Size distribution of a drop undergoing breakup at moderate Weber numbers

TL;DR

This study investigates the size distribution of droplets resulting from dual-bag breakup of water drops at moderate Weber numbers, combining experimental techniques with analytical modeling to understand fragmentation patterns.

Contribution

It demonstrates that dual-bag breakup exhibits a bi-modal size distribution and validates an analytical model predicting droplet size distribution across Weber numbers.

Findings

Dual-bag breakup shows a bi-modal size distribution.

The analytical model accurately predicts droplet size distribution.

Core drop disintegration leads to larger droplets.

Abstract

The size distribution of child droplets resulting from a dual-bag fragmentation of a water drop is investigated using shadowgraphy and digital in-line holography techniques. It is observed that parent drop fragmentation contributes to the atomization of tiny child droplets, while core drop disintegration predominantly results in larger fragments. Despite the complexity associated with dual-bag fragmentation, we demonstrate that it exhibits a bi-modal size distribution. In contrast, the single-bag breakup undergoes a tri-modal size distribution. We employ the analytical model developed by Jackiw and Ashgriz (2022) for dual-bag fragmentation that convincingly predicts the experimentally observed droplet volume probability density. We also estimate the temporal evolution of child droplet production in order to quantitatively illustrate the decomposition into initial and core breakups. Furthermore, we confirm that the analytical model adequately predicts the droplet size distribution for a range of Weber numbers.