1987 Fiscal Year Final Research Report Summary
Self-Control of Boundary Layer Separation
| Project/Area Number |
61550138
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Fluid engineering
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| Research Institution | Keio University |
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Principal Investigator |
MASUDA Shigeaki Faculty of Sci. and Tech., Keio Univ., Professor, 理工学部, 教授 (90051664)
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| Co-Investigator(Kenkyū-buntansha) |
ARIGA Ichiro Faculty of Sci. and Tech., Keio Univ., Professor, 理工学部, 教授 (40051172)
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| Project Period (FY) |
1986 – 1987
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| Keywords | boundary layer control / boundary layer separation / rough surface / diffuser / percent downstream flow / 乱流 |
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| Research Abstract |
As the first step of the research project on the self-control of boundary layer separation, the turbulent separation on rough surfaces has been investigated. Attention was paid on the possible interaction of a micro cavity around a roughness element with outer large scale recirculating eddies.
The two-dimensional asymmetric diffuser has been constructed, which has only one diverging wall. The divergence angle can be varied between 0 to over 20 degrees, and the wall material can easily be interchanged. The inlet condition is the two-dimensional turbulent channel flow and the outlet is open to the atmosphere.
After preliminary examination of the basic characteristics of separation on the hydraulically smooth rigid non-porous surface, the whole surface of the diverging wall was changed to the sand-paper, honeycom, grooves and reblets. The static pressure recovery ,percent cownstream flow, time mean velocity and turbulence intensity were measured and compared with the smooth wall results. It has been revealed that the all materials except the sand-paper promote the separation.
The diverging wall downstream of the incipient detachment point was then partially covered with the rough materials. The results indicated that separation is not at all affected by the roughness on the separated surface.
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