A modified approach to the bubble-bubble interaction-based cavitation model for improved mass transfer prediction in unsteady cavitating flows

In cavitating flows, the collective dynamics of bubble clusters differ fundamentally from those of isolated bubbles due to intense bubble-bubble interactions (BBI). Conventional cavitation models, usually based on the single-bubble hypothesis, overlook these interaction mechanisms. This omission results in overestimation of phase transition rates and inaccuracies in predicting unsteady shedding dynamics. A new mass-transfer model is developed within the transport-equation framework by accounting for BBI effects. This is achieved by utilizing a modified Rayleigh-Plesset equation that explicitly incorporates the pressure shielding effect from neighboring bubbles. The interaction range parameters for growth ((Formula presented) ) and collapse ((Formula presented) ) are theoretically derived and calibrated against discrete bubble cluster simulations, a process that eliminates the need for case-specific empirical tuning. The proposed model is implemented in OpenFOAM and validated against experimental data from two-dimensional (2D) flow over a Clark-Y hydrofoil and three-dimensional (3D) flow past a wedge-shaped bluff body. Compared with the Schnerr-Sauer model, the proposed model does not require adjustable parameters and significantly improves the prediction accuracy of hydrodynamic loads while accurately capturing complex unsteady features, such as re-entrant jet dynamics and Strouhal numbers associated with cloud shedding. This work offers a physical approach to bridging microscopic bubble interactions and macroscopic cavitating flow simulations. Future refinements of this interaction-based model could incorporate dynamic variations in bubble population and non-spherical deformations to further broaden its predictive scope.