Droplet rebounds off a fluid bath: kinematic match simulations and experiments

We present a method to simulate non-coalescing impacts and rebounds of droplets onto the free surface of a liquid bath, together with new experimental data. The method is derived from first principles and imposes only natural geometric and kinematic constraints on the motion of the impacting interfaces, yielding predictions for the evolution of the contact area, pressure distribution, and wave field generated by the impact on both impacting masses. This work generalises an existing kinematic-match method whose prior applications dealt with deformation in the surface of the bath only; i.e., neglecting that of the droplet. The method's extension to include droplet deformation gives predictions that compare favourably with existing experimental results and the new experiments in the low Weber number regime using submillimeter-sized droplets.