College of Civil Engineering and Architecture, China Three Gorges University, No. 8, University Road, Xiling District, Yichang 443002, China.
School of Urban Design of Wuhan University, No. 8, Donghu South Road, Wuchang District, Wuhan 430072, China.
Int J Environ Res Public Health. 2021 Nov 7;18(21):11684. doi: 10.3390/ijerph182111684.
Urban ventilation is being hampered by rough surfaces in dense urban areas, and the microclimate and air quality of the urban built environment are not ideal. Identifying urban ventilation paths is helpful to save energy, reduce emissions, and improve the urban ecological environment. Wuhan is the capital city of Hubei, and it has a high urban built intensity and hot summers. Taking Wuhan city, with a size of 35 km ×50 km, as an example, the built environment was divided into grids of 100 m × 100 m and included the building density, floor area ratio, and average building height. The ventilation mechanism of the urban built intensity index has previously been explained. The decrease in building density is not the sole factor causing an increase in wind speed; the enclosure and width of the ventilation path and the height of the front building are also influential. Twelve urban built units were selected for CFD numerical simulation. The ventilation efficiency of each grid was evaluated by calculating the wind speed ratio, maximum wind speed, average wind speed, and area ratio of strong wind. The relationship between the urban built intensity index and ventilation efficiency index was established using the factor analysis method and the Pearson correlation coefficient; building density and average building height are the most critical indexes of ventilation potential. In addition, the layout of the building also has an important impact on ventilation. A suitable built environment is that in which the building density is less than 30%, the average building height is greater than 15 m, and the floor area ratio is greater than 1.5. The urban built intensity map was weighted to identify urban ventilation paths. The paper provides a quantitative reference for scientific planning and design of the urban spatial form to improve ventilation.
城市通风受到密集城市地区粗糙表面的阻碍，城市建筑环境的小气候和空气质量并不理想。确定城市通风路径有助于节约能源、减少排放、改善城市生态环境。武汉是湖北省的省会，城市建成度高，夏季炎热。以面积为 35km×50km 的武汉市为例，将建筑环境划分为 100m×100m 的网格，包括建筑密度、容积率和平均建筑高度。城市建筑强度指数的通风机制以前已经解释过。建筑密度的降低并不是导致风速增加的唯一因素；通风路径的封闭和宽度以及前建筑物的高度也有影响。选择了 12 个城市建筑单元进行 CFD 数值模拟。通过计算风速比、最大风速、平均风速和强风面积比来评估每个网格的通风效率。使用因子分析方法和 Pearson 相关系数建立了城市建筑强度指数和通风效率指数之间的关系；建筑密度和平均建筑高度是通风潜力的最关键指标。此外，建筑物的布局对通风也有重要影响。合适的建筑环境是建筑密度小于 30%，平均建筑高度大于 15m，容积率大于 1.5。对城市建筑强度图进行加权，以确定城市通风路径。该论文为改善通风的城市空间形态的科学规划和设计提供了定量参考。
