Numerical Investigation of the Turbulent Heat Transfer Mechanism Near the Wall by the Unsteady Streamwise Pseudo-Vortical Motion Model

Abstract

The unsteady streamwise pseudo-vortical motion model developed by Kasagi et al. (1985) is used in a numerical analysis of the turbulent heat transfer near the wall for various Prandtl-number fluids under the wall boundary conditions of constant heat flux and constant temperature. Unlike the typical methodology based on Reynolds decomposition, the algebraic expressions of three fiuctuating velocities given by the model are directly introduced into the governing energy equation. From the numerical solution of the unsteady thermal field, the near-wall behavior of statistical quantities is obtained. Both the predicted turbulent heat flux and turbulent Prandtl number are appreciably dependent upon the Prandtl number under the strong influence of the prescribed wall boundary condition. In addition, the production and diffusion of temperature fluctuation associated with coherent turbulence structure are calculated and are qualitatively in good agreement with the experiment.