Shear-Improved Smagorinsky Modeling of Turbulent Channel Flow Using Generalized Lattice Boltzmann Equation

Generalized Lattice Boltzmann Equation (GLBE) was used for computation of turbulent channel flow for which Large Eddy Simulation (LES) was employed as a turbulence model. The subgrid-Scale turbulence effects were simulated through a Shear-Improved Smagorinsky Model (SISM) which is capable of predicting turbulent near wall region accurately without any wall function. Computations were done for a relatively coarse grid with shear Reynolds number of 180 in a parallelized code. Good numerical stability was observed for this computational framework. Results of mean velocity distribution across the channel showed good correspondence with Direct Numerical Simulation (DNS) data. Negligible discrepancies were observed for computed turbulent statistics between present computations and those reported from DNS. Three-dimensional instantaneous vorticity contours showed complex vortical structures appeared in such flow geometries. It is concluded that such framework is capable of predicting accurate results for turbulent channel flow without adding significant complication and computational cost to the standard Smagorinsky model.