Cavitation simulation using a new simple homogeneous cavitation model

In this paper, preliminary simulations of cavitating flows in two cases, for a two-dimensional convergent-divergent nozzle and a two-dimensional Clark Y-11.7% hydrofoil, are carried out based on our new simple homogeneous cavitation model. The model treats liquid-vapor two-phase flows as usual homogeneous cavitation model but it considers two extreme conditions; the bubbly flow with dispersed bubbles in continuous liquid phase and mist flow with dispersed liquid droplets in continuous vapor phase, which are switched depending upon the local volumetric fraction of two phases, i.e. the void fraction. To enhance the unsteadiness due to the instability at the cavity interface, the turbulent shear stress is modified based on the fluid properties of continuum phase. The results are compared to the previous experimental measurements and the results simulated with Schnerr-Sauer cavitation model. It is found that turbulent shear stress has important effects on cavitation unsteadiness. However, time-averaged lift and drag characteristics of hydrofoil against cavitation are not well reproduced regardelss of cavitation model and turbulence modification.