Evolution of the fine structure of the pattern of the distribution of a substance of the free-fall droplet in mixing liquids

The evolution of the pattern of the substance of a drop of ink falling freely into quiet water in the mode of formation of a cumulative back jet stream was traced by high-speed video recording. In the phase of primary contact and coalescence, the pigment of the drops merging with the targeted fluid is distributed in the form of fine fibers (ligaments), which form a regular striped pattern on the surface of the growing crown, and a net pattern consisting of three-, four- and pentagonal cells at the bottom of the cavity. The fibrous distributions of the substance droplets was saved at all subsequent stages of the evolution of the flow until the formation of a cascade of vortices, after which the picture is blurred by the processes of molecular diffusion in a practically quiescent liquid. The formation of a discrete (fibrous) pattern of the distribution of the substance of a drop is associated with the compactness of the region of release of the available potential surface energy during the confluence of liquids, which initiates a fast movement of a thin layer. Subsequent preservation of fibers ensures the slowness of molecular diffusion processes.