| Project/Area Number |
05452232
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
構造工学・地震工学
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| Research Institution | University of Tokyo |
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Principal Investigator |
FUJINO Yozo University of Tokyo, 工学部, 教授 (20111560)
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| Co-Investigator(Kenkyū-buntansha) |
TACHIBANA Hideki University of Tokyo, Institute of Industrial Science, Professor, 生産技術研究所, 教授 (80013225)
KIMURA Kichiro University of Tokyo, Graduate of School of Eng., Assistant Professor, 工学部, 講師 (50242003)
NOMURA Takashi Nihon University, College of Science and Technology, Associate Professor, 理工学部, 助教授 (50126281)
大屋 裕二 九州大学, 応用力学研究所, 助教授 (00150524)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1994: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1993: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | flow-induced noise / wind tunnel study / separation flow / edge tone / vibration control / sound / 振動制御 / 渦励振 |
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| Research Abstract |
To clarify the characteristics of the wind-induced sound from handrails of flat plate cascades, a series of wind tunnel experiments is conducted. Pure loud sound is observed when the wind is oblique to the plates. The relation between the sound frequency and the wind speed as well as the result from the flow visualization experiment suggests the cause of the sound as follows ; the flow separated from the windward edge of the plate impinges the other windward edge of the same plate, generating large pressure fluctations. It is observed that the sound frequencies increase in a step-wise manner as the increase of the wind speed, and they are shown to correspond to the resonant frequencies of acoustic oscillation of the space enclosed by the flat plate cascades. The step-wise increase of the frequencies indicates that there is a feedback between the sound generation and the acoustic resonant oscillation.
In order to investigate the possibility of suppressing flow-induced vibration of structures by applying periodic sound as well as experiments to the flow around the structures, numerical simulations of the vortex-induced vibration of a circular cylinder are carried out. A FEM based on the ALE formulation was employed to simulate the vortex-induced vibration, with the time integration being carried out by the predictor-corrector method. The experimental and numerical results revealed that the excitation with the transition wave frequency is the most effective in changing the flow characteristics around the cylinder and the characteristics of the vortex-induced vibration. These changes appear to be caused by the promotion of the vortex growth in the early vortex formation behind the cylinder.
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