Passive shock-wave/boundary-layer control on a wall-mounted model

Tests were made on a roof-mounted 6%-thick part section circular are model in a small transonic tunnel at transonic Mach numbers to evaluate the effects of the orientation of the orientation of holes on the passive shock-wave/boundary-layer control. Three hole orientations were investigated; normal, forward-facing and backward-facing. The porosity was 1.6%. The measurements included static and dynamic pressures on the model's surface, wake tranverses, and shadowgraphs. The forward-facing holes located around the shock position show an appreciable decrease in drag when compared with a solid surface model.