A systematic study on hybrid RANS/LES models for a high-order discontinuous Galerkin scheme

Abstract

In this work we investigate the performance of several hybrid RANS/LES models in a high-order discretization framework. Many hybrid models are indeed tailored around finite volume methods, therefore it is of particular interest to examine their performance within the context of high-order schemes. The numerical study is carried out using an incompressible modal Discontinuous Galerkin solver. The assessment includes the two major classes of non-zonal DES-like turbulence models, i.e. DDES and IDDES. Cutting-edge subgrid length scales are tested in an attempt to mitigate the most common problems affecting DES-like hybrid turbulence models, namely the gray area and modeled-stress depletion. The effect of a low-Reynolds correction that acts against the eddy viscosity drop outside of the RANS region is also taken into consideration. The analysis involves the simulation of some baseline flow problems, like the channel flow at $R{e}_{\tau }=\{400,5200\}$, the backward-facing step and the flow past a NACA0012 foil at high angle of attack.