Comparison of new RANS-LES hybrid methods on a tandem cylinder problem using rough meshes

Abstract

Detached eddy simulation (DES), delayed DES (DDES) and improved DDES (IDDES) hybrid RANS-LES turbulence models based on the Menter's Shear Stress Transport (SST) model as well as the DES variant of the Kok's Turbulent/Non-Turbulent model (TNT), Extra-Large Eddy Simulation (X-LES), and its newly proposed delayed and improved delayed variants (DX-LES and IDX-LES) along with the base RANS methods are compared in this paper. The comparison is made on a flow around tandem cylinders, on which mainly hybrid methods based on the one-equation Spalart-Almaras model were previously tested. The proposed models show DDES and IDDES with a different approach from the SST-based two-equation methods, which potentially improves the results and, in the case of the TNT-based DDES variant, only the blending function is dependent of the distance from the wall.