A numerical study is made of the unsteady flow and convection heat transfer for a heated square porous cylinder in a channel. The general Darcy-Brinkman-Forchheimer model is adopted for the porous region The parameters studies including porosity, Darcy number. and Reynolds number on heat transfer performance have been explored in detail. The results indicate that the average local Nusselt number is augmented as the Darcy number increases. The average local Nusselt number increases as Reynolds number increases, in particular. the increase is more obvious at a higher Darcy number. In contrast. the porosity has slight influence on heat transfer. (C) 2009 Elsevier Ltd. All rights reserved