| Project/Area Number |
09640476
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
物理学一般
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| Research Institution | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
KAMBE Tsutomu GRADUATE SCHOOL OF SCIENCE, THE UNIVERSITY OF TOKYO, PROFESSOR, 大学院・理学系研究科, 教授 (60013679)
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| Co-Investigator(Kenkyū-buntansha) |
UMEKI Makoto GRADUATE SCHOOL OF SCIENCE, THE UNIVERSITY OF TOKYO, RESEARCH ASSOCIATE, 大学院・理学系研究科, 助手 (40221808)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1999: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1997: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | scattered waves / shock waves / vortex ring / diffracted waves / statistical laws of turbulence / 回折波 / 乱流場 / 渦構造 / 渦運動 / 波動 / 直接数値シミュレーション / 高速流 |
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| Research Abstract |
The purpose of this research is to study the interaction between vortex motions and waves and to study the vortical structure in turbulence. In our experiment, strong isolated vortices are generated in air and water, and their shapes and motions are observed. The scattered waves are measured acoustically and optically. In regard with theoretical aspects, statistical laws of the velocity field due to vortices in turbulence are analyzed by a new model. The relation between the statistical law and the vortex structure is explored by using the data of numerical simulations.
The scattered sound waves generated by the interaction between vortex rings and shock waves are investigated. The scattered waves are observed and measured. The mechanism of noise generation is considered. The scatternig theory of sound by vortex is applied to the problem of the interaction of the vortex ring and shock waves.
Using the experimental apparatus of turbulence generation made last year, we detect the pressure field due to the vortices as a fine structure in turbulence by the pressure detector on the wall of the container. We received the pressure signal by the fine vortices generated spontaneously in turbulence.
The statistical law in turbulence is studied by the assemble of the Burgurs vortices, i.e. the vortices under the deformation by the strain field. The PDF of the velocity difference between two points is obtained and the scaling laws of the n-th moment of the velocity difference are explored. It is shown that the obtained second and third moments and the energy dissipation rate satisfy the Kolmogorov's four-fifth law. The higher-order scaling exponents of the structure functions are also obtained.
The interaction between vortex and water waves in two dimensions is studied in the case that the Born approximation does not hold. The incident dislocated and scattered waves are computed.
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