Amplification of supersonic micro-jets by resonant inertial cavitation-bubble pair

TL;DR

This study experimentally and numerically investigates how resonant inertial cavitation bubbles can amplify micro-jet velocities to over 1000 m/s through a mechanism involving shock waves and bubble interaction.

Contribution

It is the first to experimentally demonstrate supersonic micro-jet amplification via cavitation bubble pairs and to validate the mechanism with high-resolution simulations.

Findings

Micro-jets reach velocities over 1000 m/s.

Resonant bubble pairs develop in a narrow parameter regime.

Potential flow models accurately predict bubble interface evolution.

Abstract

We reveal for the first time by experiments that within a narrow parameter regime, two cavitation bubbles with identical energy generated in anti-phase develop a supersonic jet. High-resolution numerical simulation shows a mechanism for jet amplification based on toroidal shock wave and bubble necking interaction. The micro-jet reaches velocities in excess of 1000 m/s. We demonstrate that potential flow approximation established for Worthington jets accurately predicts the evolution of the bubble gas-liquid interfaces.