Computation and Modeling of Heat Transfer in Wall-Bounded Turbulent Flows.

摘要

The dissimilarity between streamwise velocity and temperature in non- perturbed and perturbed turbulent channel and plane Couette flows was addressed using direct numerical simulations. The objective was to obtain insights that can aid turbulent heat-transfer modeling for non-equilibrium turbulent flows, based on the Reynolds stress. For perturbed flow different kind of perturbation like as blowing, suction, pressure gradient steps, etc, were used. It was found that, to some extent, the dissimilarity for both perturbed turbulent flow configurations (channel and Couette) are analogous, and that turbulence contribution to the mean-field dissimilarity was only a minor part in comparison with the contribution of pressure gradient. The contribution to dissimilarity by turbulence depends almost entirely on mean field dissimilarity. A simple transformation of the Reynolds stress can be used as a model for turbulent heat fluxes, which gives a reasonable a priori prediction of the heat fluxes in perturbed turbulent flows.