2017 Fiscal Year Final Research Report
Optimization of three-dimensional riblet by means of high-resolution dual-plane stereoscopic PIV and large-scale DNS
| Project/Area Number |
15K05785
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Fluid engineering
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| Research Institution | Tokyo University of Agriculture and Technology |
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Principal Investigator |
IWAMOTO Kaoru 東京農工大学, 工学(系)研究科(研究院), 教授 (50408712)
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| Project Period (FY) |
2015-04-01 – 2018-03-31
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| Keywords | リブレット / 乱流 / 抵抗低減効果 / 直接数値計算 / ＰＩＶ |
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| Outline of Final Research Achievements |
Direct numerical simulations and laboratory experiments of a turbulent channel flow with an innovative three-dimensional riblet were performed, of which the lateral spacing of the adjacent walls is sinusoidally varied in the streamwise direction. A largest drag-reduction rate of about 12% is obtained by means of parametric studies. The present riblet respectively induces a downward and upward flows in the expanded and contracted regions, resulting in the decrease of the Reynolds shear stress. Vortical structures in the vicinity of the riblets were advected along the induced flow, and the vortices were deteriorated. As a result, the region of the high wall shear stress in the enlarged part of the riblet is localized. Consequently, a high drag reduction effect can be obtained.
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| Free Research Field |
熱流体工学
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