Approximation of subgrid-scale stresses based on the Leonard expansion

Based on the reconstruction series for subgrid-scale (SGS) stress tensor, an approximation of SGS modelling is explored, by exploiting the second term in relation to the viscous dissipation rate tensor, epsilon(ij). With an assumption of anisotropy dissipation for epsilon(ij) in analogy to RANS modelling, the second term is approximated in terms of an eddy-viscosity formulation, which, together with the first Leonard term, forms a two-term mixed model. The resulting mixed model is then examined in LES of turbulent channel flow, by which the effect of the two terms is highlighted.