Numerical Investigation of Fluid-Ablation Interactions on a 13-Degree Straight Cone at Mach 5.3

Direct numerical simulation (DNS) of the laminar-to-turbulent transition process is performed over a low-temperature ablating, 13° semi-vertex angle straight cone at Mach 5.3 to examine fluid-ablation interaction (FAI) effects in transitional high-speed boundary layers. The flow conditions and geometry of the DNS match those of an experiment performed in which cross-hatching ablation patterns were observed. All of the simulations performed utilized the Cartesian Higher-Order Adaptive Multi-Physics Solver (CHAMPS) framework. Linear stability calculations were carried out using the Langley Stability and Transition Analysis Code (LASTRAC) to verify the DNS correctly captures the growth of the most relevant instability modes, namely, the first Mack mode. Fluid simulation data at the cone’s surface were loosely-coupled to a material response solver to obtain realistic recession, temperature, and blowing profiles. These profiles were then reapplied as a boundary condition at the cone wall for the subsequent fluid DNS and the process was iterated. Results from the four complete coupling steps show heat flux-ablation interaction patterns to be self-perpetuating and the recession topology initiated by the controlled breakdown fluid simulation undergoes amplification in time.