Upstream Influence in Shock Wave/Transitional Boundary Layer Interactions at Mach 1.8

This work expands on previous efforts that observed high-intensity resonance in the dynamic shock motion generated by shock wave/boundary layer interactions with Mach 1.8 edge conditions when the inflow boundary layer is in transition. Specifically, this effort characterizes the behavior of a thickening of the boundary layer upstream of the separation shock location that appears to strongly correlate with the motion of the upstream influence shock; this work also verifies that the focused spectra observed in measurements with a cylinder on a flat plate are also observed in interactions generated by a blunt fin or on a cone with similar boundary layer edge conditions. The dynamic motion of the shock waves in the transitional interactions are characterized using high-speed schlieren and statistical information derived by tracking the location of various features of the interaction within the frame sequence.