EVALUATION OF VENTILATION PERFORMANCE IN VOID SPACE BY EXCEEDANCE PROBABILITIES BASED ON CFD SIMULATION

In this present study, annual exceedance probability (AEP) analysis was applied as the method forassessing wind-driven natural ventilation in a street canyon, in which the effects of wind approachingfrom each direction were comprehensively taken into account. In order to evaluate the overallventilation performance in specific domain spaces within the street canyon, local air change rate andaverage kinetic energy were employed to calculate the AEP, instead of using the commonly adoptedvelocity ratio. Thus, two domain-oriented AEPs, local air change rate-based AEP and local kineticenergy-based AEP, were proposed with the local air change rate and average kinetic energy of the voidderived from CFD simulation. A three-dimensional symmetric model including three parallel canyonswas used as an illustration to analyze the distributions of AEPs by using the statistical wind data fromthe Tokyo Meteorological Observatory. The simulation results indicated that the most favorableorientation is East and the most adverse is North-North-East for a canyon model located in theurban Tokyo area. The influences of width on ventilation efficiency were also investigated by using thedistributions of AEPs.