Researcher basic information

• Doctor of Engineering, Osaka University

• https://researchmap.jp/read0116753?lang=en

• https://jglobal.jst.go.jp/detail?JGLOBAL_ID=200901052121013779
• https://www.eng.hokudai.ac.jp/labo/trans/

• 80315168

• 200901052121013779

• 微粒子分散系
• 粒子流
• 混相流
• Granular flow
• Multiphase Flow

• Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering), Fluid engineering
• Energy Engineering, Earth resource engineering, Energy sciences
• Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering), Transport phenomena and unit operations

• Bachelor's degree program, School of Engineering
• Master's degree program, Graduate School of Engineering
• Doctoral (PhD) degree program, Graduate School of Engineering

Research activity information

• Mechanism of Inverse and Sandwich Density Segregations in Vibrated Particle Bed
  Konno, H.; Katayama, T.; Harada, S.; Ogata, K.
  Physical Review E, 112, 015408, 2025, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Numerical Investigation of Pore Characteristics in Compacted Sand Layers, –Physical Interpretation of Applicability of Kozeny-Carman Equation–
  Miura, O; Oishi, R; Harada, S; Yagi, T
  Geophysics, 90, 3, 227, 237, 2025, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Three-dimensional Wireless Measurement of Float–Sink Object Motions in a Gas–Solid Fluidized Bed
  Katayama, T; Otsuka, Y; Saito, S; Harada, S; Tsuji, T; Oshitani, J
  International Journal of Multiphase Flow, 176, 104817, 2024, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Visualization of Mixing Upper and Lower Stratified Suspensions Using Red and Blue Fluorescent Particles
  Tanaka, Y; Iwaguchi, T; Yamamoto, Y; Otomo, R; Harada, S
  Multiphase Science and Technology, 36, 2, 29, 39, 2024, [Peer-reviewed]
  English, Scientific journal
• Fabrication of Realistic Transparent Porous Media for 3D Observation of Internal Mass Transport
  Gyotoku, T; Iwaguchi; T. Hanya; Harada, S; Tanaka, Y; Yamamoto, Y
  Journal of Porous Media, 27, 2, 43, 55, 2024, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Variation in the Settling Behavior of Particulate Suspension in Saturated Porous Media
  Gyotoku, T; Masuda, G; Nishimura, K; Harada, S; Tanaka, Y; Yamamoto, Y
  Journal of Porous Media, 27, 1, 35, 47, 2024, [Peer-reviewed], [Corresponding author]
  English
• Quantitative Evaluation of the Pore Characteristics in Platelet Particle Beds by Pore Network Modeling
  Yamamoto, K; Ishiyama, K; Harada, S
  Transport in Porous Media, 150, 89, 103, 2023, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Influence of Air Velocity and Powder Bed Height on Local Density in a Gas–Solid Fluidized Bed and Float–Sink of Spheres
  Oshitani, J; Kato, S; Tsuji, T; Washino, K; Harada, S; Sakamoto, Y; Kajiwara, H; Matsuoka, K; Franks, G
  Advanced Powder Technology, 34, 104146, 2023, [Peer-reviewed]
  English, Scientific journal
• Wireless Measurement of Float--Sink Motion of Variously-shaped Objects in Gas--Solid Fluidized Bed
  Uemoto, K; Narita, S; Harada, S; Sakamoto, Y; Tsuji, T; Oshitani, J; Kajiwara, H; Matsuoka, K
  Advanced Powder Technology, 34, 9, 104111, Elsevier BV, 2023, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Tortuosity in Platelet Particles with Various Structures
  Ishiyama, K; Harada, S; Yagi, T
  Transport in Porous Media, 148, 3, 1, 23, 2023, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Diffusive Behavior of Fine Particle Assemblage Passing through Nonuniform Granular Porous Media
  Otomo, R; Nakano, Y; Harada, S
  Particulate Science and Technology, 41, 7, 940, 952, 2023, [Peer-reviewed]
  English, Scientific journal
• Mass Transfer from Mobile to Immobile Regions in Irregularly-Shaped Micro-Channels at Low Reynolds Number
  Toyama, K; Togi, F; Harada, S
