A dynamic subgrid-scale eddy viscosity model with a global model coefficient

In the present study, a dynamic subgrid-scale eddy viscosity model is proposed for large eddy simulation of turbulent flows in complex geometry. A subgrid-scale eddy viscosity model recently proposed by Vreman [Phys. Fluids 16, 3670 (2004)] which guarantees theoretically zero subgrid-scale dissipation for various laminar shear flows, is considered as a base model. A priori tests with the original Vreman model show that it predicts the correct profile of subgrid-scale dissipation in turbulent channel flow but the optimal model coefficient is far from universal. A dynamic procedure of determining the model coefficient is proposed based on the "global equilibrium" between the subgrid-scale dissipation and the viscous dissipation. An important feature of the proposed procedure is that the model coefficient determined is globally constant in space but varies only in time. A posteriori tests of the proposed dynamic model are conducted through large eddy simulations of forced isotropic turbulence at Re-lambda=103, turbulent channel flows at Re-tau=180 and 590, flow over a circular cylinder at Re-d=3900, and flows over a sphere at Re-d=3700 and 10(4). The proposed dynamic model produces excellent performance for all flows considered. As shown in the present paper, the proposed model is robust and it can be readily applied to complex flows without homogeneous direction. (c) 2006 American Institute of Physics.