Flow Similarity in Compressible Convex-Corner Flows

Boundary-layer flow in the vicinity of a sharp corner was investigated. A scaling parameter to characterize the transition from subsonic to transonic expansion flows, incipient shock-induced boundary-layer separation, and separation length was proposed. It was found that the flow expansion near the corner apex and peak pressure fluctuations in the recompression process could be scaled linearly with similarity parameter β(<13) for subsonic expansion flows and initial transonic expansion flows. Once the local Mach number exceeded the critical Mach number, the increment of (mean surface static pressure = freestream static pressure) min with similarity parameter (≊13-20) became less significant. For the test cases of extensive shock-induced boundary-layer separation, the highly intermittent wall-pressure signals due to shock excursion phenomena resulted in intense pressure fluctuations in the recompression process.