Ablation onset in unsteady hypersonic flow about nose tip with cavity

A forward-facing cavity is examined as a means of reducing the severe heating and ablation at the nose tip of a hypersonic vehicle. Whereas previous studies have concentrated on heating rates alone, the present study addresses the effects of the cavity on ablation onset times through experiments and joined flowfield/heat conduction simulations. A viable experimental technique has been developed to study ablation in the Mach 5 wind tunnel at the University of Texas at Austin J.J. Pickle Research Center. Using this technique, the time to ablation onset for a nonoptimized, rounded-lip, deep-cavity model has been found to be similar to that of the baseline hemisphere-cylinder model. Additionally, the computational technique predicts ablation onset times that agree surprisingly well with the Mach 5 experimental data. Thus, a benchmark is achieved in the computational techniques for future use for determining the experimental flowfield physics of this complex, unsteady hypersonic Row problem.