  Groundwater, 61, 5, 639, 647, 2023, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Experimental Verification of the Brinkman Equation around Objects with Various Shapes in Gas-Solid Stationary and Fluidized Beds
  Honda, Y; Saito, S; Anzai, T; Harada, S; Tsuji, T; Washino, K; Oshitani, J; Kajiwara, H; Matsuoka, K
  International Journal of Multiphase Flow, 160, 104359, 2023, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Effects of Terminal Velocities on Macroscopic and Microscopic Hydrodynamic Mixing of Stratified Suspensions
  Yamamoto, Y; Otomo, R; Tanaka, Y; Harada, S
  Physical Review E, 106, 045109, 2022, [Peer-reviewed]
  English, Scientific journal
• FPM-SE: a Numerical Model for Dense Gas--Solid Flows with Large Non-Spherical Object
  Tsuji, T; Sakamoto, Y; Harada, S; Uemoto, K; Oshitani, J; Washino, K; Tanaka, T; Kajiwara, H; Matsuoka, K
  Chemical Engineering Science, 264, 118149, 118149, Elsevier BV, 2022, [Peer-reviewed]
  Scientific journal
• Theoretical Consideration of the Rheological Properties of Particulate Dispersions with Aggregates
  Tanii, Y; Kamata, N; Saito, H; Harada, S; Sawada, M
  Physics of Fluids, 34, 093309, 2022, [Peer-reviewed], [Corresponding author]
  Scientific journal
• 高ポロシティを有する繊維層および粒子層中の空隙ネットワークと流体透過特性の解析 (ボロノイ分割を利用した空隙構造と動水半径の評価)
  大友涼子; 出口裕仁; 原田周作
  混相流, 36, 266, 273, 2022, [Peer-reviewed]
• Structural Transition of Various-Sized Sphere-Platelet Mixtures
  item Tani, A; Ishiyama, K; Tanii, Y; Harada, S; Satoh, H
  Physical Review E, 105, 044602, 2022, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Macroscopic and Microscopic Hydrodynamic Mixing of Stratified Suspensions
  Yamamoto, Y; Yamada, K; Tanaka, Y; Harada, S
  Physical Review E, 104, 2, 025111, American Physical Society (APS), 2021, [Peer-reviewed]
  English, Scientific journal
• Unstable Sinking of Spheres at Higher Air Velocity in a Gas-Solid Fluidized Bed
  Oshitani, J; Sasaki, T; Tsuji, T; Harada, S; Kajiwara, H; Matsuoka, K
  Advanced Powder Technology, 32, 4, 1300, 1304, 2021, [Peer-reviewed]
  English, Scientific journal
• Quantitative Evaluation of Solute Dispersion in Irregularly Shaped Micro-Channels
  Togi, F; Kubota, T; Toyama, K; Ishida, A; Harada, S
  Microfluidics and Nanofluidics, 24:57, 1, 8, 2020, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Possibility of Non-Fickian Mixing at Concentration Interface between Stratified Suspensions
  Mori, M., Tai, T., Nishimura, K., Harada, S., Yamamoto, Y.
  Journal of Colloid and Interface Science, 571, 13, 20, 2020, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Non-Invasive Measurement of Floating-Sinking Motion of a Large Object in a Gas-Solid Fluidized Bed
  Yoshimori, W; Ikegai, T; Uemoto, K; Narita, S; Harada, S; Oshitani, J; Tsuji, T; Kajiwara, H; Matsuoka, K
  Granular Matter, 21, 3, :42 1, 11, 2019, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Scale-Independent Model of Gravitational Dispersion of Particulate Suspension in Fractal Channel
  Kurose, Y; Ishizawa, K; Soriano, M. R; Harada, S
  Chemical Engineering Science, 199, 231, 239, 2019, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Monte Carlo Analysis of Montmorillonite Particle Structures and Modeling of Dissolution Rate Reduction
  Terada, K; Tani, A; Harada, S; Satoh, H; Hayashi, D
  Materials Research Express, 6, 3, 035514, 2018, [Peer-reviewed]
  English, Scientific journal
• Quantitative Evaluation of Mass Transfer near the Edge of Porous Media by Absorption Photometry
  Taiki Tanikoshi; Ryoko Otomo; Shusaku Harada
  AIChE Journal, 63, 2, 823, 833, Feb. 2017, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Dynamic Vertical Forces Working on a Large Object Floating in Gas-Fluidized Bed: Discrete Particle Simulation and Lagrangian Measurement
  Kyohei Higashida; Kenta Rai; Wataru Yoshimori; Tomoki Ikegai; Takuya Tsuji; Shusaku Harada; Jun Oshitani; Toshitsugu Tanaka
