A surface tension sub-grid model for phase interface dynamics

This paper reports on the development of a model for the sub-filter surface tensioninduced motion of liquid/gas phase interfaces. A key feature of the proposed model is to take the sub-filter phase interface dynamics fully into account by employing a dual-scale approach. Instead of modeling the sub-filter phase interface geometry, it is resolved on an auxillary grid using the Refined Level Set Grid approach. The required sub-filter velocity field on the auxiliary grid is reconstructed solving a PDE in a narrow band surrounding the phase interface. With the fully resolved phase interface geometry available, all previously unclosed terms in the filtered Navier-Stokes equations can be directly closed using explicit filtering.