TRANSFER OF A DROP MATERIAL DURING THE PRIMARY CAVERN FORMATION

The transfer of a freely falling drop matter in the bulk of a target fluid at rest at the stage of primary cavity formation was traced by high-speed video recording for the first time. In the experiments, drops of water, ink solution (diluted in a ratio of 1:100) or a saturated solution of baking soda with a diameter of D = 0.43 cm fell with velocity of U = 3.1 m/s into fresh water or a 20% ammonium thiocyanate solution in the splash formation mode. In all experiments, the wall of the growing cavity was penetrated by thin fibers containing drop matter, which form an intermediate fine-structured layer. After the end of the fiber growth stage with a duration of 7–8 ms, the diffusion smoothed the concentration gradients, a liquid shell of intermediate density with a thickness of 1.5 to 0.7 mm was formed around the growing cavity. The shell is separated by a sharp boundary from the target fluid. A new group of inclined fibrous loops was formed in the wake of the collapsing cavity.