A DG Implementation of a Novel Hybrid RANS/LES Technique With RANS Reconstruction

TL;DR

This paper introduces a novel hybrid RANS/LES turbulence modeling technique that reconstructs the Reynolds stress tensor without requiring an explicit RANS model, implemented within a high-order DG framework and validated on turbulent channel flow.

Contribution

The paper presents a new hybrid RANS/LES method using Reynolds stress reconstruction, eliminating the need for an explicit RANS model and demonstrating improved accuracy over pure LES.

Findings

Good agreement with DNS data for turbulent channel flow

Improved results compared to pure LES

Effective implementation within a high-order DG code

Abstract

A new hybrid RANS/LES technique, based on the hybrid filter proposed by Germano in 2004, has been studied. The novelty herein introduced is represented by the reconstruction of the Reynolds stress tensor. As a consequence, no explicit RANS model is needed. The RANS and LES terms are merged using a constant blending factor. The model is implemented in a numerical code based on a high order Discontinuous Galerkin (DG) finite element formulation. The test case considered for numerical simulations is the turbulent tur- bulent channel flow at Mach = 0.2. The comparison with available DNS data shows a good agreement and, in general, an improvement with re- spect to pure LES results, confirming that the technique herein proposed represents a promising approach to the numerical simulation of turbulent flows.