| Project/Area Number |
60460049
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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 |
気象・海洋・陸水学
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
MITSUYASU Hisashi Professor of Kyushu University, 応用力学研究所, 教授 (30038533)
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| Co-Investigator(Kenkyū-buntansha) |
MASUDA Akira Research Associate of Kyushu University, 応用力学研究所, 助手 (60091401)
KUSABA Tadao Research Associate of Kyushu University, 応用力学研究所, 助手 (00037871)
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| Project Period (FY) |
1985 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1987: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1986: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1985: ¥3,700,000 (Direct Cost: ¥3,700,000)
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| Keywords | Turbulence / Structure of air flow over wavy surface / Ind-wave interaction / wind-tunnel experiment / 波面の遮断係数 / 乱流 / 波面上の気流の構造 / 波面と気流の相互作用 |
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| Research Abstract |
A series of laboratory experiments has been made on the structure of turbulent air flow over solid wavy surfaces to clarify the growth mechanism of wind waves. Important results of the experiments are summerized as follows;
1. Outer boundary of the organized motion of the turbulent air flow over wavy surface is not much different from that over flat surface.
2. Although vertical velocity profile over wavy surface depends on the phase of the waves, the profile averaged over one wave length shows a logarithmic distribution.
3. Wave-induced velocity fluctuations U^^~,W^^~ decreases vertically as exp(-kz).
4. The pressure drag of the Stokes wave surface is larger than that of a sinusoidal wave surface. The increase is mainly due to the increase of phase shift rather than the increase in the pressure magnitude.
5. If we define the sheltering coefficient of the wavy surfaces as the ratio of the pressure drag coefficient to the square of the maximum slope of the wavy surface, it can be uniguely expressed as a function of the Reynolds number.
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