Surface roughness effects on a Mach 6 turbulent boundary layer
The effect of a two-dimensional square bar roughness on the equilibrium Mach 6 turbulent boundary layer has been experimentally investigated. A modified Van Driest transformation and the incompressible form of the law-of-the-wall have been used to evaluate the surface roughness effects. Comparison of the results with previously published data reveals that current methods of predicting roughness effects for compressible flows fail in this case. When the rough wall skin friction ratio and velocity defect are considered as functions of the equivalent sand-grain roughness, however, correlations which are valid for both compressible and incompressible flows result. While these correlations reduce the problem of determining roughness effects to one of determining the equivalent sand-grain roughness, the present data emphasize that low-speed correlations for effective sand-grain roughness cannot be arbitrarily applied to compressible data.
- Research Organization:
- Sandia Labs., Albuquerque, N.Mex. (USA)
- DOE Contract Number:
- EY-76-C-04-0789
- OSTI ID:
- 6793960
- Report Number(s):
- SAND-78-0027C; CONF-780711-1
- Country of Publication:
- United States
- Language:
- English
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