Large-eddy simulation of particle-driven gravity currents using the Relaxation-Term model

Abstract

We present Large-Eddy Simulations (LES) of two laboratory-scale lock-exchange flows at Grashof numbers of up to 108 and a Schmidt number of unity. The unresolved subgrid scales (SGS) are modeled with the Relaxation-Term (RT) approach. We compare the LES results with those of fully resolved Direct Numerical Simulations (DNS) to rate the quality of the approach. We find that reductions of the grid resolution by factors of about four in each spatial and in the temporal direction are feasible compared to marginally resolved DNS. This corresponds to a reduction of computer time by about two orders of magnitude.