Velocity Measurements in a Shock-Separated Free Shear Layer

Two-component laser Doppler velocimetry measurements were made in a planar, shock-separated free shear layer formed by the convergence of two supersonic streams past a thick plate. High-speed wall-pressure measurements were used to locate the unsteady shock wave formed by this interaction and, consequently, facilitated separation of the effects of shock motion from the turbulent fluctuations in the velocity measurements of the shear layer. Shock-induced flow separation dramatically increases the turbulent normal and shear stresses. The shock-separated shear layer displays a positive shear stress region between separation and reattachment. Reattachment produces a shift in turbulent kinetic energy from the streamwise component to the transverse component. The region of shock motion has a relatively constant width, irrespective of distance from the wall.