EFFECT OF RIBLETS ON TURBULENCE IN THE WAKE OF AN AIRFOIL
Measurements were made in the near and intermediate wake regions of a NACA 0012 airfoil with three different riblet sizes at a freestream Reynolds number of 2.5 x 105. The riblets tested were a symmetric v-groove type of heights 0.0229, 0.076, and 0.152 mm, respectively. To ensure turbulent flow on the airfoil, a transition strip was applied at 10% of the chord. Wake velocity profiles and turbulence parameters were measured with a temperature compensated hot-film x-probe. Riblet effectiveness was indicated by marked decrease in turbulence levels in the wake. Integration of the wake mean velocity profiles indicated a net reduction in drag of up to 13.3%, which was possibly caused by the combined effect of decreased turbulent shear stress and lower momentum exchange near the surface due to a viscosity-dominated region in the riblet valleys.
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Supplemental Notes:
- AIAA J, v 29 n 11, Nov 1991, p 1769 [2 p, 7 ref, 5 tab, 1 fig]
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Authors:
- Caram, J M
- Ahmed, A K W
- Publication Date: 1991
Language
- English
Subject/Index Terms
- TRT Terms: Airfoils; Surfaces; Turbulence; Wakes
- Old TRIS Terms: Riblets
- Subject Areas: Marine Transportation; Vehicles and Equipment;
Filing Info
- Accession Number: 00701534
- Record Type: Publication
- Source Agency: British Maritime Technology
- Files: TRIS
- Created Date: Aug 14 1995 12:00AM