Bubble-bubble interaction: A potential source of cavitation noise

TL;DR

This paper investigates how interactions between microbubbles can generate cavitation noise, especially negative pulses, through a nonlinear multibubble model, explaining acoustic signals observed in biological and physical phenomena.

Contribution

It introduces a nonlinear multibubble model that explains negative pulses in cavitation noise as resulting from microbubble interactions, advancing understanding of cavitation noise mechanisms.

Findings

Negative pulses are caused by reflected pressure waves from microbubbles.

High internal pressure in microbubbles prevents negative pulse generation.

Microbubble interactions are key to cavitation noise in biological systems.

Abstract

The interaction between microbubbles through pressure pulses has been studied to show that it can be a source of cavitation noise. A recent report demonstrated that the acoustic noise generated by a shrimp originates from the collapse of a cavitation bubble produced when the shrimp closes its snapper claw. The recorded acoustic signal contains a broadband noise that consists of positive and negative pulses, but a theoretical model for single bubbles fails to reproduce the negative ones. Using a nonlinear multibubble model we have shown here that the negative pulses can be explained by considering the interaction of microbubbles formed after the cavitation bubble has collapsed and fragmented: Positive pulses produced at the collapse of the microbubbles hit and impulsively compress neighboring microbubbles to generate reflected pulses whose amplitudes are negative. Discussing the details of the noise generation process, we have found that no negative pulses are generated if the internal pressure of the reflecting bubble is very high when hit by a positive pulse.