都市環境気候図作成のための街路空間の風環境評価に関する研究

摘要

本研究では，大阪市を対象として街路空間内の風環境をCFDにより計算し，その結果と街区の形態を示す特性値との関係を分析し，都市環境気候図作成のために，街路空間の平均的な風環境に対して支配的なパラメータを考察した.250m四方以上で平均した空間平均風速は，ダロス建蔽率を用いるよりオープンスペース率を用いる方がより説明されやすいと考察された.この理由は，グロス建蔽率が30％以上になると空間平均風速との関係が確認されなくなるためであり，オープンスペース率は空間平均風速に対してより直接的な指標であるといえる.%Ventilation in street canyons contributes to mitigation of extremes in the thermal environment in urban areas. In previous studies, a strong relationship between the gross building coverage ratio and the spatial average wind velocity at pedestrian level has been confirmed.In this study, the relationship between wind environment and street canyon characteristics was analyzed using CFD and a GIS tool. Spatial average wind velocity is explained better by the open space ratio rather than the gross building coverage ratio in grids more than 250 m square grid. It means that the open space ratio is more direct indicator to spatial average wind velocity. Spatial average wind velocity averaged in the area of about 250 to 1,250 m square grid is meaningful. In this scale, it is possible to extract the typical characteristics of wind environment in the street canyon. When the evaluation scale is less than 10 m square, the wind environment in street canyons is best evaluated by more specific indicators (e.g., building height and road width) rather than spatially averaged indicators.