日光照射对街道峡谷污染物扩散影响的研究

为了分析日光照射对城市街道峡谷机动车污染物扩散的影响．对街道峡谷日光照射的物理模型进行了简化．采用数值模拟技术对日光照射下的城市街道峡谷内气体流动和机动车污染物扩散规律进行了研究。结果表明．在一定条件下。日光照射是研究城市街道峡谷内污染物扩散必须考虑的因素。在污染物扩散受日光照射影响较大的街道峡谷内部．当街道地面或迎风面受日光照射时．街道峡谷内部将出现2个方向相反的漩涡，并导致迎风面建筑物一侧的污染物浓度升高．这与不计日光照射的特征有显著的不同。

Study on Effect of Sunlight on Pollutant Dispersion in Street Canyon

In order to predict the impact of sunlight on vehicle's pollutants dispersion in street canyon, an investigation has been conducted to evaluate fluid flow and pollutant dispersion by numerical simulation. In this paper main fluid flow and pollutant dispersion in street canyon were resolved by numerical method. The study result showed that sunlight played a great role on fluid flow and pollutant dispersion in street canyon under certain conditions. When sunlight fell on the street bottom or windward building of street canyon, two contra-direction vortexes occurred within street canyon and caused that windward building held a higher pollutant concentration which was clearly different from the situation of same street canyon without sunlight