Influence of Finite Width of Shock Generator on Shock-Wave/Boundary-Layer Interaction

The influence of a finite-width shock generator on the incident shock in the impinging shock-wave/boundary-layer interaction is investigated using different widths of the shock generator. The shock-wave generator widths are kept at 80, 50, and 20% of the total width of the bottom wall. Ahighly three-dimensional incident oblique shockwave is observed. Experimental and numerical studies are used to understand the nature of three-dimensional shock downstream of the leading edge of the shock generator. The incident shock curved downstream in the streamwise and spanwise directions, and the curvature increased with the decreasing width of the shock generator. The local strength of the incident shock at the bottom wall varied significantly due to this curvature for each of the cases. Consequently, even for shock generators with the same flow deflection, the shock-wave/boundary-layer interaction nature transitioned from separated to unseparated. An explanation and a model for the three-dimensionality of the incident shock are presented, and numerical simulations validate the model. The model shows that the shape of the incident shock is a function of the freestream Mach number, the flow deflection angle, and the width of the shock generator.