A Computational Study of the Collapse of a Cloud with 12500 Gas Bubbles in a Liquid

TL;DR

This study uses large-scale simulation to analyze the collapse dynamics of a cloud of 12,500 gas bubbles in a liquid, revealing how microjets and pressure pulses depend on local collapse conditions.

Contribution

It presents a detailed computational approach to model cloud cavitation collapse with a large number of bubbles, providing insights into microjet behavior and pressure pulse spectra.

Findings

Bubble oscillation frequency varies with collapse wave strength.

Microjet velocity depends on the bubble's radial position.

Pressure pulse rate follows an exponential distribution.

Abstract

We investigate the process of cloud cavitation collapse through large-scale simulation of a cloud composed of 12500 gas bubbles. A finite volume scheme is used on a structured Cartesian grid to solve the Euler equations, and the bubbles are discretized by a diffuse interface method. We investigate the propagation of the collapse wave front through the cloud and provide comparisons to simplified models. We analyze the flow field to identify each bubble of the cloud and its associated microjet. We find that the oscillation frequency of the bubbles and the velocity magnitude of the microjets depend on the local strength of the collapse wave and hence on the radial position of the bubbles in the cloud. At the same time, the direction of the microjets is influenced by the distribution of the bubbles in its vicinity. Finally, an analysis of the pressure pulse spectrum shows that the pressure pulse rate is well captured by an exponential law.