  Chemical Engineering Science, 151, 105, 115, Sep. 2016, [Peer-reviewed]
  English, Scientific journal
• Restructuring Capability of Non-Fractal Aggregate in Simple Shear Flow
  Uyen Tu Lieu; Shusaku Harada
  Advanced Powder Technology, 27, 4, 1037, 1046, Jul. 2016, [Peer-reviewed]
  English, Scientific journal
• Strength Deterioration of Nonfractal Particle Aggregates in Simple Shear Flow
  Kento Horii; Reiko Yamada; Shusaku Harada
  Langmuir, 31, 29, 7909, 7918, Jul. 2015, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Numerical simulation of concentration interface in stratified suspension: Continuum-particle transition
  Yasufumi Yamamoto; Fumiya Hisataka; Shusaku Harada
  INTERNATIONAL JOURNAL OF MULTIPHASE FLOW, 73, 71, 79, Jul. 2015, [Peer-reviewed]
  English, Scientific journal
• Stability of Restructured Non-Fractal Aggregates in Simple Shear Flow
  Uyen Tu Lieu; Shusaku Harada
  Advanced Powder Technology, 26, 3, 705, 710, May 2015, [Peer-reviewed]
  English, Scientific journal
• Mass Transfer Caused by Gravitational Instability at Reactive Solid-Liquid Interfaces
  Ryoko Otomo; Nobuhiko Ishii; Keita Takahashi; Shusaku Harada
  Journal of Visualization, 17, 1, 49, 57, Feb. 2014, [Peer-reviewed]
  English, Scientific journal
• Collective settling of fine particles in a narrow channel with arbitrary cross-section
  Shusaku Harada; Megumi Kondo; Kensuke Watanabe; Taiga Shiotani; Kodai Sato
  Chemical Engineering Science, 93, 307, 312, Apr. 2013, [Peer-reviewed], [Lead author, Corresponding author]
  English, Scientific journal
• Fluid Permeability in Stratified Unconsolidated Particulate Bed
  Ryoko Otomo; Shusaku Harada
  Transport in Porous Media, 96, 3, 439, 456, 2013, [Peer-reviewed]
  English, Scientific journal
• Effect of different soil layers on porewater to remediate acidic surface environment at a close mine site
  Omar R. Salinas Villafane; Toshifumi Igarashi; Shusaku Harada; Mitsuru Kurosawa; Toshio Takase
  Environmental Monitoring and Assesment, 184, 12, 7665, 7675, Dec. 2012, [Peer-reviewed]
  English, Scientific journal
• Particle-like and fluid-like settling of a stratified suspension
  S. Harada; T. Mitsui; K. Sato
  European Physical Journal E, 35, 1, 1, 6, Jan. 2012, [Peer-reviewed], [Lead author, Corresponding author]
  English, Scientific journal
• Direct measurement of fluid force on a particle in liquid by telemetry system
  Shusaku Harada; Yosuke Kobayashi; Takanori Sawano; Emi Noguchi
  INTERNATIONAL JOURNAL OF MULTIPHASE FLOW, 37, 8, 898, 905, Oct. 2011, [Peer-reviewed]
  English, Scientific journal
• End effect on permeability of loose particulate bed having different internal structures
  R. Otomo; S. Harada
  Particulate Science and Technology, 29, 1, 2, 13, Jan. 2011, [Peer-reviewed]
  English, International conference proceedings
• Diffusive behavior of a thin particle layer in fluid by hydrodynamic interaction
  Shusaku Harada; Ryoko Otomo
  PHYSICAL REVIEW E, 80, 6, 066311, Dec. 2009, [Peer-reviewed]
  English, Scientific journal
• Structural change in non-fractal particle clusters under fluid stress
  S. Harada; R. Tanaka; H. Nogmi; M. Sawada; K. Asakura
  COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, 302, 1-3, 396, 402, Jul. 2007, [Peer-reviewed]
  English, Scientific journal
• Dependence of fragmentation behavior of colloidal aggregates on their fractal structure
  S. Harada; R. Tanaka; H. Nogami; M. Sawada
  JOURNAL OF COLLOID AND INTERFACE SCIENCE, 301, 1, 123, 129, Sep. 2006
  English, Scientific journal
• Wave propagation in a dynamic system of soft granular materials
  S Harada; S Takagi; Y Matsumoto
  PHYSICAL REVIEW E, 67, 6, 061305, Jun. 2003
  English, Scientific journal
• Spouting of fine powder from vertically vibrated bed
  S Harada; H Li; K Funatsu; Y Tomita
