2000 Fiscal Year Final Research Report Summary
Hybrid Modeling for Comelation of Velocity-Pressure Fluctuation
| Project/Area Number |
11650190
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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 |
Fluid engineering
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| Research Institution | Keio University |
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Principal Investigator |
OBI Shinnosuke Keio University, Department of Mechanical Engineering, Associate Professor, 理工学部, 助教授 (80233609)
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| Co-Investigator(Kenkyū-buntansha) |
MASUDA Shigeaki Keio University, Department of Mechanical Engineering, Professor, 理工学部, 教授 (90051664)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Turbulent diffusion / Pressure diffusion / PIV measurement / Hybrid modeling / Poisson equation of pressure / Turbulence modeling |
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| Research Abstract |
Attempts have been made for the development of a phenomenological turbulence modeling of turbulent transport process related to pressure fluctuation. The project is divided into two parts, i.e., experimental approach and numerical simulation. The former is consisted of the velocity measurement by a PIV and the successive evaluation of discrete Poisson equation of pressure using the velocity field data obtained by the measurements. The latter part has been conducted under the equivalent condition as the experiment, and the results support detailed information to properly interpolate the experimental information.
The turbulent wake of a rectangular cylinder at Reynolds number of 1,000 has been chosen for the test case. The velocity measurements are conducted at the center plane of the span. The instantaneous pressure distribution obtained from the numerical solution of Poisson equation based the measured velocity data has used to interpret the associate physics, i.e., the dynamics and vor
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tex and pressure field. It has been shown that the so-called pressure diffusion term appearing in the transport equation of turbulent kinetic energy has an opposite effect against the turbulent diffusion that is consisted of the triple moment of fluctuating velocity, and the analogy between these two effects is not supported in the entire region, which is in contradiction to the common belief.
The results of numerical simulation conducted in the framework of the present study suffered a certain extent of numerical error, though it is suggested that the large-scale vortex motion immediately behind the rectangular cylinder is well represented by the velocity-pressure correlation term that has been ignored in the framework of RANS modeling. In accordance to the experimental part, the pressure diffusion transport of turbulent kinetic energy is partly aligned to its counterpart caused by turbulent diffusion, though these two processes do not show a simple analogy, hence they should be modeled separately. Less
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