
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.