One-equation sub-grid scale model with variable eddy-viscosity coefficient

A one-equation sub-grid scale (SGS) model with a variable eddy-viscosity coefficient is developed for large-eddy simulation. The model coefficient is determined based on the shear and vorticity parameters accompanied by the hybrid time scale (Tt). The current model accounts for the SGS kinetic energy which is not considered in the dynamic Smagorinsky model (DSM). The eddy-viscosity coefficient preserves the anisotropic characteristics of turbulence in the sense that it is sensitized to non-equilibrium flows. In addition, it guarantees the positivity in the energy components. Unlike the original Smagorinsky model and DSM, the current SGS model does not need any ad-hoc damping function or clipping. The model is validated against well-documented flow cases, yielding predictions in good agreement with the direct numerical simulation (DNS) and experimental data. Comparisons indicate that the present model offers competitiveness with the DSM.