conditions
    田坂裕司; 芳田泰基; 村井祐一, 混相流シンポジウム講演論文集(Web), 2019, ROMBUNNO.F232_0026 (WEB ONLY), 2019
    Japanese
  • 回転式超音波レオメトリを用いた粘土懸濁液のレオロジー評価
    芳田泰基; 田坂裕司; PARK H. J; 村井祐一, 日本レオロジー学会年会講演予稿集, 45th, 75‐76, 17 May 2018
    Japanese
  • Rheological evaluation of non‐Newtonian effects on Newtonian fluid with dispersed bubbles
    芳田泰基; 田坂裕司; PARK Hyun Jin; 村井祐一, 混相流シンポジウム講演論文集(Web), 2018, WEB ONLY, 2018
    Japanese
  • Ultrasonic measurement of milk products flowing in stainless steel pipe
    LI Ruixue; YOSHIDA Taiki; HITOMI Jumpei; SAWADA Koki; PARK Hyun-Jin; TASAKA Yuji; MURAI Yuichi; FISCHER Stéphane, The Proceedings of the Fluids engineering conference, 2018, 0, OS4, 1, 2018
    <p>We studied a measurement using UVP (Ultrasonic Velocity Profiler) for the milk products flowing in pipe line; here, whole milk, low-fat milk and water-coffee cream were employed as samples of the milk products. Those milk products all include fat as emulsion. Although the diameter of fat particles is much smaller than suitable size of UVP tracer particles, UVP can measure velocity in the whole milk in short distance; Sufficiently large number of fat particles in the milk, however, also cause strong attenuation of ultrasonic wave. Wedge-shape wave guide was thus designed to have sufficiently strong ultrasonic wave with considering measurement in thick stainless-steel pipes, where further strong attenuation is expected.</p>, The Japan Society of Mechanical Engineers, English
  • Ultrasonic spinning rheometry
    TASAKA Yuji; YOSHIDA Taiki; PARK Hyun-Jin; MURAI Yuichi, The Proceedings of the Fluids engineering conference, 2018, 0, OS4, 2, 2018
    <p>We have developed novel rheometry using a cylindrical vessel in periodic oscillations and ultrasonic velocimetry (UVP) to overcome critical problems in conventional torque-type rheometry caused by influences of shear-banding, slips, non-homogeneous distribution of rheological properties, etc. The rheometry, termed "ultrasonic spinning rheometry", evaluates quantitatively different rheological properties, representative "local" Newtonian viscosity, shear modulus, linear viscoelasticity, through fundamental mechanical relations utilizing spatio-temporal velocity information measured by UVP. In this report, basic concept of the rheometry and its applicability and measurement limitations are summarized. Further, application of frequency-domain algorithm on linear viscoelastic analysis was described in detail.</p>, The Japan Society of Mechanical Engineers, Japanese
  • Development of a laser Doppler wall shear stress sensor for bubbly two-phase flow measurement
    Y.Oishi; S. Onuma; H. Kawai; H.J. Park; Y. Tasaka; Y.Murai, Japan-U.S. Seminar on Two-Phase Flow Dynamics 2017, 117, 120, Jun. 2017, [Peer-reviewed]
    English
  • Effect of Microbubbles on the Creation of Localized Turbulence in a Circular Pipe Flow
    中村 幸太郎; 田坂 裕司; 村井 祐一, 混相流 = Japanese journal of multiphase flow, 30, 5, 20, 28, Mar. 2017
    日本混相流学会, Japanese
  • Turbulent eddy viscosity in microbubble suspension evaluated by ultrasound spinning rheometry
    岩佐耕節; 芳田泰基; PARK Hyun Jin; 田坂裕司; 村井祐一, 混相流シンポジウム講演論文集(CD-ROM), 2017, ROMBUNNO.D113, 2017
    Japanese
  • Instability provoked by ascending bubbles in a horizontal liquid layer
    K. Nakamura; H. N. Yoshikawa; Y. Tasaka; Y. Murai, Proceedings of annual meeting of Japan Society of Fluid Mechanics, Sep. 2016, [Peer-reviewed]
    Japanese
  • Flow Metering of Multiphase Pipe Flows by Means of Ultrasound Doppler Method
    村井 祐一; 田坂 裕司, 化学工学, 80, 8, 468, 471, Aug. 2016
    化学工学会, Japanese
  • Rheometry Utilizing Ultrasonic Velocity Profiler : Importance of Flow Measurement and Propositions
    田坂 裕司; 白鳥 貴久; 芳田 泰基; 村井 祐一, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 36, 142, 103, 107,図巻頭1p, Jul. 2016
    可視化情報学会, Japanese
  • Measurement of rheological properties of fluid foods based on ultrasonic velocity profiling-Novel measuring methodology of spatial viscosity distributions-
    芳田泰基; 田坂裕司; 村井祐一, 可視化情報学会誌, 36, Suppl.1(CD-ROM), ROMBUNNO.D112, Jul. 2016
    Japanese
  • Visualization on the coupling of natural convection in three-density stratifications
    SATO Shu; TASAKA Yuji; MURAI Yuichi, The Proceedings of Conference of Hokkaido Branch, 2016, 61, 62, 2016
    The Japan Society of Mechanical Engineers, Japanese
  • An Experimental Study on a Savonius Turbine in a Turbulent Flow
    Shuji OTOMO; Susumu OSUKA; Yuji TASAKA; Yuichi MURAI; Petr DENISSENKO, The Proceedings of Conference of Hokkaido Branch, 2016.54, 0, 79, 80, 2016
    Japan Society of Mechanical Engineers
  • 浮上する気泡群の数密度構造と液相の速度場構造の相互作用について
    渡村友昭; 北川石英; 田坂裕司; 村井祐一; 杉山和靖, 混相流シンポジウム講演論文集(CD-ROM), 2016, ROMBUNNO.B122, 2016
    Japanese
  • 線形粘弾性解析による分散気泡液体のレオロジー評価
    田坂裕司; 芳田泰基; 村井祐一, 混相流シンポジウム講演論文集(CD-ROM), 2016, ROMBUNNO.B115, 2016
    Japanese
  • Toward understanding global flow structure
    Makoto Iima; Takayuki Yamaguchi; Takeshi Watanabe; Akane Kawaharada; Yuji Tasaka; Erika Shoji, Springer Proceedings in Mathematics and Statistics, 183, 139, 158, 2016, [Peer-reviewed]
    English
  • 0601 Visualization of bubble behavior beneath a model ship in large towing tank experiments
    OISHI Yoshihiko; PARK Hyun Jin; TASAKA Yuji; MURAI Yuichi, Fluids engineering conference ..., 2015, "0601, 1"-"0601-2", 07 Nov. 2015
    We carried out large-scale towing tank experiments as an open flow system to elucidate spatial development of quasi-uniformly injected bubbles. Measurement results by a shear stress sensor indicated drag reduction by injecting bubbles into turbulent boundary layer developing on a flat plate, and visualized pictures showed spontaneous development of quasi-periodic distribution of bubbles at the corresponding parameters., The Japan Society of Mechanical Engineers, Japanese
  • 1702 Experimental study of convection driven by a bubble plume in background rotation
    YOKOYAMA Soya; MURAI Yuichi; TASAKA Yuji; VLASKAMP Jop; DENISSENKO Peter; THOMAS Peter J., Fluids engineering conference ..., 2015, "1702, 1"-"1702-2", 07 Nov. 2015
    Influence of background rotation on the behavior of a bubble plume in a tank is investigated experimentally, purposing a flow control for large LNG container subject to the Earth rotation. We used the rotating tank facility in University of Warwick, and found a single air-chimney stabilized in the case of point-source of air injection. In contrast, the line-source bubble injection resists to the chimney formation and keeps planer curtain like structure. We also found eccentric oscillation of bubble plume in the disk-source type of injection., The Japan Society of Mechanical Engineers, Japanese
  • 1703 Numerical analysis and visualization of mist behavior in a horizontal pipe
    MURAI Yuichi; TASAKA Yuji; OHKUBO Jumpei; OISHI Yoshihiko; TAKEUCHI Tomoaki, Fluids engineering conference ..., 2015, "1703, 1"-"1703-2", 07 Nov. 2015
    Wavy concentrations of mist flow are observed in a horizontal pipeline as Reynolds number falls into transition regime between laminar and turbulent states. We analyzed numerically the behavior of the mist using synthetic gas phase flow structure which models turbulent puffs, and succeeded in simulating the wavy passages., The Japan Society of Mechanical Engineers, Japanese
  • J0510102 Three dimensional flow visualization of wake structure behind of a twisted Savonius turbine
    OSUKA Susumu; KOBAYASHI Hiroaki; OISHI Yoshihiko; TASAKA Yuji; MURAI Yuichi, Mechanical Engineering Congress, Japan, 2015, "J0510102, 1"-"J0510102-5", 13 Sep. 2015
    The use of Savonius type wind turbines is effective for wind from variable directions as a result of its omnidirectivity. In the past research, the wake structure of Savonius turbine has been researched for enhancing the performance. Also, it has been reported that interaction of flow among multiple Savonius turbines realized extra power generation in particular configurations. As a further advanced approach, twisted Savonius type wind turbines is now ongoing issue while being spread rapidly. However, aerodynamic characterization of the wake structure of a twisted Savonius turbines has not been established yet. The interaction of multiple twisted Savonius turbines by applying the near wake field is one of the possibilities of increasing efficiency. In this study, we focused on the vertical movement of blades of twisted Savonius turbines, and obtained the velocity vector fields on vertical cross section of the wake behind of a twisted Savonius turbine by particle tracking velocimetry (PTV) technique, and interpolated the vector fields by means of Laplace equation rearrangement (LER). As a result, it was revealed that the flow field have vertical component definitely, and flow field itself moves to flow direction with turbine rotating. In addition, vortex shedding was occurred in the vertical cross section wake structure., The Japan Society of Mechanical Engineers, Japanese
  • J0510104 Stress field visualization of flow around a wing in viscoelastic fluids
    KOBAYASHI Hiroaki; OISHI Yoshihiko; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi; WINDHAB Erich, Mechanical Engineering Congress, Japan, 2015, "J0510104, 1"-"J0510104-5", 13 Sep. 2015
    To understand the flow characteristics around a wing in viscoelastic fluids, velocity vector field of 0.50 wt% polyacrylamide (PAA) solution around a wing was obtained with particle image velocimetry (PIV). According to the velocity vector data, flow separation was vanished in lateral part of wing surface in PAA solution. To identify the mechanism of this phenomenon, streamline, shear rate, and shear strain was derived. And then first normal stress difference and shear stress were estimated by means of Kelvin-Voigt model and Lodge and Meissner formula. According to normal stress difference distribution, on the lateral part of upper surface of wing, first normal stress difference (Ni) was enhanced. First normal stress difference implies the stress balance between stress along streamline direction and stress along normal direction of streamline. Therefore, it fulfills important role in deformation such as stretching and compression. In case of positive Ni, flow element is stretched along streamline direction and compressed along normal direction of streamline. And rebound pressure against the deformation works in opposite direction of this deformation; compressing pressure in streamline direction and stretching pressure in normal direction of streamline. Thereby in this case, flow is suppressed to upper surface of wing by stretching pressure in vertical direction of streamline, which results in vanishment of flow separation., The Japan Society of Mechanical Engineers, Japanese
  • Diffusion behavior of oil mist in a horizontal pipe flow
    T.Takeuchi; Y.Oishi; I.Kumagai; Y.Tasaka; Y.Murai, Proc. 9th International Symspoium on Measurement Techniques for Multiphase Flow, 165, 166, Sep. 2015, [Peer-reviewed]
    English
  • Ultrasonic measurement of gas bubbles advecting under a ship bottom for investigating drag reduction performance
    H-J. Park; Y.Oishi; Y.Tasaka; Y.Murai, Proc. ASME-JSME-KSME Joint Fluids Engineering Conference, Jul. 2015, [Peer-reviewed]
    English
  • Color particle image velocimetry improved by decomposition of RGB distribution integrated in depth direction
    Y.Murai; N.Yonezawa; Y.Oishi; Y.Tasaka; T.Yumoto, Proc. ASME-JSME-KSME Joint Fluids Engineering Conference, Jul. 2015, [Peer-reviewed]
    English
  • Mechanisms of toroidal - spiral transitions in Taylor-Couette system with microbubble injection
    B. van Ruymbeke; Y.Murai; Y.Tasaka; Y.Oishi; C.Gabullet; C.Colin; N.Latrache; T.Ozaki, Proc. 19th International Couette-Taylor Workshop at Cottbus-Senftenberg, 72, 73, Jul. 2015, [Peer-reviewed]
    English
  • Measurement of Mass Diffusion and Turbulent Transition in Natural Gas Pipeline(In-situ fluid mechanics experiments)
    Tomoaki TAKEUCHI; Yuji TASAKA; Pipeline Technology Center Tokyo Gas Co. Ltd.; Factory of Engineering Hokkaido University, ながれ : 日本流体力学会誌 = Journal of Japan Society of Fluid Mechanics, 34, 3, 233, 239, 25 Jun. 2015
    日本流体力学会, Japanese
  • 超音波流速分布計を用いた分散混相流体の複素粘度診断
    田坂裕司; 木村拓史; RAPBERGER Richard; 大石義彦; 村井祐一; 芳田泰基, 混相流シンポジウム講演論文集(CD-ROM), 2015, ROMBUNNO.C142, 2015
    Japanese
  • Ultrasonic measurement of bubble motions in a wall boundary layer.
