Investigation of regimes and associated flow structures during impingement of a liquid drop on a liquid pool

Abstract

We study the impingement of a liquid drop on a liquid pool and find four new flow structures: (i) blob, (ii) blob and secondary ring, (iii) primary ring, secondary ring and jet, and (iv) primary ring and jet. We have delineated comprehensive pictures of coalescence and splashing regimes and their associated flow structures as a function of the controlling dimensionless numbers in a series of phase diagrams. These findings may not only provide physical insight into phenomena associated with the drop impact dynamics but also assist researchers to identify the specific impact conditions under which each phenomenon occurs, so that it can be avoided or allowed depending on the application.