An experimental study on the secondary droplets production during the drop impingement onto a liquid film

Experiments were performed to explore the conditions for the onset of secondary droplet formation during single drop impact onto a liquid film(splashing). It was found that there were two types of splashing: the prompt splash and the late splash. In the prompt splash, small droplets were scattered with high velocity immediately after the impact. Whilst, in the late splash, larger droplets of lower velocity were produced after the development of liquid crown. The condition for the onset of splashing was expressed using the two dimensionless numbers: the Weber number, the Ohnesorge number. The correlations were given separately for the prompt and late splashes. Moreover new correlations were developed about prediction of the secondary droplet diameter and velocity.