LOCALIZATION OF THE DYNAMIC TWO-PARAMETER SUBGRID-SCALE MODEL AND APPLICATION TO NEAR-WALL TURBULENT FLOWS

摘要

The dynamic two-parameter mixed model (DTPMM) has been recently introduced in the large eddy simulation (LES). However, current approaches in the literatures are mathematically inconsistent. In this paper, the DTPMM has been optimized using the functional variational method. The mathematical inconsistency has been removed and a governing system of two integral equations for the model coefficients of the DTPMM has been obtained. An effective solver has been proposed to solve this complex integral system. Turbulent Couette flow is used in numerical simulations to validate this new optimal DTPMM and some significant features have been obtained. Coherent structures relating to the vortex motion of large vortices have been investigated, using the vortex λ_2-definition of Jeong and Hussain (1995). The numerical results agree with the classical wall law of von Karman (1939) and experimental correlation of Aydin and Leutheusser (1991).