Numerical investigations of the bubble collapse near an elastic plate

Abstract

In the present study, a numerical method is presented to investigate the dynamics of a sphere bubble collapsing near an elastic plate. Taking the fluid compressibility into account, the pressure and the fluid velocity are calculated by the reformulated continuity equation and momentum equation of multiphase flow. The interface between water and air is tracked by the volume-of-fluid (VOF) method, and the immersed boundary method (IB) is also introduced to simulate the interaction between elastic plate and bubble collapse. The validation of this numerical method of effectiveness and accuracy has been conducted by the comparison between simulation results and the experiment where a spark-generated bubble collapsed above an elastic plate in a water tank. To capture the process of the bubble collapse, a high-speed camera is introduced to record the temporal evolution of the bubble in the experiment. During the collapse stage, the simulated evolutions of the bubble shape from the present numerical method agree well with the experimental observations. Furthermore, the effect of the elastic modulus of the plate on bubble dynamics is numerically investigated. In the present study, three elastic moduli are adopted which are 33.1GPa, 66.2GPa and 331GPa respectively. Numerical results on the temporal evolution of bubble patterns, flow structures and the deformation of the elastic plate are analyzed in details. These results show that the plate with a higher elastic modulus has a faster response to the bubble collapse. The novelty of the present numerical method is combining the fluid compressibility, VOF and IB methods together to numerically investigate the interaction between the bubble and the elastic plate with the high elastic modulus during the collapse stage.