Comparison of VLES and LES Turbulence Modeling for Swirling Turbulent Flow

Swirling flow has been widely used in gas turbine and aero-engine combustor to stabilize the flame. However, accurate numerical prediction of the swirling turbulent flow is difficult due to complex vortex movement in the flow, and turbulence modeling is a key factor. To assess the turbulence modeling in predicting the swirling flow, numerical studies are conducted for a well-documented swirling flow case. Three turbulence models are applied in the framework of scale resolved models, i.e. a newly developed VLES (Very-large eddy simulation) model, two LES (Large eddy simulation) models including the WALE (Walladapting local eddy viscosity model) and CSM (Coherent Structure Method). Numerical results are compared with the experimental results including the mean and RMS velocities. It is found that VLES model performs best among the three models and the other two LES models give comparable predictions. The complex vortex structures are explored based on the unsteady simulation results. The study demonstrates the high potential of VLES modeling for accurate prediction of complex swirling flow.