Physical investigation of acoustic waves induced by the oscillation and collapse of the single bubble

Guohao Huang; Mindi Zhang; Lei Han; Xiaojian Ma; Biao Huang

doi:10.1016/j.ultsonch.2020.105440

Physical investigation of acoustic waves induced by the oscillation and collapse of the single bubble

Ultrason Sonochem. 2021 Apr:72:105440. doi: 10.1016/j.ultsonch.2020.105440. Epub 2020 Dec 24.

Authors

Guohao Huang¹, Mindi Zhang², Lei Han¹, Xiaojian Ma¹, Biao Huang³

Affiliations

¹ School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China.
² School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China. Electronic address: zmd1971@bit.edu.cn.
³ School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China. Electronic address: huangbiao@bit.edu.cn.

Abstract

The objective of this paper is to apply both experimental and numerical methods to investigate acoustic waves induced by the oscillation and collapse of a single bubble. In the experiments, the schlieren technique is used to capture the temporal evolution of the bubble shapes, and the corresponding acoustic waves. The results are presented for the single bubble generated by a low-voltage bubble generator in the free field of water. During the numerical simulations, a three-dimensional (3D) weakly compressible model is introduced to investigate the single bubble dynamics, including the generation and propagation of acoustic waves. The results show that (1) Compression wave, rarefaction wave and shock wave are generated during expansion stage, collapse stage and rebound stage of the bubble respectively. (2) Compression waves are induced by the rapid expansion of the bubble and eventually steepen into one shock wave propagating outward in the liquid, then another strong shock wave is emitted at the final collapse stage. The velocity and pressure of the liquid field increases after the shock wave. (3) Rarefaction waves are generated during the collapse stage due to the contraction of the bubble. The rarefaction wave reduces the liquid pressure and its spatial distribution is dispersive. The pressure of these acoustic waves and their effect on the liquid velocity attenuate with the increase of propagation distance.

Keywords: Acoustic wave; Bubble dynamics; Experimental and numerical methods; Shock wave.