A numerical study of the early-stage dynamics of a bubble cluster

The dynamics of multiple cavitating bubbles is numerically simulated, with the ambient pressure lower than the saturated vapor pressure, using a pseudopotential lattice Boltzmann method (LBM) coupled with the Carnahan-Starling equation of state. Dual-bubble and multi-bubble systems are tested, and the method for the bubble cluster is validated. It is found that the bubble can either grow or collapse in the early stage, depending on the configuration of the bubble cluster, characterized by the bubble number, the inter-bubble distance and the initial radii. In the induced flow, the bubbles are mutually interacted. Scaling relations of the interaction are proposed according to the numerical results. With consideration of the interactions, the simplified Rayleigh-Plesset equations (RPEs) for multiple bubbles can describe the evolution of the bubbles approximately. The results may serve as the basis for improved cavitation models.