    H-J.PARK; Y.OISHI; Y.TASAKA; Y.MURAI, 2014 HU-SNU Symposium on Mechanical and Aerospace Engineering., 53, Nov. 2014
    English
  • 0215 Clustering of mono-dispersive bubbles in a horizontal channel flow
    OISHI Yoshihiko; TASAKA Yuji; MURAI Yuichi; TOHGE Yukihiro, Fluids engineering conference ..., 2014, "0215, 1"-"0215-2", 25 Oct. 2014
    Bubble cluster is naturally formed during the bubbles' advection in horizontal turbulent channel flows. The phenomenon cannot be mathematically modeled by the linear sum of bubble-liquid interaction, but it should be assessed with multi-scale modeling in densely dispersed bubbly flow. A series of original geometrical definitions have been proposed to characterize the bubble cluster behavior, such as statistical uniformity of spatial bubble arrangement and bubbles' radial distribution function. From the data analysis, we have found that bubble clustering remains potentially in any flow conditions including the case of large bubble-size deviation, The Japan Society of Mechanical Engineers, Japanese
  • 0213 Flow visualization of a gyromill type bubble generator
    TSUKAHARA Takahiro; HAMA Noriko; KUMAGAI Ichiro; OGATA Masayuki; TASAKA Yuji; MURAI Yuichi, Fluids engineering conference ..., 2014, "0213, 1"-"0213-2", 25 Oct. 2014
    Aimed at reducing power consumption by subsurface aerator, a gyromill type bubble generator was developed based on bubble generating hydrofoils for ship drag reduction. This device utilizes the negative pressure region generated on the surface of the rotating hydrofoil, which enables the subsurface aeration without air compression. Small air bubbles with the diameter from sub-mm to mm order were released from an air outlet of the rotating hydrofoil. In this study, the bubble generation process and the performance of the bubble generator were investigated. In particular, the influence of rotating speed, water depth, and angle of attack on the bubble volume flow rate were reported., The Japan Society of Mechanical Engineers, Japanese
  • 0520 On far wake characteristics of a horizontal axis wind turbine and permeable disks
    TASAKA Yuji; NAKASHIMA Takahiro; MURAI Yuichi; OISHI Yoshihiko, Fluids engineering conference ..., 2014, "0520, 1"-"0520-2", 25 Oct. 2014
    We dealt with the wake of a permeable disk with different solidity as a simple model to investigate an essence of wake of a wind turbine. Velocity defect at the center of the streamwise cross section of the wake was measured at each downstream position by hot-wire anemometer to characterize the wake. Variations of the velocity defect obey power law in far wake regions and the variation of the corresponding index numbers with respect to the solidity has the local maximum. It suggests there is a regime change on the vortex structure. We also investigated the wake of a model of two-blade turbine. Here the variations of the velocity defect show different tendency in far wake regions., The Japan Society of Mechanical Engineers, Japanese
  • 0202 Development of a 3D mist distribution measurement technique by Multi-layer Color PIV
    YONEZAWA Norio; OISHI Yoshihiko; TASAKA Yuji; MURAI Yuichi, Fluids engineering conference ..., 2014, "0202, 1"-"0202-2", 25 Oct. 2014
    In order to measure three-dimensional flows in large atmospheric space, we have developed a new PIV system based on Multi-layer Color PIV. This new system allows us to determine the six-layer three-dimensional velocity vector fields at a given frame rate just using a single camera view by color coded volumetric projection of light. In this paper, we developed the prototype system, and verified it by simulation of artificial 3D smoke. This system estimates the six-layer two components velocity field in three-dimensional vector field. As the result of verification, reconstructed layers and determined vectors have high correlation value with theoretic image and vector field, around the center of measurement volume. On the other hand, two problems were found. One is a fragility of pattern matching system for strong velocity gradient field. The other is increase of layer reconstruction error against low luminance pixels., The Japan Society of Mechanical Engineers, Japanese
  • 0205 Flow mechanism visualization of thermal destratification in a dam by a bubble plume
    MURAI Yuichi; KITAURA Hidekazu; TASAKA Yuji; KINO Seiji, Fluids engineering conference ..., 2014, "0205, 1"-"0205-2", 25 Oct. 2014
    Based on experimental findings in laboratory scale about the density destratification process by a bubble plume, a set of numerical simulations have been carried out. Eulerian-Lagrangian bubbly flow model equations are applied for the bubble plume to numerically replay the process in 2D and 3D geometries. Enhancement of the destratification by repetitive bubble injection (RBI) has been confirmed in 2D simulation, which is realized by wavy transport of density currents along horizontal density interfaces. The same effect in a real 3D geometry of a dam lake has been partly observed. However, complexity of the flow domain makes it obscure, implying farther study required to intensity the function of the RBI-based destratification., The Japan Society of Mechanical Engineers, Japanese
  • J0540301 Development of bird image detection system for prevention of wind turbine birdstrikes
    YOKOYAMA Soya; MURAI Yuichi; OISHI Yoshihiko; TASAKA Yuji; TAKEDA Yasushi, Mechanical Engineering Congress, Japan, 2014, "J0540301, 1"-"J0540301-4", 07 Sep. 2014
    As the number of wind turbines is increasing rapidly in the world, those pose a serious problem which rare birds impact turbine blades. It is getting more important to collect data for objective assessment of current birdstrike's problem. The authors try to offer optical base diagnosis system which detects flying birds in wind farms. The system composes of two units bird detection and bird species identification. In detection part, frame-differential method is applied to extract only birds from moving objects. In classification part, we estimate flapping frequency of birds from consecutive images so that the length scale of the bird can be estimated from aero-biological correlation. The present system allows a single-view monitoring to measure the distance of flying birds from the camera without employing stereoscopic photographing., The Japan Society of Mechanical Engineers, Japanese
  • J0510202 3-D airflow structure visualization by means of multi-layer coloring of smoke-wire technique
    KOBAYASHI Hiroaki; ODA Tomoro; OISHI Yoshihiko; Tasaka Yuji; Murai Yuichi, Mechanical Engineering Congress, Japan, 2014, "J0510202, 1"-"J0510202-5", 07 Sep. 2014
    As a new technique for visualizing three-dimensional air flow fields, multi-layer coloring of smoke-wire technique is proposed. This method is composed of four processes. (1)The specific plane of the flow is illuminated by sheet light to detect z coordinate. (2)Sheet light is shifted in z direction to detect z coordinates of the other plane of the flow and this process is repeated for whole layer of z coordinates in the measurement area. (3)To express z coordinates, the recorded gray-scaled image is colored differently in each layer. (4)The colored images are integrated into one image. In this integrated colorful image, we can understand the three-dimensional structure of the flow by the position and the color of the smoke. By means of this technique, three-dimensional flow field around a twisted Savonius wind turbine was visualized. According to the visualized image, in the convex side of the blade, the separation of attached flow is suppressed and in the concave side of the blade, with the move of the flow to +z direction, the angle of outlet flow is increased. Thereby it was concluded that twisted Savonius wind turbine is inferior in the drag characteristics and superior in the lift characteristics. This result suggests that the twisted Savonius turbines have advantages in conditions of the higher tip speed ratio, where the lift force has priority., The Japan Society of Mechanical Engineers, Japanese
  • J0510201 PTV-based Lagrangian pressure field measurement
    ODA Tomoro; OISHI Yoshihiko; TASAKA Yuji; MURAI Yuichi, Mechanical Engineering Congress, Japan, 2014, "J0510201, 1"-"J0510201-5", 07 Sep. 2014
    Needs of pressure field measurement by combining experimental results obtained by PIV and governing equations are rapidly increasing. On the other hand, PTV is one of PIV techniques, whose advantages are Lagrangian particle tracking and higher measurement resolution than PIV. In this study, we proposed the new methodology to estimate pressure distribution by using irregularly-distributed pressure gradient data. The first computing step is to calculate numerical integration to obtain pressure on the grids from scattered data points. The second step is to interpolate pressure on the scattered points by using Shepard scheme. The pressure distribution is converged by iterating these two steps. We chose Taylor-Green vortex flow as a model flow to validate the computation results. The difference of boundary conditions caused the different converged pressure value, so that it is difficult to estimate pressure with high quantitative accuracy, but it is possible to discuss the relative pressure distribution qualitatively. In addition we researched the effects of grid space, the number of referenced data and wave number for computing results by using correlation coefficient. We indicated that this method is particularly available in case of low wave number flow with high resolution grid in spite of the number of referenced data., The Japan Society of Mechanical Engineers, Japanese
  • Deformation Characteristics of a Dispersing Element in an Oscillating Shear Flow
    H.YAMAUCHI; P.DENISSENKO; Y.MURAI; Y.MIYAGISHIMA; I.KUMAGAI; Y.OISHI; Y.TASAKA, ASME 2014 4th JOINT US-EUROPEAN FLUIDS ENGINEERING DIVISION SUMMER MEETING, Aug. 2014
    English
  • Model-free rheometry based on unsteady velocity profile analysis
    T.SHIRATORI; Y.OISHI; Y.TASAKA; Y.MURAI; Y.TAKEDA, 9th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, 97, 100, Aug. 2014, [Peer-reviewed]
    English
  • Viscoelastic response of flow driven by a moving permeable disk
    T.NAKASHIMA; T.SHIRATORI; Y.OISHI; Y.TASAKA; Y.MURAI; Y.TAKEDA; E.J.WINDHAB, 9th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, 69, 72, Aug. 2014, [Peer-reviewed]
    English
  • Ultrasound detection of wall-travelling bubbles for diagnosis of drag reduction
    H-J.PARK; H.KAYUKAWA; Y.OISHI; Y.TASAKA; Y.MURAI, 9th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, 53, 56, Aug. 2014, [Peer-reviewed]
    English
  • Bubble deformation responses in oscillatory shear at high dynamic capillary numbers
    Y.MURAI; T.KIMURA; H.YAMAUCHI; Y.TASAKA; Y.OISHI, 16th International Symposium on Flow Visualization 2014 Okinawa, ISFV16-1037, 1, 13, Jun. 2014, [Peer-reviewed]
    English
  • 0623 On periodic fluctuation of wake behind a permeable disk
    NAKASHIMA Takahiro; OISHI Yoshihiko; TASAKA Yuji; MURAI Yuichi, Fluids engineering conference ..., 2013, "0623, 01"-"0623-02", 09 Nov. 2013
    Wake flow behind a permeable disk is visualized, which phenomenologically simulates far-wake aerodynamic characteristics of a horizontal axis wind turbine. Smoke wire method and hot wire anemometer are used to evaluate periodic fluctuation of the flow in the region from 5 to 25 times the disk diameter downstream to the permeable disk. The experiment has shown that there causes a significant three-dimensional spiral-like vortical fluctuation that long persists downstream within the wake. Decrease in solidity of the permeable disk, thus, increase in aerodynamic permeability of the wind turbine, lowers Strouhal number for primary frequency of the velocity fluctuation and decreases the time averaged velocity and turbulence intensity of wake behind the disk., The Japan Society of Mechanical Engineers, Japanese
  • 0312 Maintained void rate fluctuation by periodic bubble injection
    PARK Hyun Jin; OISHI Yoshihiko; TASAKA Yuji; MURAI Yuichi, Fluids engineering conference ..., 2013, "0312, 01"-"0312-04", 09 Nov. 2013
    In the frictional drag reduction using bubbles, we proposed a periodic bubble injection technique to improve the performance and the new technique improved the performance 66% in Re 2200 at a horizontal channel flow. In this paper, the void fraction fluctuation in higher Reynolds number condition is investigated by visualization. The uncontrolled fluctuation of the void fraction fluctuation doesn't have any specific frequency, however the artificial fluctuation of void fraction maintain its frequency in streamwise. We indicate that it is possible to control density and shape of a swarm of bubbles by controlling the injection frequency and gas volume., The Japan Society of Mechanical Engineers, Japanese
  • 0202 Destruction of broad density stratification by means of a bubble plume
    MURAI Yuichi; KAYUKAWA Hirohide; KITAURA Hidekazu; OISHI Yoshihiko; TASAKA Yuji; KINO Seiji, Fluids engineering conference ..., 2013, "0202, 01"-"0202-02", 09 Nov. 2013
    Experimental and numerical flow visualizations on density destratification process provided by a bubble plume in horizontally long environment are presented. The experiment has shown that the initial density stratification can be broken broadly by creation of intermediate density layer inside turbulent bubble plume since the intermediate layer naturally induce density current in the horizontal direction. The process has been simulated in a 2-D rectangular tank, which further revealed that oscillation of bubble plume promoted the current. 3-D simulation applied for a dam has shown activation of destratification by the intermediate density layer regardless of geometry of the dam., The Japan Society of Mechanical Engineers, Japanese
  • 0201 Large deformation characteristics of a droplet in oscillating shear flow
    YAMAUCHI Hideaki; MIYAGISHIMA Yoshihito; KUMAGAI Ichiro; OISHI Yoshihiko; TASAKA Yuji; MURAI Yuichi, Fluids engineering conference ..., 2013, "0201, 01"-"0201-02", 09 Nov. 2013
    The aim of this study is to clarify the large deformation characteristics of a droplet in oscillating shear flow. Oscillating shear flow is generated between parallel plates which move opposite directions with sinusoidal waveform with motor sliders. A droplet is set between two plates and it receives shear stress from the plates. A deformed droplet is illuminated by green-laser sheet light and its shape is recorded by a high-speed video camera. The experimental results show that time variations of deformation parameter D have viscoelastic response to strain. Phase advance of maximum deformation parameter to strain θ_ was described as a function of maximum capillary number Ca_., The Japan Society of Mechanical Engineers, Japanese
  • 0214 Monitoring of gas-liquid two-phase flows in a horizontal channel with Ultrasonic Velocity Profiler
    KAYUKAWA Hirohide; Park Hyun Jin; OISHI Yoshihiko; TASAKA Yuji; MURAI Yuichi, Fluids engineering conference ..., 2013, "0214, 01"-"0214-02", 09 Nov. 2013
    In the frictional drag reduction by using bubbles, fluctuations of void fraction take an important role to enhance the effect. We have investigated the mechanisms on formation of bubble clusters that provide the large fluctuation. The objective of this study is establishing a new measurement system of passing interval of bubbles with ultrasonic wave in order to find out the property of void fluctuation. We conducted synchronous measurement of ultrasonic pulse emission and video camera recording of bubble images in a horizontal bubbly channel flow. The present technique provided reasonable results on the passing interval in comparison with the estimates from the images. Probability distributions of the passing bubbles obtained at three different points in the downstream represent influence of bubble coalescence., The Japan Society of Mechanical Engineers, Japanese
  • 0215 Optimization of a hydrofoil bubble generator for ship drag reduction
    KUMAGAI Ichiro; SAKAMAKI Haruki; OZAKI Yutaka; OISHI Yoshihiko; TASAKA Yuji; MURAI Yuichi, Fluids engineering conference ..., 2013, "0215, 01"-"0215-02", 09 Nov. 2013
    In order to reduce the energy necessary for supplying air bubbles for ship drag reduction, we propose two types of devices for bubble generators using hydrofoils. One is the winged air induction pipe (WAIP), which has an angled hydrofoil with an air introducer, utilizes the low-pressure region produced above the hydrofoil as the ship moves forward, which drives atmospheric air into water. Another type of bubble generator is the device that consists of hydrofoils with air holes provided on their surface. Small bubbles are generated from the air holes when the hydrofoil moves to create low pressure region around the air hole. In this presentation we describe the principles of bubble generation processes based on a simple fluid dynamic theory and on towing tank experiments. We also report the optimization of the hydrofoil bubble generators using flaps., The Japan Society of Mechanical Engineers, Japanese
  • Effective Viscosity of Bubbly Liquid Accompanied by Non-Equilibrium Bubble Deformations
    T.KIMURA; T.SHIRATORI; Y.OISHI; I.KUMAGAI; Y.TASAKA; YMURAI, The 12th International Symposium on Fluid Control, Measurement and Visualization (FLCOME2013), OS8-03-1, USB, Nov. 2013, [Peer-reviewed]
