The Evolution Of The Deformation And Breakup Of A Drop-in-liquid Under An Instantaneous Incoming Flow

An experimental study of deformation and breakup of a drop in ambient oil induced by an impact loading was conducted in a specially designed"drop tower"facility. The facility, which is aimed at achieving a comparable performance of a shock tube for drop-in-gas experiments, was confirmed to be very useful and has great potential for the investigation of drop deformation and breakup in liquid-liquid two-phase system. Thanks to the visualization with a high speed camera, the detailed configuration and temporal development of the drop were captured with fairly nice quality. Based on the experimental results obtained under various operational conditions, four recognizably different modes of the drop evolution have been summarized, which were respectively named'bag','cap','bamboo'and'mushroom'mode according to their shape features, and some of the modes have not been found by us from the open publications. It was also found that several parameters, such as densities of the drop and ambient oil, the interfacial tension, the initial drop diameter and the impulse etc., have significant effects on the drop evolution process. We particularly concentrated on the transitions between different modes due to the changes of the initial drop diameters and the impulse amplitudes, and the results were mapped into a H-D plane (H is the tank free-fall height and D is initial diameter of the drop). The existence of similar deformation configurations in different diameters and in different impulses was noticed from the experiments, which implies that similar deformation process may occur for different pairs of properly chosen'H'and'D'.