Dual cavity dynamics in deep water

The dynamics of the simultaneous impact of liquid drops on a deep liquid is studied experimentally using high-speed imaging and particle image velocimetry techniques. We experimentally investigated the effect of the distance between the two liquid drops on fully developed splashing. For a given Weber number, we observe key characteristics of dual splashing, including crown jets, central lamella, merging craters and jets, and straight and tilted jets, as the distance between the drops varies. When the distance between the impacting drops is less than the drop diameter, instabilities propagate at the interface between the dual craters, causing them to merge into a single crater. Furthermore, the inner walls of the crowns interact and form a thick central sheet, which suppresses or delays the wavefronts on the inner walls of the craters. This effect causes the asymmetric retraction of the craters. The merging of craters into a single crater and the asymmetric retraction of the craters cause a delay in the craters’ retraction. The retraction of the craters is a major factor determining whether the jets are straight or inclined. The straight jets are ejected when the retraction of the craters is axisymmetric, and the inclined jets are ejected when the retraction of the craters is asymmetric.