Influence of surface roughness on the mean and turbulence flow properties of a supersonic boundary layer
Conference Paper
Overview
Overview
abstract
1999 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. An experimental study of the influence of surface roughness on the mean and turbulent flow properties of a high-speed (M = 2.9) high Reynolds number (Re/m = 1.9xl07) turbulent boundary layer flow was performed. Six wall topologies including of a smooth and five rough surfaces consisting of three random sand-grain plates (k+ = 100, 400,570) and two uniformly machined plates (k = 0.559 mm for both) were tested. A confocal laser scan microscope was used to accurately document the topography of the sand-grain plates. The experimental measurement techniques included a conventional Pitot pressure probe, laser Doppler velocimetry, hot-wire anemometry, and color schlieren photography. Mean flow measurements included profiles of velocity, Mach number and mass flux. The mean flow defects were found to scale with local mean values, and the incompressible defect law held for the present data. Turbulence measurements included profiles of velocity and mass flux turbulence intensities, kinematic Reynolds shear stress, compressible Reynolds shear stress and the traverse apparent mass flux. Kinematic turbulent flow statistical properties were found to scale by local mean quantities and displayed a weak dependence on surface roughness topography. Turbulent flow statistical properties with the explicit appearance of density did not scale by local mean quantities, and had a strong linear dependence on roughness height.
