Evaluation of Droplet Aerodynamic Breakup Models in Supersonic and Hypersonic Flows

Precipitation and suspended droplets in the atmosphere present a significant erosion risk to vehicles traveling and high-supersonic and hypersonic speeds. Here we lay the foundation for simulations of such phenomena by exploring and comparing common models for droplet drag and breakup. We test these models in a simulation of a sharp 10-degree wedge traveling at Mach 3. Understanding and properly modeling the interplay between the drag and breakup models will be critical to characterizing potential impact events by the size, quantity, location, and incidence angle of the droplets. We find the KHRT breakup model used in conjunction with an empirical drag model that accounts for the effects of droplet deformation to provide physically-reasonable droplet behavior; however, additional experimental data will be required to fully evaluate this model and to tailor model parameters for high-Mach number, high-Weber-number flows.