Hadavand - Graduated, Shiraz University Shiraz, Iran
Yaghoubi - Professor, Shiraz University Shiraz, Iran
Emdad - Assistant professor, Shiraz University Shiraz, Iran

Domed and vaulted roofs buildings have been the mostimportant part of architecture in the middle-east area and specially in Iran. These kinds of roofs have shownstrong natural ventilation and also they have adequateprotection against the wind storms in hot desert climate of IranIn this study attempt is made to evaluate transient heattransfer of a two dimensional vaulted roof and flat rooffor different rim angles, widths of buildings and variouswind flow conditions. Turbulence is modeled by RNGk-ε scheme and solar radiation distribution over the roofis determined based on an appropriate model applicableto hot arid regions of Iran. It was found that wind flowover various vaulted and flat roofs make substantialdifferences on flow field, convection heat transfer coefficient and finally on heat flow of building. For larger width of flat and vaulted roof building, heatflux to the room decreases slightly as compared of those lower widths.

RNG k-ε turbulence model، Solar radiation، Vaulted roof، Passive cooling