High-fidelity Numerical Simulations of High-speed Droplet Impact on Deformable Solids

The high-speed impact of droplets on solid surfaces is key phenomenon in various applications, including scenarios such as fuel injection during rapid combustion, aircraft interactions with rain droplets, wind turbine blade erosion due to rain impact, and jet engines ingesting water droplets that strike compressor blades. However, capturing the dynamics of multiphase flows at high speeds (transonic to hypersonic) through experimental methods can be challenging. Here, we present a capability for Eulerian high-fidelity numerical simulations (with fifth-order spatial and third-order temporal accuracy) to model high-speed droplet impact, deformation, and damage of solid materials. A combination of sharp and diffuse interface methods is employed to simulate the dynamics of liquid, air, and solid materials. We study the loading characteristics of a water droplet hitting the solid plate at high impact speeds (ranging from 100s to 1000s of meters/sec). Such high-speed impact induces shockwaves in the droplet as well as in the solid material, with the droplets exhibiting cavitation and shear-stripping and structural-damage propagation (in solids). The extreme droplet simulation including phase transition is modeled using a diffuse interface approach. Through the high-fidelity numerical simulations, we discuss the evolution of spatiotemporal features of the droplet impact, force, shear-stress distributions, and the corresponding damage on solid surfaces in the early- and late-impact regimes.