Laser Doppler anemometer measurements of turbulent boundary layer over a riblet surface

AIAA Journal ◽  
1996 ◽  
Vol 34 (5) ◽  
pp. 1007-1012 ◽  
Author(s):  
L. Djenidi ◽  
R. A. Antonia
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Laser Doppler Anemometer ◽  
Laser Doppler ◽  
Riblet Surface

scholarly journals Evaluation of Skin Friction Drag Reduction in the Turbulent Boundary Layer Using Riblets

2019 ◽  
Vol 9 (23) ◽  
pp. 5199
Author(s):  
Hidemi Takahashi ◽  
Hidetoshi Iijima ◽  
Mitsuru Kurita ◽  
Seigo Koga
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Skin Friction ◽  
Three Dimensional ◽  
Hot Wire ◽  
Friction Drag ◽  
Freestream Velocity ◽  
Turbulent Statistics ◽  
Friction Drag Reduction ◽  
Riblet Surface

A unique approach to evaluate the reduction of skin friction drag by riblets was applied to boundary layer profiles measured in wind tunnel experiments. The proposed approach emphasized the turbulent scales based on hot-wire anemometry data obtained at a sampling frequency of 20 kHz in the turbulent boundary layer to evaluate the skin friction drag reduction. Three-dimensional riblet surfaces were fabricated using aviation paint and were applied to a flat-plate model surface. The turbulent statistics, such as the turbulent scales and intensities, in the boundary layer were identified based on the freestream velocity data obtained from the hot-wire anemometry. Those turbulent statistics obtained for the riblet surface were compared to those obtained for a smooth flat plate without riblets. Results indicated that the riblet surface increased the integral scales and decreased the turbulence intensity, which indicated that the turbulent structure became favorable for reducing skin friction drag. The proposed method showed that the current three-dimensional riblet surface reduced skin friction drag by about 2.8% at a chord length of 67% downstream of the model’s leading edge and at a freestream velocity of 41.7 m/s (Mach 0.12). This result is consistent with that obtained by the momentum integration method based on the pitot-rake measurement, which provided a reference dataset of the boundary layer profile.

scholarly journals Effect of drag reducing riblet surface on coherent structure in turbulent boundary layer

2019 ◽  
Vol 32 (11) ◽  
pp. 2433-2442 ◽  
Author(s):  
Guangyao CUI ◽  
Chong PAN ◽  
Di WU ◽  
Qingqing YE ◽  
Jinjun WANG
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Coherent Structure ◽  
Riblet Surface
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