Turbulence Models for Flows with Free Surfaces and Interfaces

The Reynolds-averaged equations of motion for turbulent interfacial flows are developed. A new model for the correlation of the mean pressure with the fluctuations of the interface location is introduced. A parameter referred to as turbulent surface tension coefficient is introduced that models the effect of turbulence on increasing the surface tension force. In addition, a model for the correlation of the mean fluctuations of the volume fraction with velocity is presented. A volume-of-fluid-based model is used to simulate the dynamics of the interface between the two immiscible fluids. The new turbulence models are used to simulate a two-dimensional Kelvin-Helmholtz instability at high-Reynolds-number flows. In addition, the turbulence models are used to simulate spreading of a plane turbulent water jet in air.