抄録
Direct numerical simulations have been performed for turbulent heat and momentum transfer in porous channel flow, on which similar thermal and mechanical conditions are imposed. On the porous surface the transpiration is assumed to be proportional to the local pressure fluctuations (Jimenez et al. 2001 J. Fluid Mech. 442 89-117). Turbulent heat and momentum transfer is found to be significantly enhanced by the appearance of large-scale spanwise rolls from a linear instability of shear layer over the permeable wall. The physical mechanism of this dissimilarity is interpreted in terms of the relevance of the spanwise rolls with ther induced turbulent heat flux and Reynolds stress. The correlation between the wall-normal velocity and fluctuation streamwise pressure gradient, induced by the spanwise rolls, is shown to play a role in the dissimilar heat transfer enhancement.