    English
  • Characterization of Viscoelasticity from Complex Flows with Shear and Extension
    T.SHIRATORI; Y.OISHI; Y.TASAKA; Y. MURAI, The 12th International Symposium on Fluid Control, Measurement and Visualization (FLCOME2013), OS8-04-2, USB, Nov. 2013, [Peer-reviewed]
    English
  • 1064 SIMULTANEOUS MEASUREMENTS OF VELOCITY AND TEMPERATURE FIELDS MODIFIED BY A THERMAL BLOB INJECTING INTO A LIQUID METAL LAYER
    Yuji Tasaka; Kazuto Igaki; Ichiro Kumagai; Yuichi Murai, Jets, wakes and separated flows : proceedings of International Conference on Jets, Wakes and Separated Flows, ICJWSF, 2013, 4, "1064, 1"-"1064-5", 16 Sep. 2013
    A novel technique to measure temperature and velocity fields in liquid metal layer was proposed to understand localized fluid motions accompanied by heat transfer. A thin fluid layer of liquid gallium was adopted to simplify the fluid motion, and a sheet of thermo-chromic liquid crystal paint and ultrasonic velocity profiling provided visualization of temperature and velocity fields. Flows due to injection of small blobs of liquid gallium into the liquid gallium layer were investigated to demonstrate and evaluate the measurement technique and the setup., The Japan Society of Mechanical Engineers, English
  • J054012 Measurement of Flow Structure around a Wind Tunnel Model VAWT by PIV
    ODA Tomoro; OISHI Yoshihiko; TASAKA Yuji; MURAI Yuichi, Mechanical Engineering Congress, Japan, 2013, "J054012, 1"-"J054012-5", 08 Sep. 2013
    Vertical-axis wind turbines (VAWTs) have been attracting attention in recent years because of omnidirectivity. Namely they can start to rotate by wind from all directions. Moreover it has been reported that interactive flow field of two VAWTs increases the total output power. However an arrangement of two VAWTs loses omnidirectivity that is the great advantage of a VAWT. In order to reduce the disadvantage, we focused on controlling wake of a VAWT by modifying its blade setting angle. We made some small turbine models which have different blade setting angle (θ= 0,3,6 and 9), and conducted a visualization experiment in wind tunnel. After that velocity distribution was calculated by particle image velocimetry (PIV). As a result it was clarified that in the case of θ=6 and 9°, velocity defect area was reduced. This result indicates that it is possible to install VAWTs in further close proximity. Moreover it was revealed that in the case of θ= 0 and 3°, vortex shedding occurred at the forward blade, but in case of θ=6 and 9°, it did not. In this experiment we conclude that change of wake structure by modification of blade setting angle spreads variations of arrangements without performance degradation of the turbine which is installed in downstream., The Japan Society of Mechanical Engineers, Japanese
  • J054021 Spatial reconstruction of flow field induced in rotating system using off-axis measurement
    MURAI Yuichi; SHIRATORI Takahisa; TASAKA Yuji; Vlaskamp Jop, Mechanical Engineering Congress, Japan, 2013, "J054021, 1"-"J054021-5", 08 Sep. 2013
    Measurement of velocity distribution in flows requires multi-dimensional setup when the flow behaves on fully three-dimensional and unsteady manner. Experimentalists, therefore, often need an effort to acquire the quantitative flow field information with limited instrumentation that only measure flow velocity in partial dimension or restricted components. UVP (ultrasound velocity profiling technique) and PIV (particle image velocimetry) are categorized to 1C-1D and 2C-2D velocity measurement as their first principle while extension of the system for upper dimensional measurement is ongoing for the both cases. In this study, the methodology of the application of UVP and PIV to three-dimensional flow field without any introduction of additional hardware system is presented, and demonstrated with several representative flow fields which show unique features of rotating fluid mechanics. The method is commonly based on off-axis measurement of flow field, which allows 3-D flow field to be scanned by relative frame rotation between the velocity profiling line and the rotating flow structure., The Japan Society of Mechanical Engineers, Japanese
  • J057015 Influences of imperfections on a turbulent flow transition in a rotating flow with free surface
    TASAKA Yuji; IIMA Makoto; KAWAHARADA Akane, Mechanical Engineering Congress, Japan, 2013, "J057015, 1"-"J057015-5", 08 Sep. 2013
    Rotating flows in a cylindrical open vessel show dynamic surface deformations between an axisymmetric and a non-axisymmetric shape accompanied by laminar-turbulent transitions of the global flow structure. Appearance of the dynamic surface deformation, termed surface switching in series of our papers, depends on the apparatus and a more precise system has a tendency to reduce frequency of appearance of the surface switching. The aim of this study is to clarify influences of imperfections of the flow system on the flow transition. We prepared three disks having different gap size against the cylinder wall and an elliptic disk for the rotor with expecting difference on noise generation in the flow system. As our expectation the disk with wider gap increases the appearance of surface switching. And a statistical analysis on the corresponding surface height variation suggests that the surface switching is a random event due to gap flow noise. Using the elliptic disk enhances the flow instability for axi-symmetry breaking on the free surface and leads toward the surface switching. But after the switching occurs, the disk affects to stabilize the surface motion., The Japan Society of Mechanical Engineers, Japanese
  • A124 Wind tunnel model experiments on interaction among horizontally arranged VAWTs
    MURAI Yuichi; ODA Tomoro; OISHI Yoshihiko; TASAKA Yuji, National Symposium on Power and Energy Systems, 2013, 18, 29, 30, 19 Jun. 2013
    As for fundamental understanding of densely arranged vertical axis wind turbines expected in future, wind tunnel model experiments are carried out to find out the aerodynamic interaction between two wind turbines With PIV measurement of time-dependent flow field, the interaction mechanism is deduced, which is classified into near-field interaction due to pressure-field coupling, and far-field interaction due to mean velocity distribution Savonius and Darrieus turbines are compared, and we have found different interaction mechanism between them Savonius turbine, which rotates at tip-speed ration less than unity, produces a dynamic pressure fluctuation to enhance the near-field interaction In contrast, two Darrieus turbines interact with shear layer released by rotating blade at high tip-speed ratio, The Japan Society of Mechanical Engineers, Japanese
  • F113 Improvement of Hydrofoil Performance on Air Bubble Entrainment for Drag Reduction of Ships
    KUMAGAI Ichiro; SAKAMAKI Haruki; TASAKA Yuji; OISHI Yoshihiko; MURAI Yuichi, National Symposium on Power and Energy Systems, 2013, 18, 187, 188, 19 Jun. 2013
    We have investigated flow behaviour around a moving hydrofoil beneath an air-water interface in order to optimize the hydrofoil facility of bubble generation for drag reduction of ship. Experimental results of flow visualization show that the deformation characteristics of the air-water interface depend on the occurrence of the flow separation over the hydrofoil. The attachment of the flaps to the hydrofoils causes significant deformation of the air-water interface in the downstream, which induces wave breaking and results effective bubble generation. On the other hand, we could not observe the effective bubble generation by the vortex generators because the magnitude of the free surface deformation becomes small due to turbulent flow., The Japan Society of Mechanical Engineers, Japanese
  • Flow Visualization and Characterization of non-Newtonian fluids by UVP
    白鳥 貴久; 大石 義彦; 田坂 裕司, 可視化情報学会誌 = ournal of the Visualization Society of Japan, 33, 1, 411, 414, 2013
    可視化情報学会, Japanese
  • 0505 Non-equilibrium deformation of a drop in an oscillatory shear flow
    MIYAGISHIMA Yoshihito; Denisenco Petr; KUMAGAI Ichiro; TASAKA Yuji; MURAI Yuichi, Fluids engineering conference ..., 2012, 215, 216, 16 Nov. 2012
    Non-equilibrium deformation of a droplet in an oscillatory shear flow was investigated. Two plates which are set parallel to each other are moved as opposite phase oscillation to make the shear flow. The flow behavior was visualized by High Speed Video-camera with laser light sheet. Silicone oil of 10,000 cSt and Glycerin aqueous solution are used as continuous phase and dispersed phase respectively. We measured the deformation parameters such as D and diot flow direction of a droplet and have compared the non-equilibrium deformation response with the equilibrium one to obtain the relationship between the deformation of a droplet and the transient shear flow., The Japan Society of Mechanical Engineers, Japanese
  • 0509 Experimental CFD-hybrid Analysis of a Horizontally Moving Object beneath Water Surface
    MURAI Yuichi; KUMAGAI Ichiro; TASAKA Yuji; OISHI Yoshihiko; OYABU Koji, Fluids engineering conference ..., 2012, 223, 224, 16 Nov. 2012
    Flow induced by a moving object beneath free surface is investigated by means of EFD-CFD hybrid analysis. Free surface profiles from experimental images are coupled with 2-D Navier-Stokes simulation in order to obtain the internal liquid flow structure that takes place during two-way interaction between free surface motion and the wake structure of the objects. Targeting of two types of objects, a circular cylinder and an elliptic hydrofoil, their drag and lift coefficients being modified by the presence of free surface have been estimated and discussed., The Japan Society of Mechanical Engineers, Japanese
  • 0504 Plume's rhythm:nonlinear oscillation of the flow in deformable gel beads
    KUMAGAI Ichiro; MURAI Yuichi; TASAKA Yuji; WATAMURA Tomoaki; KURITA Kei, Fluids engineering conference ..., 2012, 213, 214, 16 Nov. 2012
    We have conducted laboratory experiments on spatio-temporal evolution of laminar plumes in a deformable gel beads layer. A thin experimental tank is filled with the mixture of deformable gei beads and a sugar syrup solution as the interstitial fluid. The buoyant plumes are generated by injection of a viscous fluid from a thin slit. When we injected a buoyant fluid, a gravitational instability like Rayleigh-Taylor instability occurs; Then the flow is localized and buoyant plumes are generated. The plume flow is relatively continuous at the source region, however, flow instability occurs along the plume axis and the pulsating flow is developed., The Japan Society of Mechanical Engineers, Japanese
  • 0508 Behavior of bubble clustering under a drag reduction condition in a horizontal channel flow
    OISHI Yoshihiko; TOHGE Yukihiro; TASAKA Yuji; MURAI Yuichi, Fluids engineering conference ..., 2012, 221, 222, 16 Nov. 2012
    Experimental investigation on drag reduction by air bubble injection is carried out to elucidate the influence of bubble clustering in a horizontal rectangular channel. Silicone oil is used as working fluid so that experimental uncertainty due to contamination is removed particular for the clustering phenomenon. Bubbles formed chained arrangement in the streamwise direction on laminar flow states, and disperse isotropically on turbulent states. Such a bubble clustering behavior is analyzed quantitatively with image processing to obtain probability distribution of the nearest bubbles., The Japan Society of Mechanical Engineers, Japanese
  • 0516 Statistical Measurement of Particle-Gas Two-Phase Turbulent Flow in Horizontal Cylindrical Pipe
    TAKEUCHI Tomoaki; TORIUMI Ryoichi; TASAKA Yuji; Kumagai Ichiro; Murai Yuichi, Fluids engineering conference ..., 2012, 237, 238, 16 Nov. 2012
    The statistical measurement of particles behavior in horizontal cylindrical pipe has been conducted by means of PTV technique. The results suggest that with increasing the gas velocity the behavior of particles shifts from creep or short range saltation to long range saltation or continuous suspension. It is also indicated that the force acting on the particles in boundary layer plays an important role to determine the flow regime of particles., The Japan Society of Mechanical Engineers, Japanese
  • 305 Visualization of behavior of microbubbles in a boundary layer
    OISHI Yoshihiko; MURAI Yuichi; TASAKA Yuji, 北海道支部講演会講演概要集, 2012, 51, 85, 86, 20 Oct. 2012
    The Japan Society of Mechanical Engineers, Japanese
  • 312 Tidal influence simulation of bubble-drag reduction ship
    MURAI Yuichi; TASAKA Yuji; OISHI Yoshihiko; TAKAHASHI Yoshiaki, 北海道支部講演会講演概要集, 2012, 51, 97, 98, 20 Oct. 2012
    The Japan Society of Mechanical Engineers, Japanese
  • 311 Experimental study on a bubble generator with rotating hydrofoils
    Sato Keiya; Kumagai Ichiro; Oishi Yoshihiko; Tasaka Yuji; Murai Yuichi, 北海道支部講演会講演概要集, 2012, 51, 95, 96, 20 Oct. 2012
    The Japan Society of Mechanical Engineers, Japanese
  • J055022 Single Camera-based Global 3-D Particle Image Velocimetry for Airflows
    YUMOTO Takeaki; WATAMURA Tomoaki; TASAKA Yuji; KUMAGAI Ichiro; MURAI Yuichi, Mechanical Engineering Congress, Japan, 2012, "J055022, 1"-"J055022-5", 09 Sep. 2012
    3-D PIV applying tomographic reconstruction technique of smoke concentration pattern in a 3-D measurement volume has adopted for large scale airflows. The measurement system is composed of a liquid-crystal display projector for the color-coded volumetric illumination and a single camera for capturing RGB color intensity components of misty tracers. The 3-D tracer concentration pattern is obtained from the RGB color intensity components. In this paper, we applied Color PIV to large measurement volume in airflows. Measurement volume is unrestricted by the spatial resolution of a camera because smoke concentration profiles are used for reconstruction. For the application of this technique, flow fields of elliptical vortex ring and wake of a delta wing were measured. Flow fields reconstructed by our technique were appropriately measured even if flow patterns were quite different in each layer., The Japan Society of Mechanical Engineers, Japanese
  • 309 Lagrangian Frame PTV on the interference between a free surface and vortex shedding from a circular cylinder
    Oyabu Koji; Kumagai Ichiro; Tasaka Yuji; Murai Yuichi, 北海道支部講演会講演概要集, 2011, 50, 95, 96, 01 Oct. 2011
    The Japan Society of Mechanical Engineers, Japanese
  • 311 Detection and distinction of birds for Bird Strike by image analysis
    TAKESHIMA Kotaro; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, 北海道支部講演会講演概要集, 2011, 50, 99, 100, 01 Oct. 2011
    The Japan Society of Mechanical Engineers, Japanese
  • 310 Reconstruction of 3-D smoke density distribution for Color Particle Image Velocimetry applied to 3-D measurement of airflows
    YUMOTO Takeaki; WATAMURA Tomoaki; TASAKA Yuji; MURAI Yuichi, 北海道支部講演会講演概要集, 2011, 50, 97, 98, 01 Oct. 2011
    The Japan Society of Mechanical Engineers, Japanese
  • 316 Assessment for relationships between velocity fluctuations of propeller wind turbine wakes and low-frequency noise
    NAKASHIMA Takahiro; TAKESHIMA Kotaro; TASAKA Yuji; MURAI Yuichi, 北海道支部講演会講演概要集, 2011, 50, 109, 110, 01 Oct. 2011
    The Japan Society of Mechanical Engineers, Japanese
  • 314 Rheological parameter estimation for viscoelastic fluids on flow field analyses
    SHIRATORI Takahisa; KUMAGAI Ichiro; TASAKA Yuji; MURAI Yuichi, 北海道支部講演会講演概要集, 2011, 50, 105, 106, 01 Oct. 2011
    The Japan Society of Mechanical Engineers, Japanese
  • J055015 Visualization of pumping principle of a Trochoid gear pump for Non-Newtonian fluids
    AIKAWA Yuki; SHIRATORI Takahisa; TASAKA Yuji; MURAI Yuichi; MIYAGI Naoki, Mechanical Engineering Congress, Japan, 2011, "J055015, 1"-"J055015-5", 11 Sep. 2011
    Flow inside a Trochoid gear pump for microbubble fluids is visualized using Kalliroscope flakes to grasp the effect of adding microbubbles on the flow structure. Upon taking phase-statistics for the time serial images, average brightness and standard deviation varying with Reynolds number are obtained. At Re = 2000, the turbulence occurs due to jets of counter flow in enclosed unit. The turbulence is, however, alleviated by the addition of microbubbles: turbulent component is weakened by adding microbubbles. Critical Reynolds number for turbulent flow transition is increased by adding microbubbles. It indicates that the pump volume efficiency may be improved by keeping the laminar flow state in the enclosed unit even at higher Reynolds numbers than in single phase conditions., The Japan Society of Mechanical Engineers, Japanese
  • H102 Optimization of Hydrofoil Air Pump for Reduction of CO_2 Emissions from Ships
    KUMAGAI Ichiro; OYABU Koji; KUSHIDA Takafumi; MURAI Yuichi; TASAKA Yuji; TAKAHASHI Yoshiaki, National Symposium on Power and Energy Systems, 2011, 16, 191, 192, 22 Jun. 2011
