Evaluation of Local Wind Environment in a Dense Building Block Based on Exceedance Probability Analysis Method

This paper is devoted to study wind environment in a dense urban areas from the ventilation perspective. In order to take the stochastic characteristics of city wind into consideration, the exceedance probability analysis method was applied using air change rate as the index. The air change rate in the target domain was first obtained using CFD simulation for 16 wind directions and each building pattern. The CFD results demonstrated that airflow fields in the target domain were complicated and the air change rates depends greatly on wind direction. However, there is no direct correlation between street width and air change rate. The exceedance probability distributions were further calculated using the wind statistical data in Tokyo and used to analysis the influences of model orientation and street width. The results indicated that both factors affects the ventilation performance in the target domain significantly. The proposed evaluating approach is useful and effective for the urban ventilation design.