Effect of Fetch on a Mechanism for Pollutant Removal from a Two-Dimensional Street Canyon
Effect of Fetch on a Mechanism for Pollutant Removal from a Two-Dimensional Street Canyon
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DOI：
10.1007/s10546-016-0136-y
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发表时间：
2016-02
影响因子：
4.3
通讯作者：
T. Michioka;H. Takimoto;H. Ono;A. Sato
中科院分区：
文献类型：
--
作者：
T. Michioka;H. Takimoto;H. Ono;A. Sato
采用大涡模拟方法，研究了建筑物高宽比为1的二维街道峡谷中，风对污染物去除机理的影响。线源被放置在第一，第二，第三，第五，第七和第十峡谷，和六个示踪气体同时释放的地面连续污染物线源平行于展向轴线放置在峡谷。峡谷内的平均浓度和浓度波动的偏差在第七个峡谷的下风处大致达到一个接近恒定的值，这与湍流强度的行为相似。在第一个峡谷中，污染物的去除受到平流和湍流的影响;然而，湍流运动主要影响污染物从峡谷顶部的去除，因为取气增加。在第一和第三峡谷中，低动量流体并不总是影响污染物的去除，但随着风的增加，这种影响逐渐增加。
Large-eddy simulation is conducted to investigate the effect of fetch on the pollutant-removal mechanism from a two-dimensional street canyon with a building-height to street-width (aspect) ratio of 1. The line sources were placed within the first, second, third, fifth, seventh and tenth canyons, and the six tracer gases are simultaneously released by a ground-level continuous pollutant line source placed parallel to the spanwise axis at the canyons. The mean concentration and the deviation of the concentration fluctuation within the canyon roughly reach a near-constant value downwind of the seventh canyon, which is similar to the behaviour of the turbulent intensities. In the first canyon, pollutant removal is affected by both advective flow and turbulent flow; however, the turbulent motions mainly affect pollutant removal from the top of the canyon as the fetch increases. In the first and third canyons, the low-momentum fluid does not always affect pollutant removal, but does so gradually as the fetch increases.