Multiple Emissions of Splashes upon Drop Impact

Abstract

For the first time, photo and video detection is carried out for all groups of small droplets (splashes) emitted when a drop of $0.2 < D < 0.5$ cm in diameter falls with a velocity of $1 < U < 4.05$ m/s into a pool with water. In the splash-formation mode, groups of droplets are ejected in echelons first from the tops of spikes on the veil around the primary contact area, then, from the spikes on the edges of the split shells of the crown, and, finally, from the teeth of its chevron. The first splashes fly out radially, and the next move inward around the cavity and vertically upward. The splash sizes grow with time from 0.1 to 1.0 mm. Their velocities decrease from 20 to 1 m/s, and the intervals between groups increase from 50 μs to 2.5 ms until the beginning of smoothing of the crown teeth ($t \approx 17$ ms). The acceleration of the droplets is facilitated by the conversion of the available potential energy when the free surfaces of the merging droplets are annihilated.