Droplet impact on liquid pool: secondary droplets formation from Rayleigh jet breakup and crown splash

Abstract

The study of droplet interaction with liquid films has immense importance in the cleaning of oil spills. India sits on one of the busiest sea trade routes in the world, almost the entire oil supply to south-east Asian countries and China happens through Indian waters. Although this has benefitted India economically, the oil spill accidents have caused massive damage to the ocean ecosystem. The recent Ennore oil spill that occurred near the shores of Chennai, Tamil Nādu is one of such case where a huge loss of aquatic life has been observed due to oil spilling in seawater. In this work, we are trying to understand impact of low-density droplets on high-density fluid pools. The setup for the experiment involves a high-speed camera collecting images of the droplet impacting on the pool, image processing yields images describing the state of the interface at every timestamp. We observed that the density and viscosity of the fluids play a crucial role on the post-impact behavior. At a high Weber number, the probability of a Rayleigh jet breakup increases. However if the viscosity of the pool liquid is higher than the droplet, in that case penetration of the interface becomes difficult and the probability of a crown splash increases, in such cases the probability of obtaining a crown splash increases as the Weber number increases. At a high Ohnesorge number, no jet eruption is observed and if in such a case the Weber number is increased then the crown splash phenomenon becomes more prominent to occur.