    We have invented a new power-saving device for ship drag reduction by microbubbles in order to reduce the CO_2 emissions from ships. The new device, which consists of angled hydrofoils with air introducers, has been installed on a coaster and 〜10% net power saving is achieved. This device utilizes a low-pressure region produced above the hydrofoil as the ship moves forward, which drives the atmospheric air into the water. Here we present its principal and optimization of the device based on laboratory experiments on hydrofoils moving beneath a free surface. Especially, the flow behaviors of the entrainment through the interface and bubble formation process are discussed., The Japan Society of Mechanical Engineers, Japanese
  • D203 Control of angle of attack for Darrieus blades by cylindrical elements
    TAKESHIMA Kotaro; TASAKA Yuji; MURAI Yuichi, National Symposium on Power and Energy Systems, 2011, 16, 347, 350, 22 Jun. 2011
    Since Darrieus turbine is omnidirectional against the wind, it has a great essential advantage in turbulent wind environment. However, the disadvantage is known on the starting up in low velocity conditions of the wind, compared with Propeller turbines. In this study, a new technique to improve the efficiency is proposed by providing a large internal cylinder rotating together with the blades, which can control the angle of attack of the blades. The influence of cylindrical diameter on the blade performance is evaluated from the wake of the turbine. The flow field around the blades is measured by Particle Image Velocimetry. Moreover, the change of angle of attack and lift coefficient are calculated from the measured relative velocity vector field. As a result, the change of angle of attack and lift coefficient are improved in a limited range of rotating angle., The Japan Society of Mechanical Engineers, Japanese
  • D206 Wind fluctuation field and low-frequency noise formed around vertical axis wind turbines
    MURAI Yuichi; TANAKA Daiki; SHIGETOMI Akinari; TAKESHIMA Kotaro; TASAKA Yuji; XIN Wen, National Symposium on Power and Energy Systems, 2011, 16, 355, 358, 22 Jun. 2011
    Flow noise of wind turbines is already on serious stage that starts to restrict the spread of wind power generation. For vertical axis wind turbines for urban area, the noise-causing mechanism is more important to be clarified because of near-distance impact to people. We measured flow fields around several models of blades using particle image velocimetry and hot wire velocimetry in order to evaluate the type and the source of flow noise in the case of vertical axis wind turbines., The Japan Society of Mechanical Engineers, Japanese
  • 302 Spatio-temporal development of two-dimensional microbubble plumes
    MIYAGISHIMA Yoshihito; WATAMURA Tomoaki; TASAKA Yuji; MURAI Yuichi, 北海道支部講演会講演概要集, 2010, 49, 53, 54, 07 Nov. 2010
    The Japan Society of Mechanical Engineers, Japanese
  • 407 Water height detection in open channel flows using ultrasonic velocity profiling
    SAKURAI Kosuke; TASAKA Yuji; MURAI Yuichi; SCHMITT Philippe; FISCHER Stephane; PALLARES Anne, 北海道支部講演会講演概要集, 2010, 49, 91, 92, 07 Nov. 2010
    The Japan Society of Mechanical Engineers, Japanese
  • 0124 Unsteady Aerodynamics of a Turning Blade
    TANAKA Daiki; TASAKA Yuji; MURAI Yuichi, Fluids engineering conference ..., 2010, 53, 54, 29 Oct. 2010
    A blade which has fluctuating pitch angle influences on the air field around itself. The purpose of this study is to investigate unsteady aerodynamics which acts on a turning plate by Particle Image Velocimetry (PIV). This technique makes us possible to access the flow field around the fluctuating pitch angle of the blade. Comparison of the flow fields between a turning flat plate and non-turning flat plate indicates drastic differences even in the same attack angle; i.e. flow direction, appearance of the flow separation, width of the wake and so on. Phase averaged velocity distribution in a range of the angle shows periodic generation of vortex., The Japan Society of Mechanical Engineers, Japanese
  • 0905 Vortex shedding from a moving cylinder beneath a free surface : The behavior of the Strouhal number with water depth
    OYABU Koji; KUMAGAI Ichiro; TASAKA Yuji; MURAI Yuichi, Fluids engineering conference ..., 2010, 243, 244, 29 Oct. 2010
    We have conducted laboratory experiments on the flow past a circular cylinder moving beneath an air-water interface. The vortex street and the free surface profile are visualized for Reynolds number between 200 and 15,000 and for Froude number between 0.01 and 3.2. At large Reynolds number (> 10,000), the surface deformation becomes substantial in the downstream of the cylinder and bubble injection is observed. The Strouhal-Reynolds number relationship with gap ratio between 0.25 and 2.0 which shows the period of the vortex shedding becomes long when the gap ratio is small., The Japan Society of Mechanical Engineers, Japanese
  • G310 Dynamics of a vortex ring impacting a solid boundary in a rotating fluid
    Nambu Yuichi; Tasaka Yuji; Murai Yuichi, Fluids engineering conference ..., 2010, 571, 572, 29 Oct. 2010
    Vortex ring impacting a solid boundary in a rotating fluid has been visualized by dye to know the effect of rotation to its circumferential instability. Decrease in centerline ejection velocity has been observed due to the existence of background rotation. However, the number of waves of vortex ring in rotating fluid which are generated when it impacts a solid wall was almost same as that of without any background rotation. This result shows the number of waves of vortex ring which can be estimated by the initial condition is reproduced when it impacts a solid boundary even though the effect of rotation exists in the flow., The Japan Society of Mechanical Engineers, Japanese
  • 1901 Ultrasonic measurement of rotating flow fields with free surface deformation
    TASAKA Yuji; MURAI Yuichi; IIMA Makoto, Fluids engineering conference ..., 2010, 521, 522, 29 Oct. 2010
    We investigate a surface shape and a flow field around the surface in the temporally irregular surface switching of rotating fluids to clarify the mechanism of the phenomenon. Interface detection and estimation of two-dimensional velocity field from spatio-temporal velocity distributions successfully represent an elliptic surface shape and flow mixing due to the rotating surface., The Japan Society of Mechanical Engineers, Japanese
  • 1605 Measurement of the viscoelastic flow around a falling sphere
    SHIRATORI Takahisa; TASAKA Yuji; MURAI Yuihci, Fluids engineering conference ..., 2010, 465, 466, 29 Oct. 2010
    Velocity vector field of 1.0 wt% polyacrylamide (PAA) solution around a falling sphere was obtained with particle image velocimetry (PIV). Paths of fluid particles were calculated according to the obtained velocity field. Particles near the falling sphere are driven to downward at first. After that the particles come back to almost initial position while forming negative wake. Vibrations of the particles were observed before the particles settle terminal position. The amplitude, center and frequency of the vibration depend on the distance between the fluid particle and the path of the sphere., The Japan Society of Mechanical Engineers, Japanese
  • 超音波流速分布計による流動モニタリング技術の新展開
    武田 靖; 田坂 裕司; 村井 祐一, 化学工学 = Chemical engineering, 74, 8, 381, 384, 05 Aug. 2010
    化学工学会, Japanese
  • A101 Development of Bell-shaped Compact Type Savonius-Darrius Hybrid Wind Turbine
    Ooasa Kouichi; Souma Sadahiro; Tasaka Yuji; Murai Yuichi, National Symposium on Power and Energy Systems, 2010, 15, 1, 2, 20 Jun. 2010
    Interaction between Savonius turbine and Darrius turbine as they rotate coaxially in uniform inflow is investigated experimentally. When they are arranged closely with the tip-radius ratio of 2.5, Darrius-to-Savonius interaction is examined by measuring the change of rotational speed relative to isolated Savonius turbine in uniform flow. Its inverse, i.e. Savonius-to-Darrius interaction, is evaluated by lift force of the blade subjected to flow around Savonius turbine measured by PIV. The results have shown that the Savonius-to-Darrius interaction provides improvement of Darrius turbine performance at middle range of tip-speed ratio. Therefore, hybridization of these two turbines is concluded to be suitable not only in artistic designing for realizing compact design, but also in the aspect of fluid dynamics., The Japan Society of Mechanical Engineers, Japanese
  • Turbulent Frictional Drag Reduction Promoted by Passive and Active Fluctuation in Void Fraction
    Murai Yuichi; Tasaka Yuji, 日本流体力学会年会講演論文集, 2010, 159, 159, 2010
    We have found a significant promotion of turbulent frictional drag reduction when the void fraction of bubbles injected into the boundary layer involves temporal fluctuation. The fluctuation is induced naturally when the two-phase shear flow develops spatially in the streamwise direction. By providing the fluctuation artificially with repetitive bubble injection (RBI-technique), we have succeeded in expanding the drag reducible range regarding mean void fraction. The experimental facts demonstrating the fluctuation's effect and simplified mathematical description are reported here., 日本流体力学会, Japanese
  • PIV measurement of 3D structure of Taylor Column
    Nambu Yuichi; Tasaka Yuji; Murai Yuichi; Vlaskamp J. H. A.; Thomas P. J., 日本流体力学会年会講演論文集, 2010, 170, 170, 2010
    Off axis PIV approach has been introduced to obtain 3 dimension 3 component velocity vector field of Taylor column. This method makes it possible to reconstruct vector field by a single camera setting because its PIV measurement plane surface is slightly offset toward rotating axis. This approach was applied to Taylor Column which has circumferential instability. The fully reconstructed vector field shows the structure of Taylor column twist around the rotating axis as the distance from the disk increase., 日本流体力学会, Japanese
  • Intermittent bubble injection by the oscillating Jet: the interference between a free surface and flow past a submerged cylinder
    KUMAGAI Ichiro; OYABU Takeshi; TASAKA Yuji; MURAI Yuichi, 日本流体力学会年会講演論文集, 2010, 17, 17, 2010
    We have conducted laboratory experiments on the flow past a circular cylinder moving at a constant speed U_0 beneath an air-water interface. The vortex street and the free surface profile are visualized for Reynolds number (Re=Ud/v) between 200 and 15,000 and for Froude number (Fr_h=U_0/(hg)^<1/2>) between 0.01 and 3.2 (d and h are the diameter of the cylinder and the distance between the top of the cylinder and the undisturbed water surface, respectively). At large Reynolds numbers (>10^4), the surface deformation becomes substantial in the downstream of the cylinder and intermittent bubble injection by a jet-like flow is observed. We have also investigated variation of the Strouhal-Reynolds number relationship with gap ratio (a=h/d) between 0.25 and 2.0, which shows the period of the vortex shedding becomes long when the gap ratio is small., 日本流体力学会, Japanese
  • 回転流体自由界面の不規則スイッチングにおける底面-側壁ギャップの影響
    田坂 裕司; 飯間 信; 佐藤 讓, 日本流体力学会年会2010拡張要旨集, 2010
    Japanese
  • 回転流体系実験時系列からのランダム力学系の抽出
    佐藤 讓; 飯間 信; 田坂 裕司, 第59回理論応用力学講演会講演論文集, 145, 146, 2010
  • 回転流体における自由表面の遷移動力学の解析
    飯間 信; 飯島 悠宇; 佐藤 讓; 田坂 裕司, 第59回理論応用力学講演会講演論文集, 143, 144, 2010
  • 215 CT Visualization with Dome Mirror Camera
    TANAKA Daiki; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, 北海道支部講演会講演概要集, 2009, 48, 63, 64, 28 Nov. 2009
    The Japan Society of Mechanical Engineers, Japanese
  • 216 PIV measurement of circumferential flow structure of Taylor column
    NAMBU Yuichi; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi; VLASKAMP Jozef; THOMAS Peter J., 北海道支部講演会講演概要集, 2009, 48, 65, 66, 28 Nov. 2009
    The Japan Society of Mechanical Engineers, Japanese
  • 214 Ultrasonic investigation of oscillating pipe flow of viscoelastic fluid
    OYAMA Kazuya; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, 北海道支部講演会講演概要集, 2009, 48, 61, 62, 28 Nov. 2009
    The Japan Society of Mechanical Engineers, Japanese
  • 212 Interactive Flow of Savonius Turbines Arranged in Horizontal Plane
    SHIGETOMI Akinari; MURAI Yuichi; TASAKA Yuji; TAKEDA Yasushi, 北海道支部講演会講演概要集, 2009, 48, 57, 58, 28 Nov. 2009
    The Japan Society of Mechanical Engineers, Japanese
  • 203 Vortex Shedding from a Bluff-body Beneath a Free Surface : Effect of the Shape of the Body on the Surface Distortion and Bubble Generation
    NAKAMURA Naoya; KUMAGAI Ichiro; MURAI Yuichi; TASAKA Yuji; TAKEDA Yasushi, 北海道支部講演会講演概要集, 2009, 48, 39, 40, 28 Nov. 2009
    The Japan Society of Mechanical Engineers, Japanese
  • 204 Effect of microbubbles on Taylor-Couette flow
    WATAMURA Tomoaki; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, 北海道支部講演会講演概要集, 2009, 48, 41, 42, 28 Nov. 2009
    The Japan Society of Mechanical Engineers, Japanese
  • 1401 Modification of effective viscosity in bubbly liquid due to bubble deformation
    SAKURAI Kousuke; OYAMA Kazuya; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, Fluids engineering conference ..., 2009, 427, 428, 06 Nov. 2009
    In order to obtain effective viscosity in bubbly liquid, which changes with transient bubble deformation, spatio-temporal velocity distributions of transient shear flows in a rotating cylinder is measured by using Ultrasonic Velocity Profiling (UVP) synchronizing of bubble deformation measurement. For Silicone oil of 1000 cSt as a test liquid, velocity distribution during spinning up has been found to be different from the liquid without bubbles. We have compared the circumferential acceleration of liquid with time serial images of bubble deformation to reach the conclusion that the maximal stretched bubbles the strongest drive the shear flow contrastively to the conventional equilibrium deformation theory of effective viscosity., The Japan Society of Mechanical Engineers, Japanese
  • 1804 Experimental investigation of flow over a standing baffle using UVP
    Jamshidnia Hamidreza; Tasaka Yuji; Murai Yuichi; Takeda Yasushi, Fluids engineering conference ..., 2009, 523, 524, 06 Nov. 2009
    Effect of an intermediate standing baffle on the flow structure in a rectangular open channel has been studied by using Ultrasonic Doppler Velocimetry (UVP). Distributions of time-averaged on-axis velocity profiles at different streamwise positions indicate the flow structure of the uprising flow at the upstream of baffle and specifically vortex shedding at the downstream of the baffle. Importantly, comparison of space-dependent power spectra of upstream and downstream sections of the baffle indicates the existence of some peak structures near the baffle's edge for downstream sections which are corresponding to the periodic nature of flow concentrated mainly near the baffle's edge in the spatio-temporal velocity distribution. Such peak structures could not be observed for the upstream sections. For downstream sections mainly the existence of peak values in the space distribution of two frequency modes near the baffle's edge could be confirmed which can be attributed to the vortex shedding., The Japan Society of Mechanical Engineers, English
  • 1802 Ultrasonic flow field measurement of a rotating flow accompanied
    TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi; IIMA Makoto, Fluids engineering conference ..., 2009, 519, 520, 06 Nov. 2009
    Temporally irregular switching of rotating free surface is investigated by means of ultrasonic velocity profiling, UVP. Two methods, Doppler method and echo method, are complementarily used to detect position of the free surface together with spatio-temporal velocity distribution. Horizontal cross section of the free surface shape is estimated from the obtained interface variation., The Japan Society of Mechanical Engineers, Japanese
  • A Towing-tank Experiment on Dynamics of Air Bubble Introducer for Drag Reduction of Ships : Flow Visualization of Air Entrainment and Bubble Formation by the Flow Past a Cylinder beneath a Free Surface
    KUMAGAI Ichiro; NAKAMURA Naoya; MURAI Yuichi; TASAKA Yuji; TAKEDA Yasushi, 可視化情報学会誌. Suppl. = Journal of the Visualization Society of Japan, 29, 2, 9, 10, 15 Oct. 2009
    Japanese
  • D101 Study on Hydrofoil Type Bubble Generator for Drag Reduction of Ship
    MURAI Yuichi; KUMAGAI Ichiro; TASAKA Yuji; TAKEDA Yasushi; TAKAHASHI Yoshiaki, National Symposium on Power and Energy Systems, 2009, 14, 95, 96, 28 Jun. 2009
    Installation of hydrofoils to ship wetted surface enables bubble generation to be realized with power consumption much lower than conventional bubble generators. With help of this principle, net effect of frictional drag reduction for ships can be improved. We have already obtained around 10% net power-saving efficiency for a cargo ferry throughout about a half year. The power-saving has a large potential to be improved more by considering multiphase fluid dynamics in terms of the hydrofoil-water-air triple interaction. In this paper, the basic principle of the bubble generation and the trial parametric studies implemented by numerical and experimental visualizations are reported., The Japan Society of Mechanical Engineers, Japanese
  • A116 水平配列時のサボニウス風車の相互干渉(垂直軸方向風車の展開・改善・普及,OS2 自然エネルギー)
    繁富 啓詞; 村井 祐一; 田坂 裕司; 武田 靖, 動力・エネルギー技術の最前線講演論文集 : シンポジウム, 2009, 14, 45, 46, 28 Jun. 2009
