Numerical Study on Collapse of a Cavitating Cloud of Bubbles

One of the major causes of wear on ship hydrofoils is cavitation. Clouds of interacting bubbles behave nonlinearly and can experience very sudden changes in void fraction. These nonlinear collapsing mechanisms can result in a coherent collapse of bubble clouds which have great damage potential. In this study the model, proposed by Wang and Brennen [1999], has been implemented. This model employs the fully nonlinear continuum mixture equations coupled with the Rayleigh-Plesset equation. The set of equations is solved using a Lagrangian integral method. The sensitivity of the results for parameters such as the initial void fraction of the cloud, initial cloud size as well as characteristics of the imposed pressure perturbation, has been investigated. Based on results of a RANS method for the flow around a hydrofoil with shedding sheet cavities, an equivalent cavitated cloud and corresponding pressure perturbation has been determined that serves as input for the bubble cloud method.