Flow Properties of a Supersonic Turbulent Boundary Layer with Wall Roughness

Anexperimental study ofthe ine uenceofsurfaceroughness on themean and turbulente owproperties of a highspeed (M =2:9;Re/m=2:0 ££ 10 7 ) turbulent boundary layer e ow was performed. Six wall topologies, including a smooth and e ve rough surfaces consisting of three random sand-grain plates and two uniformly machined plates (k + =100‐570), were tested. Mean e ow measurements included surveys of the velocity and density. Turbulence quantities included direct measurements of the kinematic velocity turbulence intensities, mass e ux turbulence intensities, thekinematicReynoldsshearstress,thecompressibleReynoldsshearstressandthedensity-transversevelocity e uctuation correlation. The trends in the mean e ow, observed for incompressible e ow, were found to hold forthepresentstudywhenVanDriestIIscalingwasused.Kinematicstatisticalturbulente owpropertieswerefound to scale by local mean quantities. Conversely, turbulent e ow statistical properties with an explicit thermodynamic dependence did not scale by local mean quantities and had a strong linear dependence on roughness height. Roughnesswasfound to extend theregion where inner scaling held toward larger values of y + for thecompressible Reynolds shear stress, the x- and y-velocity component turbulence intensities, the x-component of the mass e ux turbulence intensity, and the density-transverse-velocity correlation.