Large-eddy simulation of compressible flows using a spectral multidomain method

This paper discusses the development of a high-order, multidomain-based large-eddy simulation (LES) methodology for compressible flows. The LES model equations are approximated on unstructured grids of non-overlapping hexahedral sub-domains providing geometric flexibility. In each domain a high-order Chebyshev polynomial approximation represents the solution ensuring a highly accurate approximation with little numerical dispersion and diffusion. The sub-grid scale stress in the filtered LES equations is modeled with a dynamic eddy-viscosity model, while the heat flux is represented with an eddy diffusivity model. employing a turbulent Prandtl number. The model constants are evaluated through a flexible dynamic procedure that uses a high-order domain level filtering for the discrete test filter. The LES methodology is tested in a decaying isotropic turbulence and a channel flow. The LES method improves the resolution of the turbulence spectrum as compared with a direct numerical simulation (DNS) with the same method at the same grid resolution. The averaged and second-order statistics for LES computations are in close agreement with published results and resolved DNS. The high-order LES methodology requires fewer degrees of freedom as compared with lower-order LES methodologies to accurately resolve the turbulent flows. Copyright (C) 2008 John Wiley & Sons, Ltd.