Higher-Order Simulations of Droplet-Shock Interaction, Aerobreakup and Impingement at High Mach Numbers

The numerical simulation of droplet impingement at high Mach numbers is a challenging problem, involving a wide range of physical mechanisms, including material and flow discontinuities, interfacial instabilities, phase change, and turbulence. Diffuse interface multiphase methods provide a simple, computationally efficient, and numerically robust approach to model these phenomena. In this work, a higher-order numerical solution procedure for the Allaire five-equation model is used within the in-house solver CHAMPS (previously validated against available numerical and experimental data) to simulate droplet aerobreakup and impingement at larger Mach numbers. The Adaptive mesh refinement allows for efficient tracking of important flow features such as gas/liquid interfaces, shocks and wakes and the target geometries are modeled using an immersed boundary method. For the droplet impingement simulations, the effects of shock standoff distance on the overall flow characteristics and surface pressure signature are investigated. A preliminary assessment of the damage incurred on the surface is evaluated employing the structural peridynamics solver Emu. It will be shown that the impact crater is highly dependent on the state of the droplet before impact.