Numerical Simulation of Surface Patterns on Sublimating Ablative Materials

University of Minnesota Ph.D. dissertation. 2021. Major: Aerospace Engineering and Mechanics. Advisor: Graham Candler. 1 computer file (PDF); 98 pages.Thermal protection systems made of ablative materials are a well-known solution to protect vehicles from high heating environments. As the material changes shape due to the ablation process, several patterns may develop. One pattern that develops is a very regularly ordered diamond-shaped pattern known as crosshatching. The mechanism for which initiates the pattern development is not yet known. This research aims to study the ablation process and its contribution to crosshatching by implementing and validating a camphor sublimating boundary condition into the US3D fluid-solid solver. This work shows that the sublimation process can develop localized deep grooves, leading to the onset of crosshatching. The stability of a sublimating boundary layer is also not well studied. Through this work, it was demonstrated that the presence of camphor in the boundary layer is stabilizing. There are still many open questions on how the camphor presence affects a boundary layer's stability and how it could potentially play a role in the initiation of crosshatching