In the case of Detached Eddy Simulations (DES), there are two regions in a computational domain that are treated in RANS-like and LES-like manners. The original Spalart-Allmaras DES model (DES97) formulation is based on the assumption that the wall-parallel grid spacing near the wall is in excess of the boundary-layer thickness \(\delta\) by a good margin so that the entire boundary layer can be handled by RANS [1].
Settings of DESModelRegions
In OpenFOAM, we can visually check these regions using the DESModelRegions function objects. It is also available in iconCFD.