Large-eddy simulation of a bluff-body flow on unstructured grids

摘要

Large-eddy simulations of the flow around a square cylinder on coarse unstructured grids are investigated. The numerical solver is based on a mixed finite-volume/finite-element formulation. A modified Roe scheme is employed for convective terms, together with the MUSCL method to increase the order of accuracy. An upwinding parameter, γ_s, directly controls the numerical diffusion, which is formed of fourth-order space derivatives. The eddy-viscosity Smagorinsky model and its dynamic version are used for the subgrid scale (SGS) terms in the LES equations. The effects of upwinding, and, in particular, the interaction between SGS and numerical dissipation, are studied by varying the value of γ_s. The sensitivity to grid inhomogeneity and to SGS modelling also investigated. Results are compared to those obtained in other LES in the literature and to experimental data.