A comprehensive experimental and computational study has been completed on the shock detachment process in nonequilibrium hypervelocity flows over cones.

This project extends previous studies which showed the growth rate or the detachment distance with increasing cone half ngle is smaller for nonequilibrium than for frozen of equilibrium flows. This effect is related to the behavior of the sonic surface. Previous studies, however, were only marginally conclusive because of the relatively large measurement uncertainties. With a larger parameter range, better instrumentation and computational tools, the presenet study has been able to yield conclusive results.

A total of 24 models were tested in about 170 shots of Caltech's hypervelocity reflected shock tunnel, T5. We compared experimental and computed heat fluxes, surface pressure values, and holographic interferograms.

Starting from a scaling argument, we were able to explain the different behavior of the shock detachment growth as a function of the cone angle in nonequilibrium flows as compared to frozen or equilibrium flows. We are also able to understand the behavior of the detachment distance for the same angle as we vary the degree of nonequilibrium.