DIRECT NUMERICAL-SIMULATION OF A TURBULENT CHANNEL FLOW WITH A LINEARSPANWISE MEAN TEMPERATURE-GRADIENT

Spanwise heat transfer in wall turbulence was studied in a turbulent c hannel flow having a linear spanwise variation of time-mean temperatur e just the same as the spanwise variation of wall-temperature. The res ults of direct numerical simulation (DNS) for various Prandtl numbers ranging from 0.1-1.5 were compared with existing DNS data for ordinary two-dimensional heat transfer from uniformly heated walls. The Prandt l number effect on the spanwise eddy diffusivity of heat was found to be quite similar to that on the wall-normal component. Similarity was also observed between the destruction of the spanwise turbulent heat f lux and that of the wall-normal component. (C) 1998 Elsevier Science L td. All lights reserved.