Asymmetric droplet splashing

The ideal droplet impact, i.e., the orthogonal impact on a smooth surface, results in the formation of an axisymmetric lamella followed by various symmetry-breaking instabilities. Impacts found in nature are nonideal, i.e., are affected by symmetry-breaking factors, e.g., surface topography, surface elasticity, impact nonorthogonality, etc. This work is focused on oblique impacts. The lamella retains a nearly circular shape during the early stages of such impacts, showing a weak effect of the inclination angle. A strong effect is observed during splashing which occurs at different locations along the lamella edge. The variations of the location of the border between the splash and no-splash zones as a function of the relevant parameters were determined. New features of the splashing referred to as abnormal splashing were observed at reduced ambient pressures. It is shown that the abnormal splashing is a direct consequence of the nonmonotonic variations of the threshold pressure as a function of the Weber number for orthogonal impacts. A simple model being able to capture the basic features of the splash process was proposed and validated through comparisons with the experimental results.