Shock structures and post-impact jetting in hypervelocity droplet impingement

Abstract

The shock dynamics resulting from high-speed droplet impingement on a rigid surface are investigated employing high-resolution schlieren imaging and numerical simulations based on the five-equation model. A key finding is that, in contrast to the common emphasis on jetting-induced dynamics, the long-time shock morphology is governed not by explosive shocks generated during jetting, but rather by the reflection of the droplet’s own shock wave off the solid wall. The resulting shock structure is found to be robust across a wide range of densities and breakup states, and its evolution is shown to depend primarily on the impact Mach number. Axisymmetric and 3D simulations both capture the wall-reflected envelope with high fidelity, despite shared limitations in modeling post-impact jetting dynamics. The presented results clarify the physical mechanisms shaping post-impingement shock evolution and highlight the modeling trade-offs involved in capturing jet-driven transients. This paper provides a unique experimental and numerical dataset that can be used as a reference for future studies.