    Experiments were conducted to explore the effects of the mutual interaction between two widely spaced Savonius rotors within a wind tunnel. The number of revolution was investigated for two different velocity and conditions, being under small friction and high friction with revolution control. The optimum set of the parameter was found to be u= 4.0 m/s, (x, y) = (2.0D, 0.5D) with two rotors rotating in the same direction under small friction, and the number of revolution of them became 9.1% larger than that of the single rotor. In contrast, increase of revolution was not observed with u= 5.0 m/s under the condition of revolution control and high friction. This result shows that the mutual interference of two Savonius rotors depends on the relation between wake structure and tip speed ratio., 一般社団法人日本機械学会, Japanese
  • Nine-months Stay at The University of Manchester
    TASAKA Yuji, Japanese journal of multiphase flow, 23, 1, 88, 90, 15 Mar. 2009
    日本混相流学会, Japanese
  • Ultrasound Doppler Measurement of Bubbly Turbulent Boundary Layer Beneath Vessel
    MURAI Yuichi; TASAKA Yuji; TAKEDA Yasushi; OHTA Shoko; SHIGETOMI Akinari; HINATSU Munehiko, Japanese journal of multiphase flow, 23, 1, 21, 28, 15 Mar. 2009
    日本混相流学会, Japanese
  • Effects of surface tension on irregular surface switching of rotating fluids
    TASAKA Yuji; IIMA Makoto, 日本流体力学会年会講演論文集, 2009, 153, 153, 2009
    This study aims to clarify the influence of surface tension of the fluids on irregular surface switching, which is a temporally irregular change of the free surface shapes in rotating fluids. 1 cSt Silicone oil, whose kinematic viscosity is almost same with water and surface tension is roughly one forth of that, is used as the test fluid to highlight the influence of the surface tension. The surface of the rotating oil shows sloshing ahead of the surface switching instead of the intermittent deformation of the surface shape which was observed in water., 日本流体力学会, Japanese
  • Development of 2-D velocity field scanner by ultrasonic Doppler
    OHTA Shoko; MURAI Yuichi; TASAKA Yuji; TAKEDA Yasushi, 可視化情報学会誌. Suppl. = Journal of the Visualization Society of Japan, 28, 2, 95, 96, 15 Sep. 2008
    Japanese
  • Relationship between vortex structure and drag reduction in Bubbly Taylor-Couette flow
    YOSHIDA Koji; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, 可視化情報学会誌. Suppl. = Journal of the Visualization Society of Japan, 28, 2, 13, 14, 15 Sep. 2008
    Japanese
  • Multi-Layer PIV Measurement of Internally Heated Convection by Color Light Sheet
    TAKAHASHI Junpei; YANO Kanako; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi; YANAGISAWA Takatoshi; YAMAGISHI Yasuko, 可視化情報学会誌. Suppl. = Journal of the Visualization Society of Japan, 28, 2, 59, 60, 15 Sep. 2008
    Japanese
  • Frictional Drag Reduction Promoted by Intermittent Bubble Injection
    H.-J. PARK; Y.OISHI; Y.TASAKA; Y.MURAI; Y.TAKEDA, European Drag Reduction and Flow Control Meeting 2008 Book of Abstracts, 34, 35, Sep. 2008, [Peer-reviewed]
    English
  • 3-D Measurement of downburst by Color PIV
    KANDA Tetsushi; MURAI Yuichi; TASAKA Yuji; TAKEDA Yasushi, 可視化情報学会誌. Suppl., 28, 1, 17, 18, 01 Jul. 2008
    Japanese
  • Cross Sectional Particle Concentration of Laboratory Model Tornado
    YOSHIMOTO Takahiro; MURAI Yuichi; TASAKA Yuji; TAKEDA Yasushi, 可視化情報学会誌. Suppl., 28, 1, 413, 414, 01 Jul. 2008
    Japanese
  • D203 Development of 3-D Trajectory Measurement System for Birds using Stereoscopic Photography
    KANDA Tetsushi; MURAI Yuichi; TASAKA Yuji; TAKEDA Yasushi; TEZUKA Hideaki; MORI Michitsugu, National Symposium on Power and Energy Systems, 2008, 13, 405, 406, 18 Jun. 2008
    The present study aims at developing a 3-D trajectory measurement system for birds (in particular endangered species, e.g. raptorial) flying around wind turbines as a part of its complete system to be applied for prevention from bird strike. The method is based on stereoscopic photography which is similar to 3-D particle tracking velocimetry. For stabilizing the bird-image detection performance, time differential technique is proposed and examined considering the influences of hour and weather. All tests are conducted at Hokkaido University firm. For the demonstration purpose, 3-D trajectories of crows above the firm are obtained and shown in order to assess the effectiveness of stereoscopic photography., The Japan Society of Mechanical Engineers, Japanese
  • E111 Ultrasonic Doppler Measurement of Bubble-Containing Turbulent Boundary Layer Beneath a Large Ship
    OHTA Shoko; SHIGETOMI Akinari; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi; HINATSU Munehiko; KODAMA Yoshiaki, National Symposium on Power and Energy Systems, 2008, 13, 227, 228, 18 Jun. 2008
    Friction drag accounts for 80 % of the total drag for large ships, and hence microbubble drag reduction is expected as one of the most feasible ways to reduce it because of less environmental impact. The demonstration experiment using 127m-ship is carried out and its turbulent boundary layer is measured by UVP for the first time. This report mainly describes the measurement method of seawater velocity profiles beneath the ship and some typical results on the influences of bubbles on their statistic values., The Japan Society of Mechanical Engineers, Japanese
  • 回転流れにおける表面大変形の遷移および分岐 (乱流研究の展望 : ブレークスルーを求めて)
    飯間 信; 田坂 裕司; 伊藤 賢太郎, 数理解析研究所講究録, 1601, 80, 85, Jun. 2008
    京都大学, Japanese
  • Oscillating Taylor-Couette Flow (Azimuthal motion)
    Yasushi Takeda; Masato Morinaga; Yuji Tasaka, 15TH INTERNATIONAL COUETTE-TAYLOR WORKSHOP, 137, 012002, 2008, [Peer-reviewed]
    English
  • The behaviour of Couette-Taylor flow in an azimuthal plane
    Yuuta Nomura; Yuji Tasaka; Yuichi Murai; Yasushi Takeda, 15TH INTERNATIONAL COUETTE-TAYLOR WORKSHOP, 137, 012001, 2008, [Peer-reviewed]
    English
  • Rotating flow transition related to surface switching
    Yuji Tasaka; Makoto Iima; Kentaro Ito, 15TH INTERNATIONAL COUETTE-TAYLOR WORKSHOP, 137, 3, 163, 172, 2008, [Peer-reviewed]
    English
  • Experimental study of convection cell structure in internally heated layer
    TAKAHASHI Junpei; YANO Kanako; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi; YANAGISAWA Takatoshi; YAMAGISHI Yasuko, 日本流体力学会年会講演論文集, 2008, 61, 61, 2008
    Transition mechanisms of convection cell induced by internal heat sources in a shallow fluid layer are investigated experimentally. We attempt to determine the flow structure in a cell by Particle Image Velocimetry (PIV). Simultaneous multi-layer measurement is performed by color-striped light sheet and transitional state of convection cell is investigated. Vertical velocity component is also obtained and we investigate how cell behaves with respect of R_1 quantitatively. We confirmed cell transition is strongly related with development of descending flow at the center of a cell. Cell dilatation process is described as a consequence descending flow develops and strongly expands at the bottom of the fluid layer., 日本流体力学会, Japanese
  • 50m模型船における船底境界層のUVP計測(所外発表論文等概要)
    太田 翔子; 田坂 裕司; 村井 祐一; 武田 靖; 日夏 宗彦; 児玉 良明, 海上技術安全研究所報告, 8, 2, 224, 224, 2008
    海上技術安全研究所, Japanese
  • Interaction Between Streamwise Vortex and Bubbles in Horizontal Channel Flow
    T.SUZUKI; Y.OISHI; Y.MURAI; Y.TASAKA; Y.TAKEDA, Proc. 13th International Symposium on Flow Visualization, 2008, [Peer-reviewed]
    English
  • 自由表面大変形を伴う円筒容器内の回転流れの実験および数理的解析
    飯間 信; 田坂 裕司; 佐藤 讓; 眞山 博幸, 日本流体力学会年会2008講演論文集, 2008
    Japanese
  • 102 Relationship between drag reduction and microbubble motion in concentric rotating cylinders(2)
    YOSHIDA Koji; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, Fluids engineering conference ..., 2007, "102, 1"-"102-4", 17 Nov. 2007
    Relationship between drag reduction and microbubble motion in a vertical Taylor-Couette flow is investigated by visualization of r-z cross section. We have measured the vorticity distribution in two-phase condition by means of particle tracking velocimetry (PTV). The bubble distribution shows two modes as Re number changes, i.e. toroidal and spiral modes. In low Re number region, the vortex structure is modified significantly by the bubbles. The presence of bubbles provides elongation of vortical wavelength to be around 1.5 times as that without bubbles. This alternation of the cell yields a large reduction ratio of the shear stress in low Re number region while the drag reduction effect is weakened as Re number increases for the high kinetic energy of the cell motion., The Japan Society of Mechanical Engineers, Japanese
  • 911 Ultrasonic measurement of boundary layer bubble distribution for microbubble drag reduction(2)
    OHTA Shoko; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi; HINATU Munehiko; KODAMA Yoshiaki, Fluids engineering conference ..., 2007, "911, 1"-"911-4", 17 Nov. 2007
    Friction drag accounts for 80 % of the total drag for large ships, and hence microbubble drag reduction is expected as one of the most feasible ways to reduce it because of less environmental impact and easy installation. The basic experiment to confirm the drag reduction effect was performed from 1970's, and it comes to the stage of a practical examination for moving ships. As a method to assess the bubble-originated alternation of the boundary layer structure beneath a moving ship, we have designed a ship-mounting type of ultrasound probe to apply ultrasound velocity profiler (UVP) and examined the measurement performance for a long towing-ship in NMRI 400m-run facility. The probe emits 2MHz-pulsed ultrasound at 75 degree to the main flow direction to acquire the turbulent velocity profile up to 7.2m/s in the fastest case. This report mainly describes the measurement method of bubble distribution in the boundary layer. The method is constructed by the probability theory of ultrasound reflection on individual bubbles, and examined by numerical simulation. This application to a 50m-model ship reveals that the water flow boundary layer changes to steep profile where the bubbles are concentrated., The Japan Society of Mechanical Engineers, Japanese
  • 912 Development of a multiphase flowmeter by means of Ultrasonic Velocity Profiling(2)
    Gonzalez A. S. Roberta; Tasaka Yuji; Murai Yuichi; Takeda Yasushi, Fluids engineering conference ..., 2007, "912, 1"-"912-4", 17 Nov. 2007
    In this paper the liquid phase velocity and gas-liquid interface information obtained from UVP measurements are used to estimate the flowrate in a multiphase flow pipeline. The interface is found two different approaches ; by locating the maximum echo intensity at every velocity profile and by finding the maximum variance of the velocity values. The results from the echo intensity method show very good agreement with the actual flowrate. The expected average difference between the flowrate predicted by the echo intensity method and the actual flowrate is ± 5%. That between the variance of the velocity values method and the actual flowrate is -19 to 22 %., The Japan Society of Mechanical Engineers, English
  • 308 Wake of a permeable circular cylinder(2)
    TAKEUCHI Hirotaka; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, Fluids engineering conference ..., 2007, "308, 1"-"308-4", 17 Nov. 2007
    Particle image velocimetry (PIV) is applied to measurement of airflows around permeable circular cylinders. The aim of this study is to understand the wake structure of a permeable object subjected to uniform flow, such as buildings under construction, steel tower frames, and natural trees. The experimental model of the permeable cylinder is made of squared meshed sheet with a mesh number 32 and an opening ratio of 0.54. The following points are newly found when the flow field is compared to that of a solid cylinder. 1: In case of the permeable cylinder, the turbulence peak appears in a downstream region relative to the solid cylinder, because generation of vortex street is delayed significantly. 2: The drag is not simply estimated only by the opening ratio of the permeable cylinder. 3: The permeable cylinder has non-periodical vortex shedding. This has been confirmed from the correlation coefficient between the enstrophy and the turbulence intensity, which is greater than the solid one., The Japan Society of Mechanical Engineers, Japanese
  • 308 Investigation of Magnetic Permeability and Effective-kinematic Viscosity of Liquid Metal in Uniform Magnetic Field
    YANO Kanako; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi; Patrice Le Gal, 北海道支部講演会講演概要集, 2007, 46, 83, 84, 29 Sep. 2007
    The Japan Society of Mechanical Engineers, English
  • 307 Extraction of a pitching component of a ship from spatio-temporal velocity distribution
    TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, 北海道支部講演会講演概要集, 2007, 46, 81, 82, 29 Sep. 2007
    The Japan Society of Mechanical Engineers, Japanese
  • 309 Measurement of Velocity Distribution in a Cell of Internally Heated Convection
    TAKAHASHI Junpei; YANO Kanako; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, 北海道支部講演会講演概要集, 2007, 46, 85, 86, 29 Sep. 2007
    The Japan Society of Mechanical Engineers, Japanese
  • 円筒容器内における表面大変形を伴う回転流れの実験的研究(乱流と輸送現象:コーヒーカップから宇宙まで)
    飯間 信; 伊藤 賢太郎; 田坂 裕司, 数理解析研究所講究録, 1567, 132, 140, Aug. 2007
    京都大学, Japanese
  • Motion of Microbubbles Relative to Streamwise Vortices in the Wall Turbulence
    Y.OISHI; Y.MURAI; Y.TASAKA; Y.TAKEDA, Abstracts of the6th International Conference on Multiphase Flow, S1_Wed_C_37, CD-ROM 55, Aug. 2007, [Peer-reviewed]
    English
  • Thermal convection in liquid gallium layer with uniform magnetic field
    TASAKA Yuji; YANO Kanako; MURAI Yuichi; TAKEDA Yasushi; YANAGISAWA Takatoshi, 日本流体力学会年会講演論文集, 2007, 168, 168, 2007
    This study aims to clarify the mechanism of an oscillating motion of the convection cell appearing in the thermal convection of a liquid gallium layer. Ultrasonic Velocity Profiling (UVP) was employed to visualize and quantitativelly estimate the fluid motion of the convection. Obtained spatio-temporal velcocity distributions well represent the convective motion including the oscillating motion of the cell. A result of a numerical simulation, which was done in the same condition with the experiment, and experimental estimation of the Reynolds number mension that the oscillating motion may be induced by instability of separated thermal boundary layers. Thermal convection in uniform magnetic field was also investigated by means of UVP. The obtained spatio-temporal velocity distribution showed us a two dimensionalization of the convective motion as influence of the applying magnetic field., 日本流体力学会, Japanese
  • Experimental and theoretical analysis on the rotating fluid with large surface deformation in a cylinder
    Ito Kentaro; Iima Makoto; Tasaka Yuji, 日本流体力学会年会講演論文集, 2007, 153, 153, 2007
    We analyzed the temporal variation of the surface shape of water in an open cylinder driven by constant rotation of the bottom. In a range of Reynolds number, the surface deformation of the order of the container size shows an aperiodic switching between an axisymmetric surface shape and a nonaxisymmetric surface shape. Time-series analysis of the surface height clarify the characteristics of the flow also switches between laminar and turbulent during the switching process. We also analyzed the variation of turbulent intensity with respect to Raynolds number with a different setup using different material. It is found that the transition Reynolds number is shifted significantly, and that the surface shape shows an intermittent destabilization preceding to the transition. To understand the effect of the material difference, we derived an equation which describes the dynamics of the free surface near the bottom by using a thin-film theory., 日本流体力学会, Japanese
  • Experimental investigation for onset of modulated wave in Taylor-Couette flow
    NOMURA Yuuta; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, 日本流体力学会年会講演論文集, 2007, 164, 164, 2007
    We investigated azimuthal behaviors of Taylor-Couette flow on the azimuthal cross section by flow visualization using Kalliroscope flakes, and by image analysis of the obtained movie. Kalliroscope flakes are platelet and can make shear flow visible. Wavy vortex flow mode (WVF) in which an azimuthal wave mode superposes Taylor vortex flow mode (TVF) was investigated. Wave number and phase velocity of the azimuthal wave appearing in WVF at higher Reynolds number were determined by image analysis. Azimuthal flow structure of modulated wavy vortex flow mode (MWVF) was clearly visualized and the modulation component of MWVF was investigated by Fourier analysis of a temporal variation of brightness distribution extracted from a movie of visualized flow. Continuous wavelet analysis indicates that the modulation might occur for all wave regions but with different characteristics., 日本流体力学会, Japanese
  • Ultrasonic measurement of instantaneous velocity vector profile
    Yasushi Takeda; Yuji Tasaka, FEDSM 2007: PROCEEDINGS OF THE 5TH JOINT AMSE/JSME FLUIDS ENGINEERING SUMMER CONFERENCE VOL 1, PTS A AND B, 701, 706, 2007, [Peer-reviewed]
    English
  • Dynamics and optics of bubble tracking velocimetry for airflow measurement
    Tetsushi Kanda; Yuji Tasaka; Yuichi Murai; Yasushi Takeda, FEDSM 2007: PROCEEDINGS OF THE 5TH JOINT AMSE/JSME FLUIDS ENGINEERING SUMMER CONFERENCE VOL 1, PTS A AND B, 679, 686, 2007, [Peer-reviewed]
    English
  • Environmental flow field measurement by ultrasonic velocity pofiling
