Heat transfer in a three-dimensional turbulent boundary layer with longitudinal vortices

Abstract

A numerical study of the heat transfer characteristics and turbulent structure is carried out in a three-dimensional turbulent boundary layer with longitudinal vortices. Longitudinal vortices are capable of strongly perturbing the turbulent and thermal boundary layer, which cause the anisotropy of turbulent intensities and augmentation of the heat transfer. This study uses a second-moment closure such as the Reynolds Stress Model (RSM) to capture the anisotropy of the turbulent structure effectively and the eddy-diffusivity model for predicting the thermal boundary layer. It can be concluded for turbulent flow that the RSM can produce the more accurate predictions for capturing the anisotropy than the standard k-epsilon model. Also, the results of heat transfer show that disturbing of the boundary layer causes the highest level of Stanton number in the region which the flows are directed toward the wall, but the vortices core is a region of relatively low er mixing. The eddy-diffusivity model for prediction of the thermal boundary layer can produce-reasonably good agreement with the experimental data qualitatively. However, for more accurate prediction, it may be thought that the more elaborate model, such as the second-moment closure, for the turbulent-scalar-transport terms are required. (C) 1998 Elsevier Science Ltd. All rights reserved.