Cavitation Bubble Cluster Dynamics in Collective and Bubble Resolved Models
* Presenting author
Acoustically driven bubbles in larger ensembles can lead to collective behaviour and synchronization via their mutual coupling. While in experiments synchronized bubble oscillations have been observed, also in subharmonic form, the exact mechanism of their emergence (and therefore of their description) is not fully clear. Collective models employ a type of mean field pressure within the cluster that averages in a way over the individual bubbles and thus reduces complexity of calculations. The mean field can exhibit period doubling and thus introduces the subharmonics in a "top-down" manner. On the other hand, the close-ranged coupling between bubbles favours a "bottom-up" mechanism where adjacent bubbles force each other to synchronous collapse. As a consequence, subdomains of different synchronization states may form within a cluster where individual bubbles are resolved. The present work compares collective with bubble resolved models under the aspect of synchronization and subharmonic oscillations.