Assessment and comparison of a recent kinematic sensitive subgrid length scale in Hybrid RANS-LES

Abstract

A recent kinematic sensitive subgrid length scale, Δlsq, initially developed for LES applications, is now considered for DES. Even though it is presented as a subgrid length scale, instead of a grey area mitigation (GAM) technique, this initial study shows how it could also be a good and natural approach for addressing this well-known DES shortcoming. In this paper, the Δlsq has been compared with a well-known kinematic sensitive length scale, Δ~ω. It includes a mesh resilience and a shear layer delay study with a Decaying Homogeneous Isotropic Turbulence configuration and two Backward Facing Step configurations, respectively. Encouraging results have been obtained, indicating Δlsq as a subgrid length scale to be considered.