When sound slows down bubbles

TL;DR

This study demonstrates that applying specific acoustic noise to a fluid can significantly slow down bubbles by inducing Faraday waves, which increase drag without affecting radial oscillations.

Contribution

It provides experimental evidence that acoustic noise matching a bubble's resonance can slow bubbles via Faraday wave generation, a novel insight into bubble dynamics control.

Findings

Acoustic noise matching the bubble's resonance slows it down.

Faraday waves are triggered at a critical sound pressure threshold.

Radial oscillations do not influence the mean bubble velocity.

Abstract

We present experimental evidence that a bubble moving in a fluid in which a well-chosen acoustic noise is superimposed can be significantly slowed down for moderate acoustic pressures. Through mean velocity measurements, we show that a condition for this effect to occur is for the acoustic noise spectrum to match or overlap the bubble's fundamental resonant mode. By rendering the bubble's oscillations and translational movements using high speed video, we evidence that radial oscillations have no effect on the mean velocity, while above a critical sound pressure threshold, Faraday waves are triggered and are responsible for the bubble's drag increase.