Effect of grid-filter width definition on implicitly filtered large eddy simulations using OpenFOAM

Turbulent flow over a 3D backward-facing step at a step-height Reynolds number, Reh, of 5100 is simulated in OpenFOAM using Large Eddy Simulation (LES) to investigate how the definition of the grid-filter width, Δ, influences the computed solutions. As part of this study, two different Δ definitions are tested: Δ=ΔxΔyΔz3 and Δ = max(Δx, Δy, Δz). The LES results show good agreement when compared with DNS and experimental data. The simulation results are used to further evaluate the effect of grid non-uniformity on the computation of the subgrid-scale eddy viscosity, νSGS.