Reconstructing Sub-Filter Shear Driven Instabilities for a Dual Scale Model with a Geometrically Transported Vortex Sheet

A method to predict sub-filter velocities in the presence of shear on a liquid-gas phase interface for use in a dual scale LES model is presented. The method reconstructs the sub-filter velocity field on a high resolution grid overlaid on the flow solver grid in a narrow band near the interface. A vortex sheet is applied at the interface location and transported by an unsplit geometric volume and surface area advection scheme with a Piecewise Linear Interface Construction (PLIC) representation of the material interface. At each step and desired location the shear-induced velocities can be calculated by integrating the vortex sheet and other relevant quantities over the liquid-gas surface. In an effort to keep computational cost low, the sub-grid velocity reconstruction is limited to a small number of cells near the phase interface necessary for geometric transport. The vortex sheet method is tested and compared against prior literature and a 3D implementation is discussed.