Modeling of the Reynolds-stresses equation. 3. Description of the Reynolds-stresses dissipation rate

E. P. Sukhovich

Institute of Physics, University of Latvia, Salaspils-1, LV_2169, Latvia

Abstract
The modeling of all terms of the exact transport equation for the dissipation rate tensor is considered. The models for unknown correlations are based on tensor symmetry properties and assumption that anisotropy in the dissipation rate is relatively small. The starting point of this paper was the familiar approximations for the terms of the dissipation rate equation. These approximations contain a system of empirical coefficients, which must be determined. Basically three methods may be employed to determine empirical coefficients and form of the modelled terms: indirect method, direct comparison of the closure models to experimental data for terms of exact equation and direct comparison to numerical simulation data. The terms in the exact equation for dissipation rate tensor cannot be measured and therefore information on these terms can be obtained from direct numerical simulation (DNS) data only. The system of empirical coefficients has been determined based on the DNS data for a developed channel flow. Judging from the comparison with DNS data, the new model is better than the existing models investigated.Figs 7, Refs 14.