Scalar dispersion from ground-level sources in arrays of buildings is investigated using wind-tunnel measurements and large-eddy simulation (LES). An array of uniform-height buildings of equal dimensions and an array with an additional single tall building (wind tunnel) or a periodically repeated tall building (LES) are considered. The buildings in the array are aligned and form long streets. The sensitivity of the dispersion pattern to small changes in wind direction is demonstrated. Vertical scalar fluxes are decomposed into the advective and turbulent parts and the influences of wind direction and of the presence of the tall building on the scalar flux components are evaluated. In the uniform-height array turbulent scalar fluxes are dominant, whereas the tall building produces an increase of the magnitude of advective scalar fluxes that yields the largest component. The presence of the tall building causes either an increase or a decrease to the total vertical scalar flux depending on the position of the source with respect to the tall building. The results of the simulations can be used to develop parametrizations for street-canyon dispersion models and enhance their capabilities in areas with tall buildings.

中文翻译：

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矩形建筑物对齐阵列中高层建筑物附近的标量通量

使用风洞测量和大涡模拟 (LES) 研究了建筑物阵列中地面源的标量色散。考虑了一系列相同尺寸的等高建筑物和一个具有额外的单个高层建筑（风洞）或周期性重复的高层建筑 (LES) 的阵列。阵列中的建筑物排列整齐，形成长长的街道。散布模式对风向的微小变化的敏感性得到了证明。垂直标量通量被分解为平流和湍流部分，并评估风向和高层建筑的存在对标量通量分量的影响。在等高阵列中，湍流标量通量占主导地位，而高层建筑会增加产生最大分量的平流标量通量。高层建筑的存在会导致总垂直标量通量的增加或减少，具体取决于源相对于高层建筑的位置。模拟结果可用于开发街道峡谷分散模型的参数化，并增强其在高楼地区的能力。