Direct numerical simulation of a turbulent channel flow with a linear spanwise nonuniformity of time-mean temperature (Examination of the turbulence statistics)

Abstract

Direct numerical simulation (DNS) was performed for a turbulent channel flow with the time-mean temperature linearly varying in the spanwise direction. Spanwise heat transfer in wall turbulence was explored in this simple case where the turbulent heat flux has only a spanwise component. The computed flow field was confirmed to be in good agreement with the DNS database constructed by Kasagi and colleagues (1992). The general trend of the presently calculated spanwise eddy diffusivity of heat is similar to the experimental data reported by Maekawa and colleagues. However, there is a considerable discrepancy between their results in the vicinity of the wall. The numerical results demonstrate that the spanwise turbulent heat flux is nearly in local equilibrium over the whole channel width excluding the viscous sublayer