Direct numerical simulation of one-sided forced thermal convection in square ducts

We carry out direct numerical simulation (DNS) of forced thermal convection in one-sided heated square ducts and compare the global heat transfer to the idealized case of uniformly heated walls, and also to the case of plane channel flow with one-sided heating. DNS results reveal a reduction of global heat transfer of about 10% at unit Prandtl number and friction Reynolds number Reτ ≈ 2000, which is consistent with the values reported in early experiments. The global heat transfer of square ducts matches very well the one of plane channel flow with the same boundary conditions, at matched bulk Reynolds number based on the effective diameter.