Acoustic emission associated with the bursting of a gas bubble at the free surface of a non-newtonian fluid

TL;DR

This study investigates the acoustic signals generated when gas bubbles burst at the surface of a non-Newtonian fluid, revealing how bubble shape and bursting dynamics influence the emitted sound.

Contribution

It provides experimental insights and a simple linear model linking bubble shape and acoustic emission in non-Newtonian fluids, advancing understanding of bubble bursting phenomena.

Findings

Acoustic signals depend on bubble shape and bursting dynamics.

The model successfully predicts frequency and duration of acoustic emissions.

Acoustic energy is highly sensitive to thin film rupture, limiting energy quantification.

Abstract

We report experimental measurements of the acoustic emission associated with the bursting of a gas bubble at the free surface of a non-newtonian fluid. On account of the viscoelastic properties of the fluid, the bubble is generally elongated. The associated frequency and duration of the acoustic signal are discussed with regard to the shape of the bubble and successfully accounted for by a simple linear model. The acoustic energy exhibits a high sensitivity to the dynamics of the thin film bursting, which demonstrates that, in practice, it is barely possible to deduce from the acoustic measurements the total amount of energy released by the event. Our experimental findings provide clues for the understanding of the signals from either volcanoes or foams, where one observes respectively, the bursting of giant bubbles at the free surface of lava and bubble bursting avalanches.