A new hybrid turbulence model applied to highly turbulent Taylor-Couette flow

Abstract

A hybrid Reynolds Averaged Navier-Stokes (RANS)/Large Eddy Simulation (LES) model based on the k equation is proposed with the quadratic stresses to stimulate the quick growth of resolved turbulence around the RANS/LES interface and remove the artificial buffer layer. The proposed hybrid model is applied to simulate the Taylor-Couette (TC) flow with different RANS/LES interface locations and Taylor numbers. The model is verified by comparing with the direct numerical simulation results and validated by experimental torques with different Taylor numbers. The model is insensitive to the interface location owing to the effect of the quadratic stress in adjusting the energy backscatter. By means of the proposed model, the shift of the mean velocity profile around the RANS/LES interface is diminished. It is revealed that the contribution of the Reynolds shear stress to transporting angular velocity in the annular gap center region rises from 20% to 50% as the radius ratio reduces from 0.909 to 0.5 in the TC flow. The tilting angle of herringbone streaks in the TC flow decreases with increasing Ta number, while varying non-monotonically with respect to the radius ratio.