  CHEMICAL ENGINEERING SCIENCE, 57, 5, 779, 787, Mar. 2002, [Peer-reviewed]
  English, Scientific journal
• Fluid force acting on a particle falling toward a wall
  Syusaku Harada; Toshitsugu Tanaka; Yutaka Tsuji
  JSME International Journal, Series B: Fluids and Thermal Engineering, 44, 4, 520, 525, Nov. 2001
  English, Scientific journal
• Granular jump in low velocity pneumatic conveying of solid particles in a horizontal pipeline
  Y. Tomita; K. Funatsu; S. Harada
  Handbook of Powder Technology, 10, 353, 359, 2001
  English, Scientific journal
• Fluid force acting on a particle falling toward a wall
  Syusaku Harada; Toshitsugu Tanaka; Yutaka Tsuji
  Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 66, 649, 2313, 2319, Japan Society of Mechanical Engineers, 2000, [Peer-reviewed]
  Japanese, Scientific journal
• Numerical Study of Motion of Solid Cylinder Falling to Wall in Fluid
  HARADA Syusaku; TANAKA Toshitsugu; TSUJI Yutaka
  Transactions of the Japan Society of Mechanical Engineers. Series B., 65, 633, 1520, 1527, The Japan Society of Mechanical Engineers, 1999, [Peer-reviewed]
  Japanese, A numerical analysis of incompressive flow around a solid cylinder which falls to a solid wall was performed to study the effect of fluid on the interaction between solid bodies. A time-dependent boundary-fitted coordinate system and a transformable grid which moves arbitrarily were adopted in order to express unsteady and relative motion of solid boundaries. The fluid force acting on the cylinder was calculated directly by integrating the stress and the pressure on the surface without using any models. The effect of the induced pressure on the behavier of the cylinder was studied, and the results were compared with the analytical theory of lubrication. The obtained pressure in the gap showed similar profiles to the one derived from the lubrication theory. Furthermore, it was studied about dominant effects on the motion of the cylinder in the fluid, especially about the effect of the unsteady motion of the cylinder. In addition, it was examined the effect of the inclination of the wall to the motion of the cylinder.
• Numerical analysis of dense phase liquid-solid flow in a horizontal pipe
  S Harada; T Tanaka; Y Tsuji; K Asakura
  Fluid Mechanics and Its Application: IUTAM Symp. Lubri, Trans. Viscous Mater., 43, 31, 42, 1998
  English, International conference proceedings
• Three-Dimensional Simulation of Solid-liquid Flows with Highly Concentrated and Large Particles
  ASAKURA Kuniomi; FUNAYAMA Takaaki; HARADA Syusaku; NAKAJIMA Iwao
  Journal of MMIJ, 114, 6, 403, 409, The Mining and Materials Processing Institute of Japan, 1998, [Peer-reviewed]
  Japanese, In this study, solid-liquid flows with coarse particles, which form a highly concentrated zone in a pipe, were simulated. In general, the cell size of the continuous phase is larger than the particle size. However, with increases in particle size, the cell size must be close to the particle size in order to maintain high resolution of the fluid velocity. Simulation using equal cell and particle sizes was carried out to investigate the effects of fluid velocity, pressure gradient and void fraction on the settling motion of a particle in rest water. For simulating a particle cloud, a conventional Lagrangian/Eulerian method using the drag coefficient of a particle cloud was employed. The results so obtained were compared with the results using the drag coefficient of a single particle under the same flow and particle conditions.
• Simulation of descending particles in water by the distinct element method
  K. Asakura; S. Harada; T. Funayama; I. Nakajima
  Powder Technology, 94, 3, 195, 200, 1997, [Peer-reviewed]
  English, Scientific journal
• 水中落下粒子群の離散要素法によるシミュレーション
  朝倉國臣; 原田周作; 舟山高明; 中島 巌
  資源と素材, 112, 4, 219, 224, 1996, [Peer-reviewed]

