Urban crossings are important component of the cities. Creating thermal comfort especially in the marginal cities of the deserts could improve the life quality. How we can solve this problem effectively? By natural wind flow. The block formation of buildings in urban crossings are different in traditional and modern contexts. In Kashan, a city in Iran, as our case study, the building blocks formation are divided into 4 general categories: 1) Completely traditional context: often central yard, 7-meter height 2) Semi- traditional context: some of newly build building, one side built, at last 7.5-meter height (according to the existing rules.) 3) Urban new context with non-ordered routes: different heights, at last 5 floors. 4) Urban new context with ordered axis: the same heights for the buildings, from 3 to 6 floor, more than 6 floors in some cases. The current research question is that what is the difference between the block formation of buildings in Kashan, Iran for modern and traditional context in confronting natural wind flow and air flow in urban crossings and which one has more thermal comfort? Research tools are based on the newest maps of Kashan, Iran to investigate different plaques of different parts (traditional and modern) and the differences of wind flow formation and have an effect on creating thermal comfort of the urban outdoors. Research tools are CFD like Ansys Fluent and Autodesk CFD and making maquettes and doing test in wind tunnel in order to simulate natural air flow. Finally, a comparative study showed the effect of different forms of urban contexts on thermal comfort and help to propose the utilized block form. Finally, a comparative study showed the effect of different forms of urban contexts on thermal comfort.
