论文部分内容阅读
对带有隔声屏障的街道峡谷内流场和污染物浓度场进行了数值模拟,探讨了风速、隔声屏障高度及与建筑物间的距离对流场及污染物扩散的影响。模拟结果显示:街谷内由1个稳定的主涡及街角两侧隔声屏障所在区域的3个附属涡组成。隔声屏障改变了街谷底部的流型,提高了街谷内的x、y方向速度峰值,但在隔声屏障附近区域x方向速度场明显减弱,这也是污染物聚集原因之一。与无隔声屏障相比,隔声屏障的存在物理性阻隔了污染物扩散路径,提高了街道峡谷内污染物浓度峰值,其中行人高度处背风面污染物浓度升高27.51%~28.72%,迎风面污染物浓度升高11.64%~19.99%。街谷内污染物浓度的分布和峰值由风场、隔声屏障高度及与建筑物之间的距离共同决定。
The numerical simulation of flow field and pollutant concentration field in street canyon with sound barrier is carried out. The effects of wind speed, height of sound insulation barrier and the distance between buildings on the flow field and pollutant diffusion are discussed. The simulation results show that the street valley consists of three main vortices and three appendices in the area where the noise barriers on both sides of the street corner are located. The noise barrier changed the flow patterns at the bottom of the street valley and increased the peak velocity in the x and y directions in the street valley. However, the velocity field in the x direction near the noise barrier significantly decreased, which was also one of the reasons for the pollutant accumulation. Compared with no noise barrier, the presence of noise barrier physically obstructs the diffusion path of pollutants and increases the peak concentration of pollutants in street canyons. The concentration of pollutants on the leeward side of pedestrian height is increased by 27.51% -28.72% Surface contamination increased by 11.64% ~ 19.99%. The distribution and peak value of pollutant concentrations in street valleys are determined by the wind field, the height of the noise barrier and the distance from the building.