Abstract
The present study is carried out to investigate the effect of radiation and viscous dissipation in a square porous annulus subjected to outside hot T-h and inside cold T-c temperature. The square annulus has a hollow section of dimension DxD at the interior of annulus. The flow is assumed to obey Darcy law. The governing equations are non-dimensionalised and solved with the help of finite element method. Results are discussed with respect to viscous dissipation parameter, radiation parameter and size of the hollow section of annulus.