Analysis of combined natural convection and thermal radiation heat transfer in a triangular shaped roof for hot climates

The roofs play an important role in the energy performance of building. in the present study,natural convection with surface radiation heat transfer is investigated numerically in a triangular shaped roof with eave (gabel roof) for hot climates. a specifically developed numerical model,based on the finite-volume method,is used for the solutions of the governing differential-equations. the simpler algorithm was adopted for the treatment of velocity-pressure coupling. concerning the radiation exchange,we consider that the fluid (air) is transparent,so only the solid surfaces contribute to the radiation exchange and assumed to be diffuse-gray. the key parameters for this analysis are considered as rayleigh number (ra),aspect ratio (a) and eave lengths (e*). results are reported in terms of isotherms,streamlines and local and average nusselt numbers.