Experimental investigation of normal-shock/turbulent-boundary-layer interactions with and without mass removal

Interactions of a normal shock with a turbulent boundary layer over a flat surface were investigated with and without imposing mass removal. The approach flow was very nearly two-dimensional, with a uniform freestream Mach number of 1.48, strong enough to cause separation at the shock foot. Suction was imposed immediately upstream of the shock over a finely perforated surface, removing much of the boundary-layer flow. The time-mean wall pressure distributions and two components of the time-mean velocity vector field were determined for both cases. Mass removal distorted the original shock pattern and eliminated the separation at the shock foot while reducing the boundary-layer thicknesses and growth rates to less than half. Mass removal also introduced some undesirable effects: asymmetric sidewall boundary-layer growth in the subsonic flow and increased shock oscillation amplitudes. The removed mass flow varied strongly in the streamwise direction in a manner that indicated wide variations of the flow coefficients for the individual perforations.