New criteria for assessing local wind environment at pedestrian level based on exceedance probability analysis

In this present study, the wind environment was evaluated for local void domain at pedestrian level in the aspect of ventilation performance and thermal comfort. Exceedance probability analysis was applied as the main approach in order to estimate the uncertainties associated with the influence of climate on wind environment. Two criteria were proposed based on local air change rate and local kinetic energy respectively, which are domain-based indices allowing comprehensive estimation of local wind environment. Calculating output of these criteria in the form of cumulative distribution function forms a ground for reliability analysis of inadequate ventilation or thermal discomfort. A simple street canyon situated in Tokyo, defined as void model, was applied as an illustration of the new criteria in evaluating the local wind environment at ground level. The influences of two configuration factors: orientation and aspect ratio of the void model were investigated by CFD simulation. The results demonstrated that both factors show great influences on local ventilation performance, which also indicated the practicability and effectiveness of the proposed criteria to help achieving good wind environmental design.