Turbulent Separated Flow Past a Backward-Facing Step: A Critical Evaluation of Two-Equation Turbulence Models
Abstract
The ability of two equation models to accurately predict separated flows is analyzed from a combined theoretical and computational standpoint. Turbulent flow past a backward facing step is chosen as a test case in an effort to resolve the variety of conflicting results that have been published during the past decade concerning the performance of two-equation models. It is found that the errors in the reported predictions of the K-epsilon model have two major origins: (1) numerical problems arising from inadequate resolution, and (2) inaccurate predictions for normal Reynolds stress differences arising from the use of an isotropic eddy viscosity. In adequacies in near wall modeling play a substantially smaller role. Detailed calculations are presented which strongly indicate the standard K-epsilon model -- when modified with an independently calibrated anisotropic eddy viscosity -- can yield surprisingly good predictions for the backstep problem.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1991
- Accession Number
- ADA233478
Entities
People
- C. G. Speziale
- S. Thangam