A New SGS Model Based on Selective Structure Function and WALE Models

Experiences show that the various LES models yield good results when they are applied to homogeneous turbulent flows and that the cutoff is placed sufficiently far into the inertial range of the spectrum. In other cases, as in transitional flows, highly anisotropic flows, highly under-resolved flows, or those in high energetic disequilibrium, the subgrid models behave much less satisfactorily. In order to improve the prediction ability of subgrid scale models in these regimes some method is used such as Selective Structure Function (SSF) model. Two significant incompetence of selective model is definition the angle for switching off the eddy viscosity in the regions where the flow is not threedimensional enough and switching off function. The main goal of this research is to understand that can be improved the ability of SSF with change the eddy viscosity function for angles less than switching off angle.