基于片状激光-CCD浓度测试系统研究屋顶形状对街谷内污染物扩散的影响

基于风洞实验平台,利用研发的片状激光-CCD浓度测试系统结合数值模拟,研究不同屋顶形状对街道峡谷内线源污染物扩散分布的影响。结果表明,采用的浓度测试系统可以在不影响流场的情况下清晰再现街道峡谷内部污染物分布的特征,并且测试结果与数值仿真结果有较好的一致性。当迎风建筑屋顶低于背风建筑屋顶时,街谷内为一顺时针主涡,污染物主要聚集在街谷背风侧;迎风建筑屋顶高于背风建筑时,街谷内形成顺时针旋涡在上、逆时针旋涡在下的两个耦合旋涡,此时污染物在街谷迎风侧聚集。

The effect of roof shape on pollutant diffusion in the street canyons based on laser sheet-CCD concentration testing system

Based on wind-tunnel measurements with the laser sheet-CCD concentration testing system and numerical simulation,the influence of different roof shapes on the pollutant distribution in the street canyons was studied.Results showed that the characteristics of pollutant distribution can be clearly reproduced by the developed concentration testing system without affecting the flow field.The test results agreed well with the numerical simulations.When the roof of the windward building is lower than the leeward building,a clockwise main vortex formed in the street canyon,and the pollutants mainly gather near the leeward side of the street.When the roof of the windward building is higher than the leeward building,there are two coupled vortices in the street canyon,one clockwise vortex in the upper and one anticlockwise vortex below,and the higher level of the pollutant concentration appeared on the leeward side of the street canyon under this case.