On the physics of transient ejection from bubble bursting

TL;DR

This paper develops a comprehensive dynamical model for transient droplet ejection during bubble bursting, revealing the role of vortex rings and providing a universal expression for droplet size and speed across various fluid conditions.

Contribution

It introduces the first single, universally valid expression for droplet ejection parameters during bubble bursting, incorporating vortex dynamics and scaling laws.

Findings

Derived a unified model for droplet size and velocity

Identified the role of vortex rings in ejection dynamics

Explained flow variable evolution and critical conditions

Abstract

The transient ejection due to a bubble bursting at the interface of a liquid with a gas environment is here described using a dynamical scaling analysis along the process. We show here that the ejection of a liquid microjet requires the backfire of a vortex ring inside the liquid to preserve physical symmetry, which involves a non-trivial scaling. We present the first single uniformly valid expression for the size and speed of ejected droplets for the whole range of the Ohnesorge and Bond numbers where droplet ejection occurs. The evolution of the flow variables, the apparent singularity for a critical Ohnesorge number, and the dispersion of data around this point are explained. Our model generalizes or displaces other recently proposed ones, impacting for instance the statistical description of sea spray.