Application of Different Subgrid-Scale Models used in Large-Eddy Simulation of Subsonic Channel Flow

Turbulent boundary layer flow is a basic phenomenon that exists widely inside and outside the aircraft. This phenomenon is of primordial interest for fundamental research as well as for numerical modeling. Large-eddy simulation(LES) has been widely applied to simulate turbulent flow due to its ability to capture main flow details and moderate computational cost. Based on cell-centered finite difference method, the 4^th-order compact center scheme was used to discretize convective Fluxes. Five different subgrid-scale(SGS) models were applied to simulate the isothermal-wall channel flow at Re = 3 000, Ma = 0.5, namely the implicit model, the Smagorinsky model(SM), the dynamic Smagorinsky model(DSM), the wall-adapting local eddy-viscosity model(WALE) and coherent structures model(CSM). Compared to experimental and direct numerical simulation(DNS) results, it's found that there is no evident discrepancy in mean temperature, mean density and mean streamwise velocity between different SGS models. These quantities, therefore, are not proper to distinguish SGS models. The greater dissipative the SGS model is, the smaller the wall friction velocity and friction coefficient are. As for fluctuating quantities associated with velocity, the error of results obtained by different models is larger near the wall and the peak, while smaller near the center line. Results from all explicit models are higher than reference value at the peak of fluctuating velocity in streamwise direction, while lower in spanwise and wall-normal directions. Considering eddy viscosity coefficient, DSM and CSM satisfy the relation that the eddy viscosity is proportional to the cube of dimensionless distance from the wall, and the slope of SM is smaller while the slope of WALE is larger.