Two- and three- dimensional heat transfer over a wavy wall

In the present study, turbulent flow and heat transfer in a square duct with a heated wavy wall are investigated numerically using the Large Eddy Simulation (LES). A thorough validation of the numerical approach is done versus the existing results for both flat-wall square ducts and wavy-wall channels. It is demonstrated that a very good agreement is achieved with the literature in terms of global and local flow and heat transfer parameters. A comparison of two- and three- dimensional flow and heat transfer over the wavy wall is also performed in order to investigate the differences between the flow in a channel and the flow in a duct, where the flow and consequently the heat transfer are very much affected by the presence of the duct corners. In fact, it is shown that the existence of the secondary flows encountered in the regions near the duct corners cause a temperature distribution along the spanwise direction.