A critical evaluation of twoequation models for near wall turbulence
Abstract
A basic theoretical and computational study of twoequation models for nearwall turbulent flows was conducted. Two major problems established for the Kepsilon model are discussed, the lack of natural boundary conditions for the dissipation rate and the appearance of higherorder correlations in the balance of terms for the dissipation rate at the wall. The Komega equation is shown to have two problems also: an exact viscous term is missing, and the destruction of the dissipation term is not properly damped near the wall. A new Ktau model (where tau = 1/omega is the turbulent time scale) was developed by inclusion of the exact viscous term, and by introduction of new wall damping functions with improved asymptotic behavior. A preliminary test of the new model yields improved predictions for the flatplate turbulent boundary layer.
 Publication:

AIAA, Fluid Dynamics, 21st Plasma Dynamics and Lasers Conference, 21st, Seattle, WA, June 1820, 1990. 17 p.
 Pub Date:
 June 1990
 Bibcode:
 1990fdpd.confV....S
 Keywords:

 Computational Fluid Dynamics;
 KEpsilon Turbulence Model;
 Turbulence Models;
 Turbulent Boundary Layer;
 Wall Flow;
 Asymptotic Methods;
 Boundary Conditions;
 Boundary Value Problems;
 Energy Dissipation;
 Kinetic Energy;
 Turbulent Flow;
 Fluid Mechanics and Heat Transfer