LES and DES of swirling flow with rotor-stator interaction

Artikel i vetenskaplig tidskrift, 2015

A highly swirling turbulent flow engendered by the rotor-stator interaction of a swirl generator is investigated using LES and DES. The delayed DES Spalart-Allmaras (DDES-SA), improved DDES-SA, shear stress transport DDES, and a dynamic k-equation LES are studied. A mesh sensitivity study is performed on the hybrid methods, including the ability of captur-ing the details of the flow field. It is shown that all methods are capable of predicting the large-scale flow features, e.g. the vortex breakdown and the corresponding on-axis recirculation region. It is also shown that all hybrid methods capture most of the small-scale coherent structures, even with a relatively coarse mesh resolution. The various shielding functions of the hybrid methods are analyzed, distinguishing the location of the transition between RANS and LES mode.