Driving physical mechanisms of flow and dispersion in urban canopies
Driving physical mechanisms of flow and dispersion in urban canopies
复制标题
驱动城市冠层流动和分散的物理机制
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
M. Schatzmann
中科院分区：
文献类型：
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作者：
P. Klein;B. Leitl;M. Schatzmann
本文总结了最近的全尺寸和风洞研究的结果，并讨论了城市冠层（UCL）流动的复杂性和城市建模的相关挑战。理想化街道峡谷交叉口的风洞数据表明，对于建筑物高度不均匀的结构，街道水平流和扩散模式会发生显著变化。对于大多数风向，浓度最大值高达2倍的情况下，较高的建筑物附近的交叉口。高层建筑物尾流中增强的垂直向下混合显然会导致附近街道水平风更高，但同时，其他区域会受到积极混合和通风不良的保护。对Joint Urban 2003（JU2003）全尺寸数据的分析还指出，高动量流体可以有效地混合在高层建筑的尾流中，并且UCL流主要由屋顶风动态驱动。因此，建筑物高度的可变性是UCL动态和混合的关键因素。
The paper summarizes results from recent full‐scale and wind‐tunnel studies and discusses the complexity of urban canopy layer (UCL) flow and related challenges for urban modeling. Wind‐tunnel data for idealized street‐canyon intersections demonstrate that street‐level flow and dispersion patterns are significantly altered for configurations with non‐uniform building heights. For most wind directions, concentration maxima were upto a factor of 2 higher for cases with taller buildings near the intersection. Enhanced vertical downward mixing in the wakes of the taller buildings apparently causes higher street‐level winds close by, but simultaneously, other regions become sheltered from active mixing and poor ventilation. The analysis of Joint Urban 2003 (JU2003) full‐scale data also pointed out that high‐momentum fluid can be effectively mixed down in the wakes of high‐rise buildings, and that UCL flow is predominantly dynamically driven by roof‐level winds. Building‐height variability is thus, a key factor for UCL dynamics and mixing.