Characterization of the interaction of two oscillating bubbles near a thin elastic membrane

Abstract

Oscillating bubbles appear in the bodily fluid during many medical treatments, for example in Extracorporeal Shockwave Lithotripsy. We report a systematic study on the complex interaction between two such bubbles and an elastic membrane, which could be a biological membrane in the human body. We have grouped our analysis into similarly sized bubbles, and differently sized bubbles. All bubbles are created at the same time. For the similarly sized bubbles, it can be broadly characterized as the splitting up of two bubbles in vertical direction perpendicular to (vertical split) and at an angle to (oblique split) the membrane surface, jetting towards each other and bubble coalescence. For the two differently sized bubbles, there is the jetting towards or away from the large bubble for the small bubble and the ‘catapult’ effect observed. The two bubbles dynamics depend on the relative bubble sizes, the distance from the membrane, and the inter-bubble distance.