Large-eddy simulations (LES) and Reynolds-averaged Navier–Stokes (RANS) calculations of the flow in two asymmetric three-dimensional diffusers were performed. The setup was chosen to match an existing experiment with separation. Both diffusers possess the same expansion ratio but differ in performance. The aim of the present study is to find the least expensive method to reliably and with reasonable accuracy account for the impact of the change in geometry. RANS calculations failed to predict both the extent and location of the separation. In contrast, LES with wall-functions delivered results within the accuracy of the experimental data.

Issue Section:
Flows in Complex Systems
Keywords:
computational fluid dynamics, flow separation, flow simulation, Navier-Stokes equations
Topics:
Diffusers, Flow (Dynamics), Simulation, Separation (Technology), Reynolds-averaged Navier–Stokes equations, Large eddy simulation
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