| Project/Area Number |
12650481
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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 |
構造工学・地震工学
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| Research Institution | MIYAZAKI UNIVERSITY |
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Principal Investigator |
OZONO S Miyazaki Univ., Applied Physics, Associate Prof., 工学部, 助教授 (10169302)
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| Co-Investigator(Kenkyū-buntansha) |
HIRATA Katsuya Doshisha Univ., Mechanical Engineering, Associate Prof., 工学部, 助教授 (40199063)
MIYAGI Hiromori Miyazaki Univ., Applied Physics, Research Associate, 工学部, 助手 (90219741)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2001: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2000: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Multi-fan type wind tunnel / Atmospheric boundary layer / Active control / Quasi-grid method / PIV / Staggered arrangement / 応答特性 / 等方性 / ゲイン修正法 / 線形せん断流 / 角柱 / 辺長比 / 背圧 / ストローハル数 / 静止実験 |
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| Research Abstract |
The goal of the present study is to make clear the aerodynamics of cylinder-like structure placed in the atmospheric boundary layer. A quasi-grid method where activated and inactivated fans are grid-like distributed. The frequency range has been restricted to a lower range, but here it was extended to a wider range reaching inertial subrange. The relationship between skewness and intermittent fluctuations was examined. The turbulence due to the quasi-grid method can be regarded as a standard, when compared with other turbulent flows created using the multi-fan type wind tunnel.
To establish a method simulating the atmospheric boundary layer, a series of experiments were conducted using the multi-fan type wind tunnel. Combining roughness and a flat plate, a boundary layer was created as a target. The uniformly-active method reproduces a mean velocity profile, but the intensity profile obtained is distinctly different from the target. A combination of the uniformly-active method and roughness improves the characteristics. In the boundary layer produced by the uniformly-active method, measurements show a small value of Reynolds stress compared with the real boundary layer. The boundary layer due to the uniformly-active method is lacking in vortical structures, thus deserving further study.
Two circular cylinders in staggered arrangement in cross-flow were taken and examined via. PIV. As the downstream cylinder was traversed along the wake, when reaching a certain gap, a critical fall in base suction was observed.
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