• 重力下における液中微粒子の集団性
  原田周作, ながれ, 34, 5, 321, 326, 2015
• 固体粒子を含む液体の流れに関する研究
  原田周作, 混相流, 27, 2, 183, 186, 2013
• 微粒子懸濁液の集団的挙動と個別的挙動
  原田周作, 塗装工学, 48, 6, 204, 209, 2013
• Lagrangian Sensor for Measurement of Fluid Force
  HARADA Shusaku, Journal of the Research Association of Powder Technology, Japan, 49, 7, 538, 545, 2012
  We have made a Lagrangian sensor for real-time and non-invasive measurement of fluid force acting on a particle which moves freely in liquid. The sensor particle contains an acceleration sensor, magnetometer, microcomputer, wireless signal transmitter module and cells. The acceleration sensor detects the acceleration of particle （acting force divided by mass） for each instant of time. The magnetometer detects the direction of external magnetic field, which is oriented in the same direction as the gravity, for the removal of gravitational acceleration from acceleration signals with arbitrary attitude of particle. We have performed some preliminary experiments in order to check the accuracy of the measurement system. The measured results agree well with the theoretical prediction of particle motion in liquid. Moreover, we applied the Lagrangian sensor to a multi-particle system for the measurement of fluid force under the influence of other particles., The Society of Powder Technology, Japan, Japanese
• 濃度界面が引き起こす液中微粒子の集団運動
  原田周作, 可視化情報学会誌, 32, 126, 14, 18, 2012
• 微粒子分散系の動的特性
  原田周作, 物性研究, 88, 2, 281, 288, 2007
• Hydrodynamic Diffusion of Particles in Microscale
  Harada Shusaku, Journal of the Research Association of Powder Technology, Japan, 42, 11, 799, 803, 2005
  Sedimentation of solid particles is an important phenomenon in various engineering processes related to coating, accumulation, separation, filtration and so on. It is well-known that the sedimentation velocity in a stationary fluid is influenced by hydrodynamic interactions between particles and is a function of volumetric concentration of particles. In addition, the hydrodynamic interactions induce complex effects, such as the large-scale fluctuations in the sedimentation velocity, the self-diffusion of particles and the instability at the interface of sedimenting suspension. In this paper, the hydrodynamic diffusion, which is one of the hydrodynamic effects, of particle layer with a finite height is discussed. Researches on the hydrodynamic diffusion are reviewed and our recent numerical studies on the diffusivity of particles in microscale are reported., The Society of Powder Technology, Japan, Japanese
• 外力により発生する粒子噴流
  原田周作, 噴流工学, 21, 1, 13, 18, 2004
  日本ウォータージェット学会, Japanese
• 固液二相流における固体間の近接相互作用
  原田周作, 混相流, 15, 3, 252, 257, 2001
• 固気二相流の流動様式と可視化
  富田侑嗣; 原田周作, 14, 2, 158, 165, 2000

