Aerodynamics of recirculating flow control devices for normal shock/boundary-layer interactions

Passive methods of controlling shock/boundary-layer interactions (SBLIs) consist of a porous surface covering a cavity or a plenum located in the region of the SBLI. The present study focuses on the flowfield downstream of a Mach 1.42 SBLI controlled with various passive devices such as a conventional porous plate, a microporous plate, streamwise slots, a conventional mesoflap array, and a hybrid flap array. Qualitative analysis of the flowfield for the various control devices investigated was achieved with spark shadowgraph visualizations and surface oilflow visualizations. Quantitative analysis was accomplished by measuring surface static pressure distributions and boundary layer velocity profiles. The flow-fields downstream of the slot-controlled and hybrid flap array-controlled SBLIs were found to be highly three-dimensional, whereas the flowfields were predominantly two-dimensional for the remainder of the control devices. It was found that only the conventional mesoflap array had an improved total pressure recovery compared to the baseline solid wall.