
Compared to laminar flows, simulations of turbulent flows are more challenging in many ways. For the Reynoldsaveraged approach, additional equations are solved for the turbulence quantities. Since the equations for mean quantities and the turbulent quantities (
,
,
,
, or the Reynolds stresses) are strongly coupled in a highly nonlinear fashion, it takes more computational effort to obtain a converged turbulent solution than to obtain a converged laminar solution. The LES model, while embodying a simpler, algebraic model for the subgridscale viscosity, requires a transient solution on a very fine mesh.
The fidelity of the results for turbulent flows is largely determined by the turbulence model being used. Here are some guidelines that can enhance the quality of your turbulent flow simulations.