城市高架道路对局地大气环境影响的数值模拟研究

根据城市高架和街道的布局与几何特点,设计了多种典型的街道峡谷模型。应用k-ε湍流模型和污染物浓度扩散方程,采用数值模拟技术预测了这些带高架的城市街道峡谷内湍流流场和污染物浓度场。研究表明,高架道路的存在改变了街道峡谷内大气的流动结构和汽车排放污染物的传输扩散特性。高架道路空间位置的布设及高架与街道建筑物间的间隙,对城市街道峡谷的局地大气环境有显著影响。因此,在确定布设高架位置和设计规划街道布局时,应尽量避免引起“盖子效应”而造成严重的地面局地大气污染。

Numerical Study on Impact of Urban Viaduct on Local-Scale of Atmospheric Environment

Several typical models of urban street canyons were presented according to the layout and geometry of the viaduct and street in Shanghai. The numerical modeling method has been used to predict the flow and dispersion of these models of street canyons by solving the k- e turbulence model and the pollutant diffusion equations. It showed that the different characteristics of atmospheric flow and pollutant dispersion of vehicle emissions has taken place from the original street canyon due to the presence of the viaduct. The variable locations of the viaduct and distances from buildings to the viaduct impacted obviously on the local-scale atmospheric environment. Thus the case that may bring the "cover domino effect" due to ill-suited location of viaduct and street layout should be avoided while designing the viaduct locations and street layout.