    Yuji Tasaka; Yasushi Takeda; Kaoru Yokoyama; Shinya Kojima, FEDSM 2007: PROCEEDINGS OF THE 5TH JOINT ASME/JSME FLUIDS ENGINEERING SUMMER CONFERENCE, VOL 2, PTS A AND B, 1237, 1244, 2007, [Peer-reviewed]
    English
  • Alternation of a Pair of Streamwise Vortex by Bubbles
    T.SUZUKI; Y.OISHI; Y.MURAI; Y.TASAKA; Y.TAKEDA, Bulletin of 60th Annual Meeting of the Division of Fluid Dynamics, American Physical Society, 52, 17, 136, 2007, [Peer-reviewed]
    English
  • Particle image velocimetry for air flows behind permeable cylinders
    Hirotaka Takeuchi; Yuichi Murai; Yuji Tasaka; Yasushi Takeda; Hideaki Tezuka; Michitsugu Mori, FEDSM 2007: PROCEEDINGS OF THE 5TH JOINT AMSE/JSME FLUIDS ENGINEERING SUMMER CONFERENCE VOL 1, PTS A AND B, 671, 678, 2007
    English
  • A244 Ultrasonic Detection of Water Distribution in Gas Diffusion Layer of Fuel Cell
    Kondoh Takayuki; Tasaka Yuji; Murai Yuichi; Takeda Yasushi, Procee[d]ings of Thermal Engineering Conference, 2006, 251, 252, 23 Nov. 2006
    Thermal efficiency of polymer electrolyte fuel cell extremely depends on a water distribution in Gas Diffusion Layer (GDL). Fuel cell model was prepared in order to investigate the water distribution in GDL by ultrasonic techniques. Acoustic impedance of GDL, which is porous plate of carbon, was estimated as bulk model to know approximated value of reflection ratio of ultrasonic echo. We attempted to measure an instantaneous ultrasonic echo that changes by the quantity of the water to detect existing water in GDL. And we focused on the phase delay and the amplitude change of the ultrasonic echo and analyzed the waveform., The Japan Society of Mechanical Engineers, Japanese
  • A243 Velocity Profiling of Ship Surface Flow with Ultrasonic Doppler Method
    Murai Yuichi; Tasaka Yuji; Ohta Shoko; Takeda Yasushi, Procee[d]ings of Thermal Engineering Conference, 2006, 249, 250, 23 Nov. 2006
    Ultrasonic velocity profiler (UVP) is applied to measurement of water flow under the bottom surface of a ship. The aim of this study is to establish the practical utilization of UVP system for large ships whose power loss is generally dominated by frictional drag. As the first phase, the measurement performance is evaluated for capturing the turbulent boundary layer of a small model ship using a new ultrasonic transducer. The experiments are performed for a towing ship in a shallow pond and also for a freely supported ship in an open channel. A wedge type of ultrasonic transducer is designed so that the flow is undisturbed with it. The velocity profile including the boundary layer is successfully obtained after suitable post-processing is implemented to remove erroneous data caused by multiple reflections. Data analysis is also made to estimate the skin friction from the profiles measured., The Japan Society of Mechanical Engineers, Japanese
  • 超音波流速分布計を用いた液体金属の流動計測--液体金属の複雑な流動を捉える
    田坂 裕司; 武田 靖; 大林 寛生, 超音波techno, 18, 6, 70, 74,120, Nov. 2006
    日本工業出版, Japanese
  • Stereoscopic Particle Tracking Velocimetry Applied to Fireworks
    M.MORINAGA; Y.OISHI; Y.TASAKA; Y.MURAI; Y.TAKEDA, APS Gallery of Fluid Motion Poster Session, Nov. 2006, [Peer-reviewed]
    English
  • 1103 Hysteretic Mode Exchange in the Wake of Two-Tandem Cylinders(1)
    TASAKA Yuji; KON Seiji; LE GAL Patrice, Fluids engineering conference ..., 2006, "1103, a", 28 Oct. 2006
    図1に示すような,流れに対して直列に配置された2円柱の後流では,低レイノルズ数において,間隙比Γ=l/dに依存して2つの異なる流れのモードが現れる.すなわち,2円柱間の流線が閉じ,それらがあたかも一つの楕円柱であるかのように,そのサイズの流れの変動が生じるモード(Slow mode),および上流円柱後流の対称性が崩れ,円柱スケールの変動が生じるモード(Fast mode)である.本研究では,Mizushima & Suehiroによる数値シミュレーションと線形安定性解析により示されたヒステリシス的なモード変化を実験的に検証するとともに,円柱が有限長さを持つことにより生じる3次元効果の影響について述べる., The Japan Society of Mechanical Engineers, Japanese
  • 1708 Velocity Vector Profile Measurement using Multiple Ultrasound Transducers(2)
    Kon Seiji; Yamaguchi Kouhei; Obayashi Hironari; Tasaka Yuji; Murai Yuichi; Takeda Yasushi, Fluids engineering conference ..., 2006, "1708, 1"-"1708-4", 28 Oct. 2006
    Unit of Vector-UVP system, which is an advanced UVP system to measure three directional velocity components on a line by using multiple transducers, was developed. To optimize the Vector-UVP system, we attempted to determine an acoustic field generated by a focusing transducer, which can focuses ultrasound via acoustic lens mounted at the head of the transducer. The acoustic intensity was measured using a small hydrophone by scanning the sound field. It is also theoretically calculated by solving two-dimensional wave equation to validate the measured results, such as focal point of the ultrasonic beam. We also estimated the influence of an intermediate wall existing between target fluid and the transducer on the acoustic field. With the estimated results, the measurement volume and the measurement area were determined so that the system is optimized. The system was applied to the measurement of two directional velocity components of Karmann vortices in a wake of a circular cylinder to demonstrate the applicability to multi-dimensional unsteady flow. From the measured velocity vector profile, the two-dimensional vorticity distribution were validly detected using the present vector-UVP system after Taylor's frozen hypothesis was considered., The Japan Society of Mechanical Engineers, Japanese
  • 1705 UVP Measurement for Flows Accompanying Free Surface(2)
    KOJIMA Shinya; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, Fluids engineering conference ..., 2006, "1705, 1"-"1705-4", 28 Oct. 2006
    The discharge of the overflow at a dam is currently determined by applying an empirical equation estimated on ideal system to water level at the dam. However the real overflow on large scale has many uncertain factors and thus the estimated discharge has large errors, which may be order of several ten percent. Until now, we have studied an overflow measurement by using ultrasonic velocity profiler (UVP) to realize more accurate measurement of the discharge (Kashiwaguma, 2003). Cross-sectional velocity distribution over the weir setting in an open channel was measured by UVP and discharge calculated from velocity distribution was compared with discharge determined from the empirical equation. That system has slightly error because of rough detecting the position of free surface on measurement line. To reduce error in the measurement of the discharge, we must acquire the position exactly. In this study, we attempted to utilize the amplitude information of US echo which has not been used to calculate the velocity profile in conventional UVP. The velocity profile was measured in the vertical direction on the condition accompanying free surface in an open channel. The time evolution of the free surface displacement was measured by using the amplitude information of reflected ultrasound at the surface. The measured position was compared with an alternative measurement method based on the position meter fixed on the measurement line of UVP and then the accuracy of the present method was verified., The Japan Society of Mechanical Engineers, Japanese
  • 1705 UVP Measurement for Flows Accompanying Free Surface(1)
    KOJIMA Shinya; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, Fluids engineering conference ..., 2006, "1705, a", 28 Oct. 2006
    The Japan Society of Mechanical Engineers, Japanese
  • 1708 Velocity Vector Profile Measurement using Multiple Ultrasound Transducers(1)
    Kon Seiji; Yamaguchi Kouhei; Obayashi Hironari; Tasaka Yuji; Murai Yuichi; Takeda Yasushi, Fluids engineering conference ..., 2006, "1708, a", 28 Oct. 2006
    The Japan Society of Mechanical Engineers, Japanese
  • 1711 UVP measurement of gas-liquid two phase flow in a horizontal tube(2)
    Ohashi Junichi; Tasaka Yuji; Murai Yuichi; Takeda Yasushi, Fluids engineering conference ..., 2006, "1711, 1"-"1711-4", 28 Oct. 2006
    As a basic study for developing a two-phase flowmeter by means of ultrasonic velocity profiler(UVP), theoretical and numerical estimations of the phase distribution measurement are performed. The measurement accuracy depends on the number of ultrasonic measurement lines. When the azimuthal resolution is lacked, the error grows up for low void fraction conditions. Considering the relative resolution to radial direction, the sufficient number of the lines is concluded as 8. A practical measurement for a slug flow is also carried out to understand the internal secondary flow that affects on the flow rate measured by UVP., The Japan Society of Mechanical Engineers, Japanese
  • 708 Wall Turbulence Containing Bubbles Visualized by Kalliroscope(2)
    OISHI Yoshihiko; MURAI Yuichi; LATRACHE Noureddine; TASAKA Yuji; TAKEDA Yasushi, Fluids engineering conference ..., 2006, "708, 1"-"708-4", 28 Oct. 2006
    Flow visualization of the turbulent structure in a bubbly channel flow is performed at Re=1333. Kalliroscope is used as the tracer, which is a dispersion of flake-like micros-scale particles with high optical reflection. The optical characteristic of the particle is analyzed by numerical simulation to confirm that the more the reflection intensity increases, the more the shear increases. The results of the application to actual visualization reveal the structures of the streamwise vortices and the low-speed streaks. When the micro bubbles are injected in the channel, the turbulent structure changes to a macular state, i.e. the original longitudinal structure is shortened by the bubbles., The Japan Society of Mechanical Engineers, Japanese
  • 513 Environmental Flow Measurement using Ultrasonic Velocity Profiler
    TASAKA Yuji; KOJIMA Shinya; YOKOYAMA Kaoru; MURAI Yuichi; TAKEDA Yasushi, 北海道支部講演会講演概要集, 2006, 45, 179, 180, 25 Sep. 2006
    The Japan Society of Mechanical Engineers, Japanese
  • 202 Development of smoke generator for airflow PIV measurement
    TAKEUCHI Hirotaka; TASAKA Yuji; OISHI Yoshihiko; MURAI Yuichi; TAKEDA Yasushi; TEZUKA Hideaki; MORI Michitsugu, 北海道支部講演会講演概要集, 2006, 45, 43, 44, 25 Sep. 2006
    The Japan Society of Mechanical Engineers, Japanese
  • 215 Development of Color PIV Systtem for 3-D Airflow Measurement
    MURAI Yuichi; TASAKA Yuji; TAKEDA Yasushi, 北海道支部講演会講演概要集, 2006, 45, 69, 70, 25 Sep. 2006
    The Japan Society of Mechanical Engineers, Japanese
  • 214 Ultrasonic measurement of velocity profile near the bottom of a ship
    OHTA Shoko; KONDOH Takayuki; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, 北海道支部講演会講演概要集, 2006, 45, 67, 68, 25 Sep. 2006
    The Japan Society of Mechanical Engineers, Japanese
  • 23pXG-14 Transition of free-surface in rotating flow
    Ito Kentaro; Iima Makoto; Tasaka Yuji, Meeting abstracts of the Physical Society of Japan, 61, 2, 187, 187, 18 Aug. 2006
    The Physical Society of Japan (JPS), Japanese
  • UVP and PTV Measurements of Wall Boundary Layer Containing Bubbles
    MURAI Yuchi; FUJII Hideki; MATSUBARA Yoshiaki; OISHI Yoshihiko; TASAKA Yuji; TAKEDA Yasushi, 可視化情報学会誌. Suppl., 26, 1, 315, 316, 01 Jul. 2006
    Japanese
  • Visualization of vortex rings with background rotation
    OISHI Yoshihiko; MORINAGA Masato; MURAI Yuichi; TASAKA Yuji; TAKEDA Yasushi; THOMAS Peter J., 可視化情報学会誌. Suppl., 26, 1, 333, 334, 01 Jul. 2006
    Japanese
  • Ultrasonic Visualization of Fluid Flow of Liquid Metal
    TASAKA Yuji; YANAGISAWA Takatoshi; MURAI Yuichi; TAKEDA Yasushi, 可視化情報学会誌. Suppl., 26, 1, 353, 354, 01 Jul. 2006
    Japanese
  • Particle Tracking Velocimetry for a Large Flow Phenomenon Demonstrated by Fireworks
    MORINAGA Masato; OISHI Yoshihiko; MURAI Yuichi; TASAKA Yuji; TAKEDA Yasushi, 可視化情報学会誌. Suppl., 26, 1, 289, 290, 01 Jul. 2006
    Japanese
  • Waveforms of Local Frictional Drag Modified by Bubbles
    Y.OISHI; Y.MURAI; Y.TASAKA; Y.TAKEDA; Y.KODAMA, Proc. European Drag Reduction and Flow Control Meeting, 25, 26, Apr. 2006, [Peer-reviewed]
    English
  • AM06-14-001 Experimental study of thermal convection in liquid metal layer
    TASAKA Yuji; YOSHIDA Masataka; MURAI Yuichi; TAKEDA Yasushi; YANAGISAWA Takatoshi, 日本流体力学会年会講演論文集, 2006, 177, 177, 2006
    Thermal convection in liquid gallium layer is investigated as a fundamental study for Rayleigh-Benard convection in low Prandtl number fluid using ultrasonic velocity profiler, UVP. Measured velocity profiles visualize a convective motion in the liquid gallium layer, and it is a roll shape motion. Spatio-temporal velocity profile shows that there are two types of spatial fluctuation of the convection roll. Two axes-simultaneous velocity profile measurement clarifies that expand and contraction of convection roll has a phase delay on the direction of the rotating axis of the roll. Frequency analysis of the obtained instantaneous velocity distribution shows that the convective motion has unique frequency component of the velocity fluctuation at the boundaries between the rolls. The frequency component cannot be detected at smaller Rayleigh number, under R=1×10^4. The frequency is proportional to the Rayeigh number to the power 0.376., 日本流体力学会, Japanese
  • AM06-11-003 Interfacial instability of rotating liquid-liquid two phase flow
    FUJIMOTO Shuhei; TASAKA Yuji; TAKEDA Yasushi; YOSHIDA Shizuo, 日本流体力学会年会講演論文集, 2006, 129, 129, 2006
    The aim of this study is to find out an instability mechanism of rotating oil-water liquid-liquid two phase flow. To achieve such purpose, a velocity profile of the rotating flow was analyzed theoretically. The theoretical velocity profile was in agreement with a experimental result., 日本流体力学会, Japanese
  • AM06-11-004 Relation between surface switching of rotating flow in a cylinder and the laminar-turbulent transition
    Iima Makoto; Tasaka Yuji; Ito Kentaro, 日本流体力学会年会講演論文集, 2006, 130, 130, 2006
    We study the surface shape of water in an open cylinder driven by constant rotation of the bottom. Around the critical Reynolds number for the laminar-turbulent transition, the surface deformation, which is of the order of the container size, shows an aperiodic switching phenomenon between an axisymmetric shape and a nonaxisymmetric shape. The flow characteristics is examined by flow visualization by Kalliroscope and velocity measurement by ultrasonic velocity profiler., 日本流体力学会, Japanese
  • AM06-11-002 Energy dissipation in wavy motion of oscillating Taylor-Couette flow
    Morinaga Masato; Tasaka Yuji; Takeda Yasushi; Murai Yuichi, 日本流体力学会年会講演論文集, 2006, 128, 128, 2006
    We attempted a direct energy injection to a higher flow mode of Taylor-Couette flow by using modulated rotation of an inner cylinder. Wavy vortex flow (WVF) mode was chosen as target of the energy injection and then a characteristic frequency of WVF is set to a basic frequency of the modulated rotation. Ultrasonic velocity profiler (UVP) measured an instantaneous velocity profile of the flow under the modulated rotation, and influence of the modulation in the flow was investigated. The measurement of instantaneous velocity profile of axial and radial component of flow velocity showed that this method cannot increase energy of WVF mode but can change shape of spectrum sharp at frequency of wavy motion in WVF., 日本流体力学会, Japanese
  • AM06-11-001 Experimental investigation on azimuthal motion of Taylor-Couette flow
    NOMURA Yuuta; MORINAGA Masato; TASAKA Yuji; MURAI Yuichi; TAKEDA Yasushi, 日本流体力学会年会講演論文集, 2006, 127, 127, 2006
    We attempted to investigate flow structures of Taylor-Couette Flow (TCF) at the azimuthal cross section by flow visualization using Kalliroscope flakes, which is platelet and can make share flow visible, and by image processing of the obtained image. It is confirmed that the established measurement technique can reproduce structure of the Taylor vortex. This technique is also applied to determine wavenumber and phase velocity of the azimuthal wave appearing in wavy vortex flow (WVF) mode at higher Reynolds number. Moreover, azimuthal flow structure of modulated wavy vortex flow (MWV) is clearly visualized and modulation component of MWV is detected by the image processing, which is Fourier analysis of temporal variation of brightness profile extracted from a movie of visualized flow., 日本流体力学会, Japanese
  • 1015 PTV Measurement of natural convection driven by internal heating of fluids
    Murai Yuichi; Tasaka Yuji; Takeda Yasushi, Fluids engineering conference ..., 2005, 155, 155, 28 Oct. 2005
    The Japan Society of Mechanical Engineers, Japanese
  • 1104 Ultrasonic Measurement for Taylor-Couette Flow of Liquid Gallium
    KONDOH Takayuki; SATOH Yohei; TASAKA Yuji; TAKEDA Yasushi, Fluids engineering conference ..., 2005, 160, 160, 28 Oct. 2005
    The Japan Society of Mechanical Engineers, Japanese
  • 505 Investigation on cross-sectional structure of gas-liquid two-phase pipe flows using backlight CT
    Inaba Kazumasa; Ohashi Jyunichi; Tasaka Yuji; Murai Yuichi; Takeda Yasushi, Fluids engineering conference ..., 2005, 65, 65, 28 Oct. 2005
    The Japan Society of Mechanical Engineers, Japanese
  • 212 UVP Measurement of Phase Distribution and Velocity Profile in a Horizontal Gas-Liquid Two-phase Channel
    藤井 秀基; 大石 義彦; 田坂 裕司; 村井 祐一; 武田 靖, 北海道支部講演会講演概要集, 2005, 44, 62, 63, 08 Oct. 2005
    The Japan Society of Mechanical Engineers, Japanese
  • Pattern formation in natural convection induced by internal heat generation
    TASAKA Yuji; TAKEDA Yasushi, 形の科学会誌 = Bulletin of the Society for Science on Form, 20, 1, 73, 74, 01 Jun. 2005
    Japanese
  • Visualization of Horizontal Wall Turbulence Containing Bubbles
