Outdoor airflow analysis and potential for passive cooling in the traditional urban context of Dubai

Abstract

The main aim of the study is to investigate passive cooling performance in traditional urban contexts in the hot humid climate of the city of Dubai. Three cases were simulated for Al-Ras area with laminar and turbulent wind flow depending on Computational Fluid Dynamics (CFD) methodology. The laminar case was firstly run to study the general wind behavior around buildings and at the pedestrian level. The other two cases were turbulence modeling in both winter and summer seasons. The results were merely discussed and analyzed in terms of passive cooling via natural ventilation and its impact on human comfort. Narrow street canyons (4 m and less) can accelerate wind speed passing through it, resulting in a better passive cooling performance but sometimes in creating eddies if there are lots of bending angles. When the wind speed is higher (5 m/s), wind can reach deeper inside the traditional narrow streets providing better potential for thermal comfort. Most locations (49–57% of the studied area) inside the traditional urban context (street canyons aspect ratio, AR = 2–0.67) have wind speeds that range from light breeze to gentle breeze (according to Beaufort scale); which has the potential to provide natural cooling with around 5–8.5 °C lower temperature comfort sensation with basic assumption of 1.3 metabolic rate (MET) and 0.4 insulating value of summer clothing (CLO).