A Pressure-Based Method for Turbulent Cavitating Flow Computations

Abstract

A pressure-based algorithm is presented for turbulent cavitating flow computations. Single-fluid Navier–Stokes equations cast in their conservative form, along with a volume fraction transport equation, are employed. The flow field is computed in both phases with the vapor pressure recovered inside the cavity via a mass transfer model. A pressure–velocity–density coupling scheme is developed to handle the large density ratio associated with cavitation. While no temperature, and hence Mach number, effect is considered in the cavitation model, the resulting pressure–correction equation shares common features with that of high-speed flows, exhibiting a convective–diffusive type, instead of only a diffusive type. Furthermore, similar to high-speed cases, upwinded density interpolation in mass flux computations also aids convergence of the cavitating flow computations. The nonequilibrium effect in the context of the k-ε turbulence model, the grid distribution, and the choice of convection schemes have been computationally examined in projectile flows. While satisfactory predictions in wall pressure distribution can be made with variations in grid resolution and parameters in the cavitation model, other aspects, such as the density distribution and detailed streamline characteristics, are found to exhibit higher sensitivity to them.