NUMERICAL INVESTIGATION OF TURBULENT SEPARATING FLOW IN AN ASYMMETRIC DIFFUSER

摘要

A computational study has been performed to compare the flow quantities with the experimental test case of Obi et al. (1993), which involves separation from a plane wall and subsequent reattachment in the downstream duct of an asymmetric diffuser. The Reynolds number, based on an upstream reference velocity and inlet channel height, is 21200. The incompressible Navier-Stokes equations for turbulent flow has been solved by using a standard finite volume CFD code. Standard k-ε model and Hybrid turbulence model (Basara and Jakirlic, 2001) have been tested. The Hybrid turbulence model demonstrates an improved result while standard k-ε model fails to capture the downstream flow behavior. There are, however some shortcomings in these models particularly in the development of flow after reattachment, which is always predicted to be too slow.