HRT

Abstract

In the traditional hybrid RANS/LES approaches for the simulation of wall-bounded fluid turbulence, such as the detached eddy simulation (DES), the whole flow domain is divided into the inner layer and outer layer. Typically the Reynolds averaged Navier-Stokes (RANS) equation is used for the inner layer, while the large eddy simulation (LES) is used for the outer layer. The transition from the inner layer solution to the outer layer is often problematic due to lacking small scale dynamics in the RANS region. In this paper we propose to simulate the whole flow region by large eddy simulation while enforcing a RANS Reynolds stress for the inner layer. We verifed our approach by simulating three-dimensional turbulent channel flows. We were able to accurately model the mean velocity and the turbulent stress using the same grid size as DES. The application of the proposed constrained LES to other turbulent flows with separation will also be discussed.