• 流体力学ハンドブック (日本流体力学会編)
  原田周作
  東京大学出版会（刊行予定）, 2023, [Contributor]
• 粉粒体の構造制御・ハンドリング技術
  原田周作
  技術情報協会, 2013, [Contributor]
• ながれの事典
  原田周作
  丸善, 2004, [Contributor]

• 連続体・不連続体力学, 2024年, 修士課程, 工学院
• 連続体・不連続体力学, 2024年, 修士課程, 工学院
• 連続体・不連続体力学特論, 2024年, 修士課程, 工学院
• 連続体・不連続体力学特論, 2024年, 修士課程, 工学院
• 連続体・不連続体力学特論, 2024年, 博士後期課程, 工学院
• 連続体・不連続体力学特論, 2024年, 博士後期課程, 工学院
• 資源循環システム実験Ⅰ, 2024年, 学士課程, 工学部
• 資源循環システム実験Ⅲ, 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, 2024年, 学士課程, 工学部
• 流体力学演習, 2024年, 学士課程, 工学部
• 資源工学概論, 2024年, 学士課程, 工学部

• THE SOCIETY OF CEMICAL ENGINEERS, JAPAN
• 粉体工学会
• 日本混相流学会
• 日本機械学会
• 資源・素材学会

• 初生制御による気泡の成長競争と集団運動の力学解明
  科学研究費助成事業
  Apr. 2024 - Mar. 2027
  渡村 友昭; 高木 周; 杉山 和靖; 高比良 裕之; 原田 周作
  日本学術振興会, 基盤研究(B), 東京大学, 24K00799
• Hydrodynamic systematization of mixing phenomena - Collectivity and individuality of particulate suspension -
  Grants-in-Aid for Scientific Research
  01 Apr. 2023 - 31 Mar. 2026
  原田 周作; 田中 洋介; 山本 恭史
  微粒子分散系の濃度界面で生じる流体力学的混合の解明を目的とした研究を行った．個々の粒子スケールで生じる微視的混合と，集団運動のスケールで生じる巨視的混合の関係性について調べるために，紫外線を照射させることにより異なる波長で蛍光する特殊な微粒子を2種類作製し，外部からUVレーザーを照射することで液体中における異種粒子の混合挙動を調べた．濃度の不連続面が形成されるような粒子沈降実験装置を作製し，不連続面近傍の粒子混合挙動を撮影した．得られた実験画像を分光して粒子の判別を行うことにより，粒子の巨視的な混合距離を定量化した．その結果，粒子の混合距離は，理論的に導出された微粒子の集団性および沈降速度比を含む無次元数によって定量的に予測可能であることを実験的に確認した．
  さらに，複雑形状を有する流路中の微粒子分散系の集団性と濃度界面挙動について調べることを目的として，屈折率マッチング法とレーザースキャニング法を併用した微粒子濃度界面の3次元形状測定システムを開発した．任意の空隙サイズを有する複雑流路を作製するために，スピノーダル分解の数値解析を行った．数値解析結果を利用して，種々の水力平均直径を有する多孔質状の複雑流路を設計し，透明レジンを材料として3Dプリンティングにより供試体を作製した．また空隙を飽和させる液体の屈折率を調整することで流路部を透明化し，下部から照射したシート状レーザーをスキャンすることにより複雑流路内部の微粒子挙動の観察を可能とした．開発した測定システムを用いて，濃度界面を伴う微粒子沈降実験を行った．その結果，濃度勾配が重力と逆方向に正となるような条件での微粒子沈降は，粒子直径や濃度に大きく依存し，特定の空隙部分を微粒子が集団的に沈降するなど複雑な挙動を示すことが明らかとなった．
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 23K26029
• Hydrodynamic systematization of mixing phenomena - Collectivity and individuality of particulate suspension -
  Grants-in-Aid for Scientific Research
  01 Apr. 2023 - 31 Mar. 2026
  原田 周作; 田中 洋介; 山本 恭史
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 23H01334
• 混合廃棄物の乾式素材分離技術の高度化に向けた流動層内での物体浮沈メカニズムの解明
  科学研究費助成事業
  01 Apr. 2021 - 31 Mar. 2025
  押谷 潤; 原田 周作; 辻 拓也
  昨年度までは球形物体の浮沈について主に研究したが、今年度は混合廃棄物を主に構成する非球形物体の浮沈について研究した。まず、浮揚すべき密度の物体に注目し、昨年度まで使用していた直径30mmの球と同体積の立方体およびアスペクト比が異なる棒状直方体４つと扁平比が異なる板状直方体４つの計９つについて風速を変化させて粒径の小さな粉体の流動層内での浮沈を調べた結果、棒状直方体では球と同様の浮沈となったのに対し、板状直方体では扁平比が大きい薄くて面積が大きなものでは流動化しない粉体が面上に存在するために浮揚すべき風速で沈降する結果となった。一方、磁気センサと加速度センサを内包した球形と非球形の物体を用い、粒径の大きな粉体の流動層内での浮沈を無線式センサシステムで調べた結果、球形では沈降する密度の場合に棒状や板状では沈降と浮揚を繰り返すことが明らかとなると共に、同様の傾向が数値シミュレーションにおいても得られた。また、昨年度までは１つの物体の浮沈を研究したが、混合廃棄物を浮沈分離する上では一度に多量の処理が求められるため、今年度は複数の物体の浮沈（多体効果）について研究した。その結果、多体にしても低密度の物体は浮揚し、高密度の物体は沈降するのに対し、流動層の見掛け密度よりもわずかに小さい物体の場合、１個では浮揚するが個数の増加と共に浮揚する割合が低下し、投入物体全ての投影面積の割合が流動層断面積の50%を超えると全て沈降することが明らかとなった。以上の結果、粉体の粒径が非球形物体の浮沈に影響を及ぼすことと密度差通りの浮沈を行うためには物体処理量に注意が必要であることが見出され、研究課題名に挙げた混合廃棄物の乾式素材分離技術の高度化に向け、有意義な結果が得られたと思われれる。
  日本学術振興会, 基盤研究(B), 岡山理科大学, 23K21772
• 混合廃棄物の乾式素材分離技術の高度化に向けた流動層内での物体浮沈メカニズムの解明
  科学研究費助成事業
  01 Apr. 2021 - 31 Mar. 2025
  押谷 潤; 原田 周作; 辻 拓也
  流動化させる粉体として粒子径の異なるガラスビーズを用い、流動層の風速と層高を変化させて様々な密度の球の浮沈実験を行った。いずれの粒子径においても層高が低く風速が小さい場合において浮力と重力を基本とするアルキメデスの原理に基づくような浮沈挙動が確認され、粉体の質量／(流動層の断面積×高さ)で求まる流動層の見掛け密度よりも小さな密度の球が浮揚し、大きな球が沈降した。一方、層高が高く風速が大きい場合は密度差から沈降すると予想された球が沈降せず層内を漂うという興味深い結果が得られ、流動層内での物体浮沈が条件によってはアルキメデスの原理に基づかないことが明らかとなった。そこで、流動層内の球に対して浮力と重力以外に働く力の存在を検討するために、無線式センサシステムを構築した。磁気センサと加速度センサおよびそれらの信号を無線発信する機器を内蔵した球を作成して実験を行った結果、アルキメデスの原理に基づく浮力よりも大きな鉛直上向きの力が定常的ではないがごく稀に急に働くことが明らかとなった。さらに、流動層内での物体浮沈について数値シミュレーションを行った結果、上記の実験と同様に低風速では安定した物体浮沈が再現されたのに対し、風速が大きい場合ではアルキメデスの原理から沈降すると予想された球が沈降せずにある瞬間に大きな鉛直上向きの力を受けて浮揚するという興味深い結果を得た。以上の結果は、研究課題名に挙げた混合廃棄物の乾式素材分離技術の高度化に向け、粉体の粒子径や層高、風速の大小が安定した物体浮沈を阻害する可能性を示唆するものであり有意義であると思われる。
  日本学術振興会, 基盤研究(B), 岡山理科大学, 21H03646
• Unified interpretation of dynamics of immiscible and miscible interfaces -Mixing mechanism of materials at meso-scales
