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

Abstract

A numerical study ofthe heat transfer characteristics and turbulent structure is carried out in a three-dimensionalturbulent boundary layer with longitudinal vortices. Longitudinal vortices are capable of stronglyperturbing the turbulent and thermal boundary layer, which cause the anisotropy of turbulentintensities and augmentation of the heat transfer. This study uses a second-moment closure suchas the Reynolds Stress Model (RSM) to capture the anisotropy of the turbulent structureeffectively and the eddy-diffusivity model for predicting the thermal boundary layer. It can beconcluded for turbulent flow that the RSM can produce the more accurate predictions forcapturing the anisotropy than the standard k– ε model. Also, the results of heat transfer show thatdisturbing of the boundary layer causes the highest level of Stanton number in the region whichthe flows are directed toward the wall, but the vortices core is a region of relatively lowermixing. The eddy-diffusivity model for prediction of the thermal boundary layer can producereasonably good agreement with the experimental data qualitatively. However, for more accurateprediction, it may be thought that the more elaborate model, such as the second-moment closure,for the turbulent-scalar-transport terms are required.