2000 Fiscal Year Final Research Report Summary
Analysis of Dynamics of the Cloud Cavitation and its Control
| Project/Area Number |
11450071
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fluid engineering
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MATSUMOTO Yoichiro The University of Tokyo, Graduate School of Engineering, Professor, 大学院・工学系研究科, 教授 (60111473)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Hajime The University of Tokyo, Graduate School of Engineering, Professor, 大学院・工学系研究科, 教授 (20166622)
KATO Hiroharu Toyo University, Faculty of Engineering, Professor, 工学部, 教授 (00010695)
TAMURA Yoshiaki The University of Tokyo, Intelligent Modeling Laboratory, Associate Professor, インテリジェント・モデリング・ラボラトリー, 助教授 (40217203)
SUGIYAMA Kazuyasu The University of Tokyo, Graduate School of Engineering, Associate Researcher, インテリジェント・モデリング・ラボラトリー, 研究員
ICHIKAWA Yasumasa The University of Tokyo, Graduate School of Engineering, Associate Professor, 大学院・工学系研究科, 助手 (40134473)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Erosion / Cavitation / Hydrofoil / Numerical / Lift Coefficient / Drag Coefficient / Void Fraction / Pressure Distribution |
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| Research Abstract |
It is well known that a cloud cavitation is one of the most destructive forms of cavitation. In the present study, the set of equations for the motion of a spherical bubble cloud is formulated and the behavior of bubble clouds are simulated numerically under the situation of sudden change of surrounding pressure. To study the collapse of cloud cavitation more accurately, the internal phenomena of each bubble and the compressibility of liquid are considered in the governing equations. An inward propagating shock wave is formed during the collapse of bubble cloud and the shock wave is focused in the center region of the cloud. This makes a violent bubble collapse, which cause a high emitted pressure from the bubbles, which is several hundreds times larger than the single bubble collapse. Furthermore, a new numerical method for simulating cavitating flows around hydrofoil is developed. Cloud cavitation is modeled with perfectly spherical bubbles whose radii change with Rayleigh-Plesset equation. The bubbles are also allowed to have slip velocities so that the bubble accumulation could be simulated. Psedocompressibility concept for incompressible flow simulation is extended for the present systems of equations for efficient and robust computations. Computations of two-and three-dimensional cavitating flows verify the present method and show its capability to the practical applications.
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