  Grants-in-Aid for Scientific Research
  01 Apr. 2019 - 31 Mar. 2022
  Harada Shusaku
  The objective of this study is to elucidate kinetics of micron-sized particulate dispersion and the mixing phenomena of particles at concentration interface. We measured a three-dimensional shape of the concentration interface of particles settling in liquid. The measured results showed that various settling modes appear due to the change in miscibility and immiscibility of the concentration interface.
  Experiments and numerical analyses on the mixing of particles near the concentration interface were also performed. The results showed that a particle-scale mixing (microscopic mixing) and a large-scale mixing due to gravity-induced instability (macroscopic mixing) appeared dependent on the collectivity and settling velocity of upper and lower particles.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 19H02058
• Microscopic interpretation of concentration interface and active control of particulate suspension system
  Grants-in-Aid for Scientific Research
  01 Apr. 2014 - 31 Mar. 2017
  Harada Shusaku
  Collective settling of fine particles in liquid have been studied numerically, theoretically and experimentally. The existence of concentration interface, which is an apparent interface between suspended particles and pure fluid, plays a significant role in the collective motion of suspended particles. We examined relative motion of particles to surrounding flow near the concentration interface microscopically and found the mechanism of collectivity of particles. We also investigated the collective settling of suspended particles in a complicated channel and develop a physical model on dispersion behavior of particle in the channel.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 26420095
• Self-sealability of fractures in rock and its application to fracture and strength control
  Grants-in-Aid for Scientific Research
  01 Apr. 2010 - 31 Mar. 2014
  KANEKO Katsuhiko; KAWASAKI Satoru; NARA Yoshitaka; ITO Mayumi; MUKUNOKI Toshifumi; HIROYOSHI Naoki; SAKAGUCHI Kiyotoshi; HARADA Syusaku
  A series of experimental studies on the sealability of fracture has been performed and its application to geotechnical engineering has been discussed. Firstly, analyzing the influence of environments on the sub-critical crack growth in rock, the mechanism of crack growth has been clarified. Secondarily, the self-sealing process of fracture in the rocklike material in water was investigated and the mechanism of self-sealing was clarified. Thirdly, the process of fracture propagation was analyzed numerically and a design method to control fracture propagation, i.e., crack orientation and so on. From these results, a method to estimate the long-term strength of rock has been proposed. Furthermore it is pointed out that the strength of rock can be controlled by controlling the environmental condition.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 22246114
• Collective and individual motions of particulate dispersion with concentration interface
  Grants-in-Aid for Scientific Research
  2011 - 2013
  HARADA Shusaku; YAMAMOTO Yasufumi
  Collective motion of fine particles in liquid can be widely seen in engineering processes such as water treatment or sediment transport. We have studied whether collective or individual settling motion of particles reveals in liquid. The results showed that the concentration interface which is an ambiguous interface between suspended particles and pure fluid plays a significant role in these extreme behaviors. In cases of small particle size with high concentration, the interfacial instability occurs at the lower concentration interface and consequently the settling velocity is much faster than that of an isolated particle. On the other hand, in case of large particles with low concentration, the concentration interface is less distinct and the suspended particles settle individually. We showed that the transition from these collective to individual motions of suspended particles can be controlled by the border resolution of concentration interface.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 23560178
