Numerical solution of turbulent channel flow past a backward-facing step with a porous insert using linear and nonlinear k-ε models

Abstract

This work presents a numerical investigation of turbulent flow past a backward-facing-step channel with a porous insert using linear and nonlinear eddy viscosity macroscopic models. The nonlinear turbulence models are known to perform better than classical eddy-diffusivity models due to their ability to simulate important characteristics of the flow. Turbulence-driven secondary motion and the effects of streamline curvature on turbulence cannot be fully accounted for with simpler Isotropic models. Parameters such as porosity, permeability, and thickness of the porous insert are varied in order to analyze their effects on the flow pattern, particularly on the damping of the recirculating bubble after the porous insertion. The numerical technique employed for discretizing the governing equations is the control-volume method. The SIMPLE algorithm is used to correct the pressure field. The classical wall function is utilized in order to handle flow calculation near the wall. Comparisons of results simulated with both linear and nonlinear turbulence models are shown. Copyright © 2005 Begell House, Inc.