街道走向对城市交叉路口污染物扩散的影响

Effects of Orientation of Street on Pollutant Dispersion at Urban Street Intersections

结合风洞试验和计算流体力学(CFD)技术,调查了街道走向对城市街道交叉路口及其附近区域的流场以及大气污染物扩散的影响.结果显示,十字交叉路口处的气流流动和污染物扩散形态直接受到上风街道走向的影响.利用风洞试验数据对CFD方法计算浓度场的评估表明:用标准k-ε湍流模型和输送方程模拟的浓度场严重低估了烟羽的散开程度,在某些墙测点上其计算浓度小于试验值达10倍以上.

A wind tunnel and CFD investigation is carried out to study the effects of orientation of upwind street on the flow and dispersion at/or near urban street intersections. The simulations show that the flow and dispersion patterns at a street intersection are directly affected by the street orientation of the upwind street as well as flow exchange between street canyons, Comparisons of CFD simulations with wind tunnel experiments show that the under-prediction of plume spread is very serious for the k-ε turbulence model. On some wall receptors, computed concentrations are 10 times less than those measured in wind tunnel experiments.