    MURAI Yuichi; FUJII Hideki; NISHIMOTO Masahiro; TASAKA Yuji; TAKEDA Yasushi, 可視化情報学会誌. Suppl., 25, 1, 31, 32, 15 Mar. 2005
    Japanese
  • Experimental investigation of natural convection induced by internal heat generation
    Y. Tasaka; Y. Kudoh; Y. Takeda; T. Yanagisawa, 14TH INTERNATIONAL COUETTE TAYLOR WORKSHOP, 14, 168, 179, 2005, [Peer-reviewed]
    English
  • Measurement of Liquid Gullium by Ultrasonic Doppler Velocity Profiler
    Tasaka Yuji; Kitaura Hidekazu; Yoshida Masataka; Takeda Yasushi; Yanagisawa Takatoshi, Fluids engineering conference ..., 2004, 313, 313, 24 Nov. 2004
    The Japan Society of Mechanical Engineers, Japanese
  • E131 Analysis of a temperature field in internally heated convection :
    TASAKA Yuji; KUDO Yoichi; TAKEDA Yasushi; YANAGISAWA Takatoshi, 日本流体力学会年会講演論文集, 2004, 154, 155, 2004
    Thermal convection in a horizontal fluid layer induced by internal heat generation is investigated experimentally. Thermo-chromic Liquid Crystal (TLC) is used to visualize the temperature field in the fluid layer. Color component of TLC is calibrated and the visualized image is converted to the temperature field. Temperature field for each Rayleigh number determines the convection cell dilatation with respect to the Rayleigh number. Deformation of the cell with increasing the Rayleigh number is shown by the temperature profile in a cell. The critical Rayleigh number at onset of convection is estimated by using a variation of temperature difference in a cell., 日本流体力学会, English
  • Sound Speed Measurement of PCM Micro Emulsion Slurry
    Didier Vuarnoz; Tasaka Yuji; Takeda Yasushi; Inaba Hideo, Fluids engineering conference ..., 2003, 36, 36, 18 Sep. 2003
    The Japan Society of Mechanical Engineers, English
  • A new algorithm for low velocity measurement by UVP
    TADATA Norihiko; TAKEDA Yasushi; TASAKA Yuji, Fluids engineering conference ..., 2003, 33, 33, 18 Sep. 2003
    The Japan Society of Mechanical Engineers, Japanese
  • Spatiotemporal behavior of the precessing jet
    KITAURA Hidekazu; SUGAWARA Yuuki; TASAKA Yuji; TAKEDA Yasushi, 日本流体力学会年会講演論文集, 2003, 416, 417, 2003
    A continuously unstable precessing flow is formed within a short cylindrical chamber following a large sudden expansion and the jet emerges from nozzle exit leaning and rotating about the nozzle axis. Flow field within the nozzle chamber and the behavior of the external jet have been reported with pressure measurement, visualization and so on. This paper shows characteristics of the precessing jet, a frequency of rotating about the nozzle axis and an angle of emerging jet, using UDM (Ultrasound Doppler Method) which can measure 1-D velocity distribution on a measurement line instantaneously., 日本流体力学会, Japanese
  • Stability of Natural Convection in a Horizontal Layer induced by Internal Heating : Effect of Distribution of Heat Generation
    TASAKA Yuji; TAKEDA Yasushi, 日本流体力学会年会講演論文集, 2003, 382, 383, 2003
    A natural convection in a horizontal fluid layer induced by internal heat generation distributed non-uniformly was studied. We considered the heat source distribution to vary exponentially to the vertical direction. Stability of the fluid layer was analyzed in cases that heat source concentrates on the bottom, and on the upper boundary. Variations of critical values, critical Rayleigh number and critical wave number, with respect to the specific scale of the heat source distribution were obtained. The analysis clarified the effects of such heat source distributions on the critical values of the natural convection., 日本流体力学会, Japanese
  • Experiment on natural convection in a horizontal layer induced by internal heat generation
    KUDOH Yohichi; TASAKA Yuji; YONEKURA Kengo; TAKEDA Yasushi, 日本流体力学会年会講演論文集, 2003, 384, 385, 2003
    Natural convection induced by intemal heat generation was studied experimentally. We realized internal heat generation by passing electric current through the ionic fluid. The convective flow pattems were visualized by using Kalliroscope. And also the difference from those observed in the Benard configuration was clarified qualitatively., 日本流体力学会, Japanese
  • Natural Convection in the Horizontal Fluid Layer driven by Internal Heat Generation : 2. Flow Visualization
    YONEKURA Kengo; TASAKA Yuji; KUDO Yoichi; TADATA Norihiko; TAKEDA Yasushi; ISHIKAWA Hitoshi, 北海道支部講演会講演概要集, 2002, 42, 38, 39, 05 Oct. 2002
    The natural convection induced by internal heat generation was studied experimentally. We realized internal heat generation by passing electric current through the ionic fluid. The convective flow patterns were visualized by using kalliroscope. And also the difference from those observed in the Benard configuration was clarified qualitatively., The Japan Society of Mechanical Engineers, Japanese
  • Natural Convection in the Horizontal Fluid Layer driven by Internal Heat Generation : 1. Stability Analysis
    TASAKA Yuji; YONEKURA Kengo; KUDO Yoichi; TADATA Norihiko; TAKEDA Yasushi; ISHIKAWA Hitoshi, 北海道支部講演会講演概要集, 2002, 42, 36, 37, 05 Oct. 2002
    The natural convection induced by internal heating was studied. In order to clarify convective patterns in this phenomenon, we analyzed stability of fluid layers for various profiles of heat generation, H(z). As the result, the influence of the shape of the heat distribution upon the convective pattern was clarified., The Japan Society of Mechanical Engineers, Japanese
■ Books and other publications
  • 理科総合大百科 2024: ためしてわかる 実験・観察
    『理科教育ニュース』編集部, p.113
    少年写真新聞社, 19 Jan. 2024, 4879817899, 200, [Contributor]
  • 分散系のレオロジー : 基礎・評価・制御、応用
    鈴木, 洋, 第I編第２章第５節; 第II編第３章第３節; 第２編第２章第５節
    エヌ・ティー・エス, Aug. 2021, 9784860437312, ii, viii, 387, xp, 図版21p, Japanese, [Joint work]
  • 流れ学 流体力学と流体機械の基礎
    山田英巳; 濱川洋充; 田坂裕司, 第11章
    森北出版, 2016, [Joint work]
  • Air and water
    Yasushi Takeda; Yuji Tasaka
    Grand public, 2013, 9782759808281, French, Scholarly book, [Joint work]
  • Ultrasonic Doppler Velocity Profiler for Fluid Flow
    Yuji Tasaka, Chapter 2, Sections 4.1, 5.1, 7.2 & Appendi
    Springer, Oct. 2012, 9784431540267, English, Scholarly book, [Joint editor]
■ Lectures, oral presentations, etc.
  • Rheometry utilizing ultrasonic velocity profiling
    Yuji Tasaka
    23rd Rheology forum, 21 Oct. 2021, Japanese, Invited oral presentation
    21 Oct. 2021 - 22 Oct. 2021, [Invited]
  • Effective viscoelasticity affected by dispersed particles in non-Newtonian fluid under unsteady shear
    YOSHIDA Taiki; TASAKA Yuji; MURAI Yuichi
    The Proceedings of the Fluids engineering conference, 2020, The Japan Society of Mechanical Engineers, Japanese
    2020 - 2020,

    The dispersed particles make alignments in the sheared direction under unsteady shear flows when the fluid relaxation time is sufficiently long. The alignment changes the effective viscoelasticity because a corded-like pattern of particles functions as a macro-spring effect and reduction of particle interactions. Those experimental findings regarding the effective viscoelasticity of non-Newtonian fluids with spherical particles are found by means of ultrasonic spinning rheometry. Further numerical tests using a simple toy model assuming dispersed particles combined by spring forces considering yield stresses were conducted to clarify factors caused by the particle alignment under unsteady shear flows.

  • Liquid metal experiment for elucidating Magneto-Rayleigh-Bénard convection in a square box
    Yuji Tasaka
    Invited lecture, Italian Institute of Technology (Istituto Italiano di Tecnologia - IIT), 01 Sep. 2019, English, Public discourse
    [Invited], [International presentation]
  • Frictional drag reduction promoted by generating void waves in high-speed turbulent channel flows
    TANAKA Taiji; PARK Hyun Jin; TASAKA Yuji; MURAI Yuichi; KAWAKITA Chiharu
    The Proceedings of the National Symposium on Power and Energy Systems, 2019, The Japan Society of Mechanical Engineers, Japanese
    2019 - 2019
  • Robustness of Savonius turbine for inflow of isotropic turbulence
    MURAI Yuichi; Otomo Shuji; TASAKA Yuji; Denissenko Petr
    The Proceedings of the National Symposium on Power and Energy Systems, 2019, The Japan Society of Mechanical Engineers, Japanese
    2019 - 2019, Influence of high-intensity turbulence to the performance of a Savonious wind turbine has been investigated experimentally. The turbulent intensity and its isotropic quality are managed in a large wake region of an open-jet type wind tunnel. We have found that the rotational speed of the turbine rather increases with hep of turbulence as a constant load was subject to the turbine. This robustness to the inflow quality is attributed to the drag acting on the blade being intensified by the turbulence. Hot-wire anemometer measurement of the flow behind the turbine revealed that periodic vortex-shedding due to the blade-passing frequency was suppressed with strong turbulence in the inflow.
  • 超音波流速分布計を用いた複雑・混相液状食品の非接触物性計測
    田坂裕司
    第44回食品の物性に関するシンポジウム講演会, 09 Sep. 2017, Japanese, Invited oral presentation
    [Invited], [Domestic Conference]
  • urface switching statistics in a rotating fluid: effects of system internal noise
    Yuji Tasaka
    Invited lecture, LIMSI, 22 Jun. 2017, English, Public discourse
    [Invited], [International presentation]
  • MHD Rayleigh-Bénard convection confined by a moderate aspect ratio box
    Yuji Tasaka
    Invited lecture, Technische Universität Ilmenau, 13 Dec. 2016, English, Public discourse
    [Invited], [International presentation]
■ Syllabus
  • 流体工学特論, 2024年, 修士課程, 工学院
  • 流れの遷移と制御特論, 2024年, 修士課程, 工学院
  • エネルギー環境システム工学特別ラボラトリーセミナー, 2024年, 修士課程, 工学院
  • 流体工学特論, 2024年, 博士後期課程, 工学院
  • 流れの遷移と制御特論, 2024年, 博士後期課程, 工学院
  • エネルギー環境システム工学特別ラボラトリーセミナー, 2024年, 博士後期課程, 工学院
  • エネルギー工学概論, 2024年, 学士課程, 工学部
  • 応用数学Ⅱ, 2024年, 学士課程, 工学部
  • 流体力学Ⅱ, 2024年, 学士課程, 工学部
  • 熱流体力学演習Ⅰ, 2024年, 学士課程, 工学部
■ Affiliated academic society
  • THE JAPANESE SOCIETY FOR MULTIPHASE FLOW
  • American Physical Society
  • THE JAPAN SOCIETY OF FLUID MECHANICS
  • THE JAPAN SOCIETY OF MECHANICAL ENGINEERS
  • 日本摂食嚥下リハビリテーション学会
  • 日本化学工学会
■ Research Themes
  • 気液混相乱流境界層の発達過程で現れるボイド波のモデル化とその制御
    科学研究費助成事業
    Apr. 2024 - Mar. 2028
    朴 炫珍; 金 相元; 堀本 康文; 田坂 裕司; 村井 祐一
    日本学術振興会, 基盤研究(B), 北海道大学, 24K00796
  • Fluid flows of particle suspensions elucidated by evaluating rheological properties under unsteady shear
    Grants-in-Aid for Scientific Research
    01 Apr. 2023 - 31 Mar. 2027
    田坂 裕司; PARK HYUNJIN; 柳澤 孝寿; 堀本 康文; 村井 祐一
    粒子懸濁液のレオロジー物性，特に非定常剪断下における流動物性の評価とナノ粒子懸濁液の実効粘度およびそれを与える構造要因，および粒子懸濁液の流動研究を主題に研究を行った．
    非定常剪断下におけるレオロジー物性評価では，数10ミクロンと100ミクロン程度のサイズの異なるポリエチレン粒子をそれぞれシリコーンオイルに分散させ，密度差の小さい環境での実験を行った．これまでに開発を行ってきた超音波スピニングレオメトリを用いた計測を行い，異なる振動周波数条件での実効粘度評価を実施した．計測では当初，粒子サイズが大きな条件において，歪み速度が小さい領域において明瞭な粘度の上昇が見られた．これに対して理論検証ならびに異なる条件での検証実験を行った結果，粘度上昇は速度分布計測における誤差が原因であり，実際には粘度上昇は生じないとの結論を得た．
    ナノ粒子懸濁液の実効粘度については，これまでの研究により，濃度に応じて数百倍もの粘度上昇が生じること，および，剪断を加えることにより粘度が減少し，十分に高い歪み速度では連続相の粘度程度に漸近することが示されていた．今年度の研究ではこれを詳細に調査し，体積率が2%を超える場合に粘度上昇が発現することを見いだした．さらに，この粘度上昇とずり減粘をもたらす要因として構造の形成と崩壊に注目し，X線小角散乱と動的光散乱による構造サイズの抽出を行った．その結果として，ほぼ球形のナノ粒子が液体中でアスペクト比７程度の針状の構造を形成すること，またそれらが干渉して数百ナノ程度の大きさの構造を形成することを発見した．
    流動実験については，代替として高分子溶液を用いた対流実験を行い，動画像処理計測によりずり減粘を持つ流体の特徴的な現象を見いだした．
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 23K26028
  • 非定常レオロジー物性の評価が詳らかにする粒子懸濁液の流動現象
    科学研究費助成事業 基盤研究(B)
    01 Apr. 2023 - 31 Mar. 2027
    田坂 裕司
    日本学術振興会, 基盤研究(B), 北海道大学, 23H01333
  • Smart control of gas-liquid two-phase turbulent boundary layers for frictional drag reduction
    Grants-in-Aid for Scientific Research
    05 Apr. 2021 - 31 Mar. 2026
    村井 祐一; 田坂 裕司; PARK HYUNJIN; 熊谷 一郎; 堀本 康文; 北川 石英; 大石 義彦
    令和３年度は，以下の研究調査を進めた．一次元ボイド波伝播モデルによるPBIの適用距離の予測(朴)，３次元翼による微細気泡発生法と正味摩擦抵抗低減効果の検討（熊谷），
    高時間分解レーザーせん断応力計の開発とVITA法適用による統計評価（大石），空気充填ディンプルに形成される気膜の計測とマイクロ気膜法に関する予備調査（北川），非定常剪断流れにおける分散混相流体の実効粘度（田坂），高Reynolds数Taylor-Couette乱流の速度計測と抵抗低減（堀本），水平チャネルにおいて大型気泡群を有する2相乱流流動の直接数値シミュレーション（村井），傾斜チャンネル内の境界層で挙動する気泡抗力係数算定（村井）．間欠的気泡注入による抵抗低減効果の長距離持続化（朴），水平チャネルのボイド率急変時の乱流境界層構造のステップ応答の計測（村井）．
    これらの成果は抵抗低減における気泡運動の流体力学について IJMFに4偏，気泡を含む応力場の計測技術について Exp Fluidsに4偏，船舶抵抗低減の実スケール実験について Ocean Engに2編，気泡流の非線形流体力学について JFMに1編，その他を含めて計18編の学術雑誌に掲載された．本課題で主柱としている下記の3項目について，初年度としての進展のうち特筆すべきものに以下が挙げられる．[PBI] 気泡分布の時空間パターン制御について，船底ボイド波のKdV-Burgers方程式によるデータ解析から現象相似性が発見された．[HBC] 水中翼による局所減圧型の境界層気泡分布制御法の開発では，微細気泡分散状態とエアキャビティ状態のモード変換機構が解明された．[RMF] 超音波と光による実時間フィードバック制御の開発では，複雑せん断流体の実効粘度の周波数依存性を計測する技術が確立された．
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 21H04538
  • Drag reduction by surfactant additives: functional viscoelasticity and temper ature effects evaluation
    SAKURA program
    Apr. 2024 - Mar. 2026
    Japan Society for the Promotion of Science, Hokkaido University, Principal investigator, 120243201
  • Study on Flow Assurance and Technique Minimizing Pressure Loss for Subsea Ore-lifting
    Grants-in-Aid for Scientific Research
    05 Apr. 2021 - 31 Mar. 2025
    正信 聡太郎; 村井 祐一; 高野 慧; 山本 マルシオ; 田坂 裕司; PARK HYUNJIN
    海洋鉱物資源開発においては揚鉱ユニットが技術的な中核を担う。揚鉱ユニットの設計及び運用においては、揚鉱管・移送管内のフローアシュアランス（流路保全）分析が必須であるが、管の傾斜や動揺等を考慮した非定常の固液二相流に対するリアルタイム分析技術がないため一連の技術開発を遅延させている。そこで本研究では、超音波計測技術を独自開発し、管内を脈動する固液二相流の流動状況と圧力損失の周波数スペクトル空間での因果関係を解明してフローアシュアランス分析に適用可能な圧力損失推定手法を構築する。さらに、圧力損失を低減可能な制御デバイスを開発するとともに、内部流との相互作用が分析できる水中線状構造物の応答予測手法を構築する。
    当該年度は、以下の課題を実施した。
    【①圧力損失推定技術の開発】 鉛直管を対象とした脈動流中における時間領域圧力損失推定プログラムの基本アルゴリズムを検討するとともに、過去に構築した定常状態での圧力損失推定手法を用いて、移送管の形状変化が圧力損失に及ぼす影響を調査して、試設計した移送管に対する最適な移送条件（固相体積濃度、平均流速）を設定した。2022年度に実施を計画している、口径25Aの円管を鉛直から水平まで傾斜可能な固液二相流の移送実験計画を策定するとともに、当該実験装置を製作した。さらに、2022年度に検討予定であった口径80Aの円管を用いた移送実験計画も前倒して策定した。また、管内を流動する粗大粒子を位置特定して計数する超音波エコーグラフィの計測技術について基本信号処理アルゴリズムを開発した。
    【②圧力損失最小化技術の開発】 超音波スピニングレオメトリー(USR)により固体粒子懸濁液のレオロジーの計測を実施した。
    【③水中線状構造物の応答予測手法の開発】 内部流を考慮しない水中線状構造物挙動の応答予測プログラムを開発した。
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), National Institute of Maritime, Port and Aviation Technology, 21H04590
  • 混相/複雑流体のレオロジー物性計測を基軸とした流体科学の創成
    さきがけ
    Oct. 2021 - 2025
    国立研究開発法人 科学技術振興機構, Principal investigator
  • 液体金属対流の定量可視化実験から観た地球流体核における熱物質輸送
    科学研究費助成事業 基盤研究(C)
    01 Apr. 2020 - 31 Mar. 2023
    熊谷 一郎; 田坂 裕司; 益子 岳史
    本研究課題は、液体金属プルームの温度場と速度場の同時可視化を目的としているが、液体金属内部は可視光では見えないため、まずは既知のサーマルやジェットなどの流れについての流体実験を行い、正しく流速場が計測できているか確認するための実験を行った。温度計測については、これまで使用してきた薄型の矩形水槽の壁面に設置した感温液晶板では、１種類の液晶しか使っていないため、温度の計測範囲が限られてしまうという問題があった。そこで、かつて代表者が開発した複数の感温液晶を用いた温度場の可視化法を本課題でも適用できないか、検討を開始した。
    また２重円筒水槽を用いた対流実験については、水および非ニュートン流体を用いたレイリー・ベナール対流実験を行ってきたが、水槽の壁面が曲面となっており、ハレーションなどの影響で、可視化計測がうまくできていない状況となっていた。そこで、紫外レーザーで励起される蛍光粒子を用いた流れ場の可視化法を新たに導入し、予備実験を行なった。その結果、壁面での余計な反射光が見えなくなったため、流体中のトレーサーの励起光のみが観測可能となり、PIV（粒子画像流速計）解析によって詳細な流速場を得ることができた。相変化を伴う流体（感温膨潤性ゲル（PNiPAM）のサスペンジョン）とHele-Shawセルを用いたレイリー・ベナール対流実験においても、この紫外レーザーでの可視化は有効であるため、より精度の高い流れ場解析が可能となった。
    日本学術振興会, 基盤研究(C), 明星大学, 20K04114
  • 分散気泡のレオロジーが解き明かす混相乱流遷移のシナリオ
    科学研究費補助金（基盤研究(B)）
    Apr. 2019 - Mar. 2023
    田坂裕司
    文部科学省, Principal investigator, Competitive research funding
  • Smart control of gas-liquid two-phase turbulent boundary layer
    Grants-in-Aid for Scientific Research
    01 Apr. 2017 - 31 Mar. 2022
    Murai Yuichi
    In this project, a variety of experimental approaches were taken to investigate the effect of wall frictional drag reduction realized in turbulent boundary layers by injection of bubbles. Introducing the state-of-the-arts technique for measurement of complex high-speed two-phase turbulent flow, the fluid mechanics of drag reduction was explored. Moreover, such accumulated knowledges were utilized for actual design of the drag reduction control system applicable to large marine vessels, and its performance was demonstrated. These results were published in many international journals, indicating our presence of the research and development of this field.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 17H01245
  • Development of non-invasive inline rheometry for promoting smart factory
    2019年度A-STEP機能検証フェーズ試験研究タイプ
    Sep. 2019 - Aug. 2020
    Yuji Tasaka
    JST, Principal investigator, Competitive research funding
  • Inquisition of edge of chaos by perturbations acompanying hair-pin vortices
    科学研究費補助金（基盤研究（B)）
    Apr. 2016 - Mar. 2019
    Yuji Tasaka
    文部科学省, Principal investigator, Competitive research funding
  • 乱流パフの個性とその生存率における出生の影響
    国際共同研究加速基金（国際共同研究強化）
    Apr. 2016 - Mar. 2018
    田坂裕司
    文部科学省, Principal investigator, Competitive research funding
  • Pressure field measurement system for 3D flows around rotating wind turbines
    Grants-in-Aid for Scientific Research
    01 Apr. 2015 - 31 Mar. 2017
    Murai Yuichi
    Wind power now speads at a pace of ten folds a decade, and experiences various problems which has not been pointed out before such as lack of power estimated, blade damage with sudden unstable airflows, and flow noises claimed by residents. All of them associate to pressure field of flow. Particle image velocimetry has been contributing to experimental fluid dynamics though, it hardly produces problem-solving of the issue above. This is because PIV does not measure pressure field directly despite to its rich information of velocity vector field. In this project, we have developed several numerical and experimental systems that can measure multi-dimensional pressure field as a function of time, to improve the pace of development in trial-and-error designs of various wind turbines.
    Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 15K13861
  • Smart control of gas-liquid two-phase turbulent boundary layer
    Grants-in-Aid for Scientific Research
    01 Apr. 2012 - 31 Mar. 2017
    Murai Yuichi
    After great dissaster of east Japan 2011, our human kind is tasked to realize high energy safety and production in improved efficiency upon needs of sustainable society. Marine technoligy is one of such concerns, to which we develop turbulent frictional drag reduction method feasible to marine vessels. In this project, we have established three kinds of new techniques that convert unstable bubbly two-phase flow to controled state to save energy consumption of large ships through multiple laboratory scaled fundamental experiments to find out hidden science in bubbly turbulent boundary layer at high Reynolds numbers. We have eventually suceeded in 15% energy saving for four kinds of marine vessels demonsrated by sea-trial as well.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 24246033
  • Rhythm of magma transport in deformable porous media
    Grants-in-Aid for Scientific Research
    01 Apr. 2013 - 31 Mar. 2016
    Kumagai Ichiro; MURAI Yuichi; TASAKA Yuji
    Fluid experiments on buoyancy-driven flows in deformable gel beads layer were conducted to understand the dynamics of magma transport in a partially molten region. As an analogue material of partially molten media, a mixture of transparent hydro gel beads and viscous fluids was used. Our experimental results indicate that the intermittent nature of the volcanic activity is inherent to magma transport in a partially molten zone, which explains the spatio-temporal patterns of volcanic activity.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Meisei University, 25400457
  • New mechanism for geomagnetic polarity reversals induced by flow reversals
    Grants-in-Aid for Scientific Research
    01 Apr. 2012 - 31 Mar. 2016
    YANAGISAWA Takatoshi; TASAKA Yuji; KAGEYAMA Akira; SAKURABA Ataru; MIYAGOSHI Takehiro; SUMITA Ikuro; HAMANO Yozo
    We explored magnetoconvection and rotating convection by means of laboratory experiments and numerical simulations, to elucidate the mechanism that induces geomagnetic polarity reversals. We established a regime diagram of convection in a liquid metal under the influence of imposed horizontal magnetic field. The searched space is summarized by the relation between buoyancy and magnetic force, in which a regime exists that reversals of flow direction repeat intermittently. We found that the key mechanism for flow reversals is an occurrence of large-scale circulation in a horizontal plane. We also performed numerical simulations of dynamos in a rotating spherical shell, and clarified the relation between polarity reversals and transitions of convection flow.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Japan Agency for Marine-Earth Science and Technology, 24244073
  • Characteristics of turbulent puffs and its dependence of generation scheme
    Grants-in-Aid for Scientific Research
    2013 - 2015
    Tasaka Yuji; MURAI Yuichi
    We studied process and condition of transition to a turbulent puff that is local turbulence observed in a pipe flow as catastrophic flow transition to turbulence. (1) A fine pipe flow facility with 8 m in the pipe length and 32 mm in the inner diameter of pipe that realizes laminar flow for more than 25,000 of Reynolds number without perturbation was constructed. (2) Novel visualization technique was established to extract vortical structure in a puff effectively. Through experiments, (3) complex edge of turbulence that was found by our previous study was represented in this system and physics embedded in the complex edge was elucidated, and further, (4) influence of adding microbubbles into pipe flows were investigated statistically: turbulent puffs were stabilized by adding bubbles.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, Principal investigator, Competitive research funding, 25420103
  • Landmark design for determination of future type wind turbines
    Grants-in-Aid for Scientific Research
    2011 - 2012
    MURAI Yuichi; TASAKA Yuji
    Upon the generation that the use of wind energy grows up ten fold in every decade, a two-year project has been carried out in order to judge the vision of design method that will persist in future. The project is planed based on finding essential problems in current age to choose problems that we encounter in the next age. Five kinds of themes are selected and studied through wind tunnel experiments, numerical simulations, and on-site investigation at local wind farms.
    Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 23656123
  • Improvement of efficiency on frictional drag reduction by repetitive bubble injection
    Grants-in-Aid for Scientific Research
    2011 - 2012
    TASAKA Yuji; MURAI Yuichi
    In order to improve efficiency of frictional drag reduction technique by injecting bubbles, we investigated flow of bubble mixture and developed measurement system for efficient flow control. Experimental investigations in a bubbly channel flow suggested basic mechanism of bubble clustering from a point of view of bubble-bubble interactions. We also developed a monitoring tool of flows and bubbles using ultrasonic wave. Applicability of the tool for actual vessels was discussed.
    Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), Hokkaido University, Principal investigator, Competitive research funding, 23760143
  • Determination of the energy dissipation in the Geodynamo
    Grants-in-Aid for Scientific Research
    2009 - 2011
    HAMANO Yozo; KAGEYAMA Akira; MIYAGOSHI Takehiro; YANAGISAWA Takatoshi; TASAKA Yuji; SUMITA Ikuro; SAKURABA Ataru; TAKEDA Yasushi
    Laboratory experiments on the turbulent thermal convection of a liquid metal under ambient magnetic fields with various intensities were carried out. Consulting with the observed variations of the geomagnetic field and the results of geodynamo simulations, we tried to infer the turbulent state and the energy dissipation in the Earth's core. In the experiments, we found spontaneous reversals of the flow patterns of thermal convections within a certain range of the intensity of the magnetic fields and the Rayleigh numbers, which might be important to understand the origin of the geomagnetic field reversals.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Japan Agency for Marine-Earth Science and Technology, Coinvestigator not use grants, Competitive research funding, 21244071
  • Sweeping the unexplained factors in microbubble fluids by complex viscosity analysis
    Grants-in-Aid for Scientific Research
    2009 - 2011
    MURAI Yuichi; TASAKA Yuji; KITAGAWA Atsuhide; ISHIKAWA Masaaki; TAKEDA Yasushi
    Rheological characteristics of microbubble mixture are investigated experimentally from laminar to turbulent states to obtain following findings : Non-equilibrium deformation of bubbles in oscillatory shear provides effective viscosity higher than 10 times as that of equilibrium deformation. In transition mode to turbulence, flow modulation is suppressed with microbubble, proving the fundamental function of transition delay. Reduction in turbulent intensity, promotion of heat transfer, and emergence of new type boundary layer structure with clustering of bubbles are also found in turbulent states.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Coinvestigator not use grants, Competitive research funding, 21360077
  • Pioneering Study of PIV Technology for Large Scale Airflows
    Grants-in-Aid for Scientific Research(基盤研究(B))
    2006 - 2008
    Yasushi TAKEDA; Yuichi MURAI; Yuji TASAKA
    気流の空間的構造を定量計測するPIV(Particle Image Velocimetry)を技術開発することを目的とし3年間の研究の実施を通じて多面的な成果を上げた. 大規模な気流計測における主要な問題は, 環境負荷の少ないトレーサを開発すること, ならびに三次元非定常構造を定量捕獲するための光学設計, さらには速度ベクトルデータの高密度化であった. 平成18年度は, トレーサの開発としWatermist法, Soap Bubble法, ならびにTuft Resonance法について検討を行い, さらにPIVに適合したトレーサの注入方法を設計・検定した. これと同時に300m規模の大気流動場を三次元計測する問題点提起実験を実施した. 平成19年度は開発したトレーサ注入法と光学系を実例計測によりデモンストレーション実験した. 計測対象は竜巻のPIV計測, 樹木や鉄塔をモデル化した透過性物体の周囲空間流動のPIV計測である. 平成20年度は大気ダウンバーストを室内モデル実験置換し, カラートモグラフィックPIV技術の実証実験を実施した. これらの開発の結果, 従来まで低密度データの2次元計測に制約されてきた気流構造計測が, 3次元高密度データ取得が可能となるに至った. また応用実験から気流のもつ固有の流動場が新たに発見され, これらについてのダイナミクスを論文等で発表した.
    Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 北海道大学, Coinvestigator not use grants, Competitive research funding, 18360082
  • Turbulence in the Earth's outer core
    Grants-in-Aid for Scientific Research(基盤研究(A))
    2006 - 2008
    Yozo HAMANO; Yasushi TAKEDA; Ikuro SUMITA; Ataru SAKURABA; Takatoshi YANAGISAWA; Hiroaki TOH; Yuji TASAKA; 吉原 新
    本研究では、磁場変動の観測、室内実験、及び数値シミュレーションを相互に連携して進めた。磁場変動の観測では、北西太平洋海底の2 観測点での長期計測を実現し良質なデータを得た。室内実験では、液体金属の熱対流に水平及び垂直方向の磁場を印加し、磁場強度の増加による対流の様相並びに乱流スペクトルの変化をとらえることに成功した。数値シミュレーションでは、球殻熱対流ダイナモを数多くの設定で実現し詳細な解析を行った。これらを総合することで、地球流体核の乱流状態に関する示唆が得られた。
    Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(A), 東京大学->独立行政法人海洋研究開発機構, Coinvestigator not use grants, Competitive research funding, 18204038
  • 液-液体金属二層流れの振る舞いを知るための実験研究
    科学研究費補助金(若手研究(B))
    2006 - 2007
    田坂 裕司
    液-液体金属二層流れは,地球物理学におけるコアーマントル境界の問題からシリコン単結晶生産における品質管理まで,幅広い分野に関係する現象である.それらの問題を解決するため主に以下に示す4つのテーマで事件研究を遂行し,それぞれ結果を得た.(1)液体金属内熱対流と磁場による制御 複数線での超音波流速分布計測(UVP)により、液体ガリウム中に形成される対流セルの3次元運動を調べた.また、得られた速度分布変動と、サーミスタによる温度計測結果の周波数解析を行い、時間変動のスケールを明らかにした.さらに,ヘルムホルツコイルにより形成された一様磁場による制御に取り組み,対流中に現れる短い時間スケールの変動を抑制すると共に,対流セルの上記のサイズを変化させることに成功した.(2)液体金属のスピンアップにおける過渡的な流れを用いた実効粘性と透磁率の測定 一様磁場中に置かれた円筒に液体金属を満たし回転させ、スピンアップ時の過渡的な変動磁場と速度分布変化を計測した.この結果から液体金属の磁場中における実効粘性と透磁率を求めた.計測はおもにフランス、非平衡現象研究所(IRPHE)で行った.(3)自由界面を有する回転流れの表面形状Switching現象 この現象に関して,流れを理解するための実験研究を行い,それを制御するための知見を得た.また液体金属は粘性の効果が小さく乱れやすいが,表面張力が大きく界面...
    文部科学省, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 18760116
■ Industrial Property Rights
  • レオロジー物性演算装置、レオロジー物性計測システム、レオロジー物性演算方法及びレオロジー物性演算プログラム
    Patent right, 田坂裕司; 大家広平, 国立大学法人北海道大学
    特願2025-129856, 04 Aug. 2025
  • 非接触型レオロジー物性計測装置、システム、プログラムおよび方法
    Patent right, 田坂裕司; 芳田泰基; 村井祐一
    特願2019-056493, 25 Mar. 2019
    特許7412786
  • 超音波物性測定装置
    Patent right, 田坂裕司; 芳田泰基; 大家広平, 国立大学法人北海道大学
    特願2021-029219, 25 Feb. 2021
  • 流体モニタリング装置およびそれを用いた船体摩擦抵抗低減システム
    Patent right, 田坂裕司; 村井祐一; 武田靖
    特願2010-023385, 04 Feb. 2010
    特許5532220
    09 May 2014
  • 回転翼式気泡発生装置
    Patent right, 村井祐一; 田坂裕司; 熊谷一郎
    特願2010-039873, 25 Feb. 2010
    特許5501028
    20 Mar. 2014
  • Ultrasonic multiphase flowmeter, ultrasonic multiphase flow rate measurement program, and multiphase flow rate measurement method using ultrasonic wave
    Patent right, Y.Takeda; Y.Murai; Y.Tasaka
    特願2009-541148, 12 Nov. 2008
    特許5208124
    01 Mar. 2013

Research Profiles

■ Research Profiles