Fluid Ablation Interactions on a Compression Ramp at Mach 8

Abstract

Direct numerical simulations (DNS) are performed over a 15°compression ramp undergoing ablation at Mach 8 to examine fluid-ablation interactions (FAI) on transitional high-speed boundary layers. The experiments at these conditions with a rigid wall are first numerically replicated for a laminar flow. Heating streaks are introduced by introducing perturbations in the baseflow informed by prior stability calculations. The ramp is then replaced by a low-temperature ablator in our DNS and the interaction of the streaks with the recessing ablator surface are examined. Different approaches from two independently developed solvers are used to study this problem. Overall, both solvers provide qualitatively and quantitatively very similar results; however, differences in streak amplification and mass blowing magnitudes are observed. We discuss the difficulties in accurately predicting ablation and present the first findings regarding its influence on the perturbation evolution and transition to turbulence for this configuration.