A dynamic global-coefficient subgrid-scale model for large-eddy simulation of turbulent scalar transport in complex geometries

Abstract

The dynamic global-coefficient subgrid-scale eddy-viscosity model by You and Moin [Phys. Fluids 19, 065110 (2007)] is generalized for large-eddy simulation of turbulent flow with scalar transport. The model coefficient for subgrid-scale scalar flux which is constant in space but varies in time is dynamically determined based on the "global conservation" of the transport equation for scalar variance. Large-eddy simulations of turbulent flow with passive scalar transport through a channel and over a backward-facing step show that the present model has a similar predictive capability as the dynamic Smagorinsky model. The present dynamic model is especially suitable for large-eddy simulation of turbulent flow with scalar transport in complex geometries since it does not require any spatial and temporal averaging or clipping of the model coefficient for numerical stabilization and requires only a single-level test filter. The present model is not more complicated in implementation and not more expensive in terms of computational cost than the dynamic Smagorinsky model.