2022 Fiscal Year Final Research Report
Study of unsteady behavior of cloud cavitation and its induced shock wave
Project/Area Number |
21K20414
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Research Category |
Grant-in-Aid for Research Activity Start-up
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Allocation Type | Multi-year Fund |
Review Section |
0301:Mechanics of materials, production engineering, design engineering, fluid engineering, thermal engineering, mechanical dynamics, robotics, aerospace engineering, marine and maritime engineering, and related fields
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Research Institution | Waseda University |
Principal Investigator |
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Project Period (FY) |
2021-08-30 – 2023-03-31
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Keywords | キャビテーションクラウド / 衝撃波 / 混相流解析 / SPH法 / PIV計測 |
Outline of Final Research Achievements |
The main purpose of this study is to understand how a cloud cavitation performs a collective unsteady motion and how a shock wave is emitted associated with the collapse of the cloud in conjunction with the multiphase flows. The results obtained from the multiphase flow analysis by the two-dimensional Smoothed Particle Hydrodynamics, the experimental observation of the cloud, and the measurement of velocity fields of the cloud by the Particle Image Velocimetry method are as follows: (1) The unsteady behavior of the cloud and its induced shock waves have been observed numerically, and compared with experimental results; (2) The flows of twin vortices around the cloud have been shown by numerical tests and experimental measurements; (3) The multi-shock wave phenomena associated with the collapse of the cloud have been numerically suggested.
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Free Research Field |
混相流
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Academic Significance and Societal Importance of the Research Achievements |
クラウドの圧壊に伴う衝撃波現象は流体機械における壊食や騒音の原因になる一方で,近年では医療や環境の分野での工学的応用が盛んである.ゆえに,クラウドの非定常挙動と衝撃波現象のメカニズムの解明と数学モデルの提案が重要な課題であるが,高速かつ微小な現象であり,さらに相変化を伴う複雑な流れであるため,実験的な観測や数値解析による再現が難しいものとなっている.そうした中で,本研究は実験と数値解析の両面から調査し,得られた研究成果は混相流の流れ場の観点からの現象のモデリングの提案,及びクラウドから放出される強力な衝撃波の形成メカニズムの説明に繋がるものであり,学術的・社会的に意義があると確信している.
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