Field measurement and numerical simulation of the relationship between the vertical wind environment and building morphology in residential areas in Xi'an, China.

The inadequate consideration of the impact of building morphology on ventilation efficiency in many urban residential areas has resulted in a series of environmental problems that threaten human health. The purpose of this paper is to establish a predictive model between ventilation efficiency and building forms in residential areas. First, the characteristics of the vertical wind profile in residential areas were measured using unmanned aerial vehicle (UAV). Second, the wind speed ratio (WSR) at different height levels under the impact of morphological index (floor area ratio, building density, average building height, enclosure degree, height fall, and maximum building height) in the residential area was simulated by ENVI-met. Two kinds of prediction formulas were finally obtained: (1) the average ventilation efficiency at the pedestrian level and (2) the prediction formula of WSR at different heights. The results show that the wind speed (WS) in residential area below 35 m is about 0.6 m/s lower than that in green park. The numerical simulation shows that the mean WSR at the pedestrian level is negatively correlated with each index, and the height fall morphological index has the largest impact on the WSR at different heights. The research provides a reference for the optimal planning and design of ventilation efficiency of residential buildings, especially those in static wind areas.