Axisymmetric study of drop interface impact in viscous flow

This work studies the effects of Reynolds number and Weber number on the rebounding phenomena in the drop/interface impact problem in a viscous flow. A drop falls through a viscous liquid and then impacts a liquid interface at the bottom. The drop may break to a ring in the falling process. In the impact, the drop may rebound or coalesce on contact. In this numerical study, we assume the drop falling and impacting processes are axisymmetric. We use axisymmetric finite element level-set method and adaptive mesh to solve the Navier-Stokes equations to simulate this process. After extensive parameter studies, we find that there is a range of Weber numbers dependent on the Reynolds numbers, within which the drop rebounds, below which the drop would coalesce directly with interface, and above which the drop may break into a ring.