• The study of the stabilization of carbon dioxide and the development of new energy through the use of marine biomass
  Grants-in-Aid for Scientific Research
  2010 - 2012
  SENAHA Izuru; KONISHI Teruko; TAIRA Toki; TAMAKI Shirou; FUJIMURA Hiroyuki; ISHIKAWA Masaaki; WAKAI Kensuke; OOSHIRO Naoki; ODA Takuya; HIRAOKA Masanori; HARADA Syusaku
  In this research, CO2 emitted from thermal power plants and sewage treatment equipment are used as resources for the cultivation of marine algae. By artificially dissolving high concentrations of CO2 into seawater and using it to grow marine algae, photosynthesis (i.e. growth rate) of marine algae becomes significantly rapid. The growth rate of marine algae will be accelerated by more than 1.9 times, as compared to that in normal seawater. Moreover, we tried making a bio-ethanol using the marine algae, and succeed. Thus, we developed the "carbon recycle system" which reduces CO2 and reuses CO2 as new resources.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), University of the Ryukyus, 22310057
• テレメトリシステムを用いた液中粒子のダイナミクスに関する研究
  科学研究費助成事業
  2003 - 2004
  原田 周作
  近年、ナノ・マイクロテクノロジーの発展に伴い,特定の波長の光を吸収する半導体粒子などの機能性微粒子の研究が盛んに行われており,溶媒中における微粒子挙動の解明が求められている.しかしながら低Reynolds数条件における粒子間の流体力学的相互作用は長距離性を有すること,また近接極限において連続体近似が破綻することなど複雑な因子を多く含むため,溶媒中における微粒子の分散・凝集のダイナミクスはほとんど明らかにされていない.本研究では,このような粘性流体中における固体粒子のダイナミクスに関連する研究として,粒子の自由運動にともなう位置および加速度変化を同時測定し,さまざまな条件における固体間の流体力学的相互作用の詳細を調べた.3種類の液中粒子の加速度計測用センサ粒子(以下,センサ粒子)を製作した.ピエゾ抵抗型微小加速度センサ,信号増幅部および電源部からなる小型回路をアクリル製中空粒子に内蔵し,データ取得のために,テレメトリ回路による無線送信,内蔵マイクロロガーによるデータ蓄積,微細エナメル線による有線通信の3手法を用いた回路を製作した.また外部からLED変位計,レーザ変位計を併用した粒子変位の非接触測定を行った.外部からの粒子変位測定により,低Reynolds数条件における粒子-固体壁面の接近時の粒子挙動が明らかとなった.固体壁面への接近時に潤滑効果による過大な流体力が作用し,壁面近傍で急激な減速運動を行う粒子の加速-減速過程は,低Reynolds数条件の定常流体力および非定常流体力の線形和により得られる粒子軌跡と定量的に一致した.またセンサ粒子による加速度測定により,定性的な流体力変化の傾向が得られた.本実験結果から,流体中の固体衝突に伴う流体力学的効果の詳細が明らかとなった.
  日本学術振興会, 若手研究(B), 15760115
• Study of Fluidization of Cohesive Powder by Mechanical Vibration
  Grants-in-Aid for Scientific Research
  1999 - 2000
  TOMITA Yuji; HARADA Syusaku
  Experimental and numerical studies of spouting of powder from vertically vibrated bed are performed. The powder, especially fine and cohesive one, spouts out vigorously through a side orifice of the vertically vibrated vessel in which the powder is contained, provided that the vibration intensity is greater than unity. We examine the mechanism of this phenomenon and the relationship between the efflux rate and the vibration condition. The interstitial air pressure in the bed that periodically fluctuates is measured and is compared to the results of the numerical analysis considering the relative motion of the powder bed to the vibrated vessel and percolation air flow. The outflow behavior of powder is observed by using a high-speed video camera. The experimental and the numerical results indicate that the powder spouts out with periodic air outflow, which is generated in response to the change of the gap between the bed and the vessel base. Furthermore, it is found that the efflux rate of powder is in proportion to the generated air pressure and in inverse proportion to the vibration frequency.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Kyushu Institute of Technology, 11650180

• 粒子の分離方法および粒子の分離装置
  Patent right
  特願2024–065375, Apr. 2024
• 粉粒体供給用フィーダおよびその供給システム
  Patent right
  特開2002-19967