Abstract
We carried out direct numerical simulation for turbulent flow and heat transfer in a channel with gentle two-dimensional wavy surfaces, and investigated the possibility of drag reduction and heat transfer enhancement. The slip velocity was assumed to be proportional to the velocity at an adjacent grid point to the wall. Three proportional constants are used. The computational results show that the mean wall-shear stresses for the wavy walls do not depend on the slip velocity, and are lower than those for a non-slip flat wall. The mean Nusselt number for the wavy walls increases with an increase in the slip velocity. This increase in the Nusselt number is due to the decrease in the mean temperature gradient in the buffer region, which is due to the gradient of turbulent heat flux.
