A Universal Scaling Law for Jets of Collapsing Bubbles

TL;DR

This paper discovers a universal scaling law for vapor jets in collapsing bubbles under pressure gradients, showing the jet volume depends on a specific dimensionless parameter and is independent of liquid properties.

Contribution

It introduces a new universal scaling law for vapor jets in collapsing bubbles, validated by experiments and theoretical derivation, with minimal influence from surface tension.

Findings

Normalized jet volume is independent of liquid density and viscosity.

Jet volume is proportional to the parameter zeta=grad(p)*R0/p.

Jet pierces the bubble boundary only if zeta>0.0004.

Abstract

Cavitation bubbles collapsing and rebounding in a pressure gradient grad(p) form a "micro-jet" enveloped by a "vapor jet". This letter presents unprecedented observations of the vapor jets formed in a uniform gravity-induced grad(p), modulated aboard parabolic flights. The data uncovers that the normalized jet volume is independent of the liquid density and viscosity and proportional to zeta=grad(p)*R0/p, where R0 is the maximal bubble radius and p is the driving pressure. A derivation inspired by "Kelvin-Blake" considerations confirms this law and reveals its negligible dependence of surface tension. We further conjecture that the jet only pierces the bubble boundary if zeta>0.0004.