When bubbles burst in complex fluids

Abstract

 When a bubble bursts at a liquid surface, the collapsing cavity sends capillary waves towards its base. If the waves focus, the liquid rises as a jet and may shed droplets. What survives of this sequence when the liquid can resist yielding or remember being stretched?

I will use direct numerical simulations to follow how surface energy becomes motion and is dissipated. In a viscoplastic liquid, a jet can form even when droplet ejection is suppressed. At higher yield stress, the cavity can stop collapsing altogether, leaving a persistent crater. I will then consider how elasticity adds a material timescale to the problem. Bubble rupture is brief, but its outcome depends on whether capillary waves can focus before the liquid arrests their motion.

About the Speaker

Vatsal Sanjay is an Assistant Professor of Physics at Durham University, where he leads the Computational Multiphase Physics (CoMPhy) Lab. He uses direct numerical simulations and scaling arguments to study drops, bubbles, jets and other free-surface flows, particularly in complex fluids.

Host: Professor Ricardo Constante Amores