Inter-Bubble Interactions in Ultrasonically Excited Microbubble Clusters

Microbubbles (MBs) have been utilized in a variety of applications ranging from medicine to chemistry. There have been extensive studies on many aspects of microbubble dynamics. The majority of previous theoretical studies examine the oscillations of single microbubbles. In most applications multiple microbubbles form clusters. Oscillating microbubbles generate secondary pressure waves in the medium which have been shown to modify the dynamics of neighboring MBs. Large microbubble clusters have not been studied due to the complexity of solving many coupled differential equations governing the dynamics of a large number of microbubbles. This work expands on previous works conducted on the study of multiple bubble interactions. Two approaches are introduced to simulate large clusters. Inter-bubble interactions are classified and used to explain and predict collective behavior within large polydisperse clusters. This work shows that even identical MBs within a monodisperse cluster do not necessarily exhibit identical behavior.