Dynamic subgrid-scale modeling for large-eddy simulations in complex topologies

The dynamic eddy-viscosity relationship is a suitable choice for modeling t he subgrid-scales (SGS) in a large-eddy simulation (LES) of complex turbule nt flows in irregular domains. This algebraic relationship is easy to imple ment and its dynamic coefficient will give negligible turbulent viscosity c ontributions in the flow regions that are irrotational or laminar. Its fine -scale turbulence predictions can be qualitatively reasonable if the local grid resolution maintains the SGS field predominantly within the equilibriu m range of turbulent energy spectra. This performance is given herein by tw o curvilinear coordinate forms of the dynamic Smagorinsky, model that are f ormally derived and a-priori tested using the resolved physics of the cylin der wake. The consei-vative form evaluates the coefficient in the computati onal (transformed) space whereas its non-dynamic conservative counterpart o perates in the, physical domain. Although both forms equally captured the r eal normal SGS stress reasonably well, the real shear stress and dissipatio n rates were severely, under-predicted. Mixing the eddy-viscosity choice wi th a scale-similarity model can ease this latter deficiency.