| Project/Area Number |
02452191
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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 |
土木構造
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| Research Institution | Kyoto University |
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Principal Investigator |
SHIRAISHI Naruhito Kyoto Univ., Civil Eng., Professor, 工学部, 教授 (40025903)
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| Co-Investigator(Kenkyū-buntansha) |
SHIRATO Hiromichi Kyoto Univ., Civil Eng., Research Associate, 工学部, 助手 (70150323)
MATSUMOTO Masaru Kyoto Univ., Civil Eng., Associate Professor, 工学部, 助教授 (00026270)
MITSUTA Yasushi Kyoto Univ., Disaster Prevention Res. Inst., Professor, 防災研究所, 教授 (90027219)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 1991: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1990: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Keywords | Bridge Structures / Aerodynamic vibration / Turbulent Effect / Shear Layer Instability / Vortex-Induced Oscillation / Reynolds Number Effect / Aerodynamic Stability / Atmospheric Turbulence / レインバイブレ-ション / 耐風安全性 / 気流シミュレ-ション |
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| Research Abstract |
In order to clarify the effect of flow turbulence on aerodynamic vibration phenomena for bridge structures and characteristics of atmospheric turbulence, the following items are mainly discussed during the term of project ;
(1) Generation mechanism of vortex-induced oscillation-by applied sound experiment and effect of turbulence (1990),
(2) Cable-aerodynamics and effect of turbulence (1990),
(3) Safety evaluation of bridge structures due to strong natural winds (1990),
(4) Simulation of atmospheric turbulence (1990),
(5) Turbulence effect on vortex-induced oscillation for bluff hexagonal bridge girder section (1991),
(6) Reynolds number effect on aerodynamic response of rectangular cross section with corner-cut (1991),
(7) Evaluation of surface roughness parameters (1991).
Consequently, the destabilization effects of turbulence were observed in some cases, such as vortex-induced oscillation for bluff hexagonal cross section with handrails, rain-wind induced vibration of inclined cable, and so on. Besides, it was concluded that the effect of turbulence could be explained in terms of frequency dependence of velocity fluctuation on the instability of shear layer being developed around a bluff body. Strong Influence of Reynolds number (based on the height of body) upon maximum amplitude of vortex-induced oscillation, critical wind velocity of galloping oscillation was also clarified for a bluff rectangular cross section with corner-cut. The evaluation method of surface roughness parameters as well as the equipment for field observation of natural winds were newly developed and confirmed their applicability. Safety evaluation for bridge structures, in which the properties of aerodynamic responses, natural winds are taken into account, was also proposed.
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