通風換気性能に関する超過確率に基づく風環境評価法の提案とその空堀モデルへの適用: 市街地の風環境に関する研究（その1）

摘要

Exceedance probability analysis was often applied as an effective method for assessing local wind environment in a street canyon, in which the effects of wind from each direction are comprehensively taken into account. In this present study, a new method by means of exceedance probabilities was proposal, with the aim to evaluate the overall ventilation performance in specific spaces within the street canyon (evaluation space), based on two ventilation indices, local air change rate and average kinetic energy, instead of using the commonly adopted wind velocity. In this method, the ventilation indices are derived from CFD simulation for each azimuth before the calculation of exceedance probability. A three-dimensional dry-area model was used as an illustration of this method. Several key factors, including orientation of dry-area, geometrical configurations, as well as statistical wind data were further investigated with the calculated distributions of exceedance probabilities.%市街地の風環境は、市街地の建物や工作物などの影響を大きく受 ける。特に人間の活動域や沿道領域といった特定の領域では、換気 効率が低下すると共に、空気環境が悪化して行く。これに対して、 市街地の上空風は市街地のラフネスの影響をあまり受けていない自 由風であり、通風換気の源（ポテンシャル）として市街地環境維持 のために大きな役割を担っている。