The influence of building height variability on pollutant dispersion and pedestrian ventilation in idealized high-rise urban areas
The influence of building height variability on pollutant dispersion and pedestrian ventilation in idealized high-rise urban areas
复制标题
理想高层城市地区建筑高度变化对污染物扩散和行人通风的影响
DOI：
10.1016/j.buildenv.2012.03.023
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发表时间：
2012-10-01
影响因子：
7.4
通讯作者：
Di Sabatino, Silvana
中科院分区：
文献类型：
--
作者：
Hang, Jian;Li, Yuguo;Di Sabatino, Silvana
仍然需要进行研究，以了解农村/海洋风如何消除高层城市地区街道网络中均匀释放的地面污染物。建筑物高度变化和污染物去除过程之间的联系仍然不清楚。首先对几个由9排和18排小规模高层方阵组成的理想化城市小区（建筑宽度B =街道宽度W，建筑密度λ（p）= 0.25）进行了数值研究，考虑了平行风和忽略热效应。采用归一化污染物输运率和行人净化流量，定量分析了平均流和湍流扩散对污染物去除的贡献及其净净化能力。结果表明，等温湍流流动的预测与风洞试验数据基本吻合。对于建筑物高度变化（标准差为0-573%）和相同平均冠层高度（H-0 = 2.33W）的9行阵列，污染物去除主要取决于平均流量。较大的标准差往往会导致更好的行人通风。与小标准差和大标准差相比，14.3-42.9%的中间值可能会经历水平平均流量的较小吹扫能力，但会显著增强垂直平均流量的吹扫能力。对于高度均匀的阵列，降低纵横比（H/W = 2.33和2.67-1.5）或增加街道长度（9行到18行）可能会增加通过跨冠层屋顶的湍流扩散去除污染物的贡献，这可能与平均流同样重要。虽然还需要进一步的调查，本文阐明了建筑布局，高度变化和地面污染物的去除潜力之间的关系，在高层城市的几何形状。(C)2012爱思唯尔有限公司保留所有权利。
Studies are still required to understand how rural/marine wind remove ground-level pollutants released uniformly in street networks of high-rise urban areas. The link between building height variability and pollutant removal process still remains unclear. Several idealized urban-like neighbourhoods made of 9-row and 18-row small-scale high-rise square arrays (building width B = street width W, building packing density lambda(p) = 0.25) were first numerically studied with a parallel approaching wind and neglecting thermal effects. Normalized pollutant transport rates and pedestrian purging flow rate were applied to quantify the contribution of pollutant removal by mean flow and turbulent diffusion and their net purging capacity. Results show that the prediction of isothermal turbulent flows agreed generally well with wind tunnel data. For 9-row arrays with building height variations (standard deviation of 0-573%) and the same average canopy height (H-0 = 2.33W), pollutant removal mainly depends on mean flows. Larger standard deviations tend to induce better pedestrian ventilation. In comparison to small and large standard deviations, medium values of 14.3-42.9% may experience smaller purging capacity by horizontal mean flows but significantly enhance that by vertical mean flows. For arrays with uniform heights, lowering aspect ratios (H/W = 2.33 and 2.67-1.5) or increasing street lengths (9-row to 18-row) may enhance the contribution of removing pollutants by turbulent diffusions across canopy roofs which may be similarly important as that by mean flows. Although further investigations are still required, this paper clarifies the relationship between building layouts, height variability and removal potential of ground-level pollutants in high-rise urban-like geometries. (C) 2012 Elsevier Ltd. All rights reserved.