Experimental and numerical study of transient bubble-elastic membrane interaction

Abstract

A study of the interaction between a membrane and a submerged oscillating bubble is presented. Though the behavior of such a bubble near an elastic (relatively thick) boundary has been studied by several authors, much less attention is focused on the behavior of such a bubble near a (thin) elastic membrane. For membranes, it is the curvature and not the deflection that is responsible for a pressure buildup in the fluid close to the bubble. Due to this difference in physics, it is not a certainty if the dynamics of bubbles near a deformable elastic boundary vis-a-vis a membrane would exhibit any similarity. Our intent is a systematic study on the latter, which can be exploited in future work (e.g., in biomedical applications where elastic membranes are often involved). Experimental observations of transient bubble interaction with a thin elastic membrane are presented and the dynamics of the bubble in the vicinity of the membrane are compared to the boundary element method simulations. The bubble is generated using a very low voltage (only 55V) in contrast to the relatively much higher voltages usually employed in reported works. This is very attractive from a safety viewpoint and accords great simplification of the setup. The comparisons show that the interaction between the transient bubble and the membrane induces a perturbation on the bubble surface that strengthens the bubble contraction and can lead to mushroom shape, bubble elongation, and bubble splitting. The influence of the two main parameters, namely, the distance between the bubble and the membrane and the elasticity of the membrane, are also discussed.