Numerical solution of turbulent flow past a backward facing step using a nonlinear Kepsilon model
Abstract
The problem of turbulent flow past a backward facing step is important in many technological applications and has been used as a standard test case to evaluate the performance of turbulence models in the prediction of separated flows. It is well known that the commonly used kappaepsilon (and Kl) models of turbulence yield inaccurate predictions for the reattachment points in this problem. By an analysis of the mean vorticity transport equation, it will be argued that the intrinsically inaccurate prediction of normal Reynolds stress differences by the Kappaepsilon and Kl models is a major contributor to this problem. Computations using a new nonlinear kappaepsilon model (which alleviates this deficiency) are made with the TEACH program. Comparisons are made between the improved results predicted by this nonlinear kappaepsilon model and those obtained from the linear kappaepsilon model as well as from secondorder closure models.
 Publication:

National Aeronautics and Space Administration Report
 Pub Date:
 December 1987
 Bibcode:
 1987nasa.reptX....S
 Keywords:

 Backward Facing Steps;
 KEpsilon Turbulence Model;
 Models;
 Nonlinear Systems;
 Numerical Analysis;
 Turbulence;
 Turbulent Flow;
 Computer Programs;
 Nonlinearity;
 Reattached Flow;
 Reynolds Stress;
 Separated Flow;
 Transport Properties;
 Vorticity;
 Fluid Mechanics and Heat Transfer