Numerical study on the influence of interphase interaction in sheet/cloud cavitating flows around a 2D hydrofoil

We investigated the influence of interphase interaction on unsteady sheet/cloud cavitating flows around a 2D hydrofoil numerically. In the computations, the homogeneous (without the consideration of interphase interaction) and inhomogeneous (with the consideration of interphase interaction) multiphase flow models are used, respectively. The inhomogeneous model assumes that both phases co-exist at every point in the flow field and each phase is governed by its own set of conservation laws. The exchanges of mass, interphase drag force and momentum transfer induced by interphase mass transfer are treated explicitly as transfer terms. The results show that the distributions of interphase drag force and momentum transfer induced by mass transfer are highly related with the velocity difference of two phases and interphase mass transfer rate, respectively. Without the consideration of interphase interaction, the over-prediction of turbulent eddy viscosity in the rear of attached cavity causes the reentrant jet to lose its momentum and becomes too weak to cut across the cavity sheet. However, when considering the interphase interaction, the predicted turbulent kinetic energy in the rear of attached cavity can be reduced considerably; thus, turbulent eddy viscosity drops significantly in this region, and the reentrant jet becomes much stronger, so typical cloud cavitation shedding occurs. Compared with those predicted without the consideration of interphase interaction, a better agreement with experimental results concerning the time evolution of cavity shape, time-averaged lift/drag coefficient, frequency and mean u-velocity profiles is obtained with the consideration of interphase interaction.