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

Abstract

The main aim of the study is to investigate passive cooling performance in modern urban contexts in the hot humid climate of the city of Dubai. Three cases were simulated for Al-Mankhool area with laminar and turbulent windflow depending on Computational Fluid Dynamics (CFD) methodology. The laminar case was firstly run to study the general wind behaviour around buildings and at the pedestrian level. The other two cases were turbulence modelling in both winter and summer seasons. The results were merely discussed and analysed in terms of passive cooling via natural ventilation and its impact on human comfort depending on the ASHRAE adaptive model. In the modern urban pattern, wind flow decreased when hitting the buildings, funnelled by the wider street canyons, then increased once again when going to the free stream. Wind velocities were more comfortable in wider street canyons with aspect ratio, AR = 1.75. It was noticed that wind speed increased substantially in open spaces such as parking areas and undeveloped plots reaching its maximum values of 4.55 m/s in the summer and 5.06 m/s in the winter. Where as in the longer street canyons bounded by building blocks on opposite sides, the wind velocity remained stable at low values (0.51 m/s in the winter versus 1.52 m/s in the summer) with limited fluctuation till it joined the free stream again.