Effect of Incoming Turbulent Structure on Pollutant Removal from Two-Dimensional Street Canyon
Effect of Incoming Turbulent Structure on Pollutant Removal from Two-Dimensional Street Canyon
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DOI：
10.1007/s10546-012-9733-6
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发表时间：
2012-05
影响因子：
4.3
通讯作者：
T. Michioka;A. Sato
中科院分区：
文献类型：
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作者：
T. Michioka;A. Sato
采用大涡模拟方法研究了来流湍流结构对理想峡谷污染物去除的影响。目标峡谷是纵横比为1.0（建筑物高度与街道宽度）的二维街道峡谷。三个湍流上风的街道峡谷是通过使用不同的块配置产生的，和示踪气体被释放作为地面水平线源在中心的峡谷地板。三种流动的平均速度剖面相似，除了靠近屋顶。然而，均方根值的速度波动和雷诺剪应力的增加与摩擦速度的到来湍流。峡谷内的空间平均浓度随着摩擦速度的增加而降低。低动量流体的相干结构，产生以上的迎风块配置，有助于污染物的去除，和污染物的去除量是直接相关的相干结构的大小。
Large-eddy simulations are conducted to investigate the effects of the incoming turbulent structure of the flow on pollutant removal from an ideal canyon. The target canyon is a two-dimensional street canyon with an aspect ratio of 1.0 (building height to street width). Three turbulent flows upwind of the street canyon are generated by using different block configurations, and a tracer gas is released as a ground-level line source at the centre of the canyon floor. Mean velocity profiles for the three flows are similar, except near the roof. However, the root-mean-square values of the velocity fluctuations and the Reynolds shear stress increase with the friction velocity of the incoming turbulent flow. The spatially-averaged concentration within the canyon decreases with increasing friction velocity. Coherent structures of low-momentum fluid, generated above the upwind block configurations, contribute to pollutant removal, and the amount of pollutant removal is directly related to the size of the coherent structure.