Numerical simulation for cross-ventilation flow of generic block sheltered by urban-like block array
Numerical simulation for cross-ventilation flow of generic block sheltered by urban-like block array
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DOI：
10.1016/j.buildenv.2020.107174
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发表时间：
2020-11
影响因子：
7.4
通讯作者：
Y. Adachi;N. Ikegaya;H. Satonaka;A. Hagishima
中科院分区：
文献类型：
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作者：
Y. Adachi;N. Ikegaya;H. Satonaka;A. Hagishima
本研究报告的结果大涡模拟与标准Smagorinsky模型的速度场内的交叉通风模型遮挡块阵列。采用了建筑高度1/100的非常精细的分辨率。目的是了解周围建筑阵列的遮蔽效果，并量化交叉通风模型中的通风率。模拟了两种类型的块阵列和开口位置。数值计算和实验结果的比较证明，目前的模拟再现的平均值，以及在通风模型中引入的湍流的特性。此外，室外和室内的速度的同时观察使我们能够得出结论，在室外的流动模式的变化引起了室内的速度分布的显着变化，虽然在所有这些情况下的开口位置是相同的。使用这些详细的流场，我们比较了三种类型的通风率：净，毛，瞬时通风率。此外，我们估计的瞬时通风率使用一个随机变量的高斯分布。由于湍流流入的通风是至关重要的，在模型中，其开口的侧面上的块，而平均流量主要决定了通风率的块，其开口的流向的墙壁。在这两种情况下，估计模型可以很好地预测瞬时通气率，最大高估只有3%。这意味着该模型在所有当前阵列和开口条件下都是合理的。
This study reports the results of large eddy simulations with the standard Smagorinsky model of the velocity fields within a cross-ventilation model sheltered by block arrays. A very fine resolution of 1/100 of the building height was adopted. The objectives are to understand the sheltering effect of the surrounding building array and quantify the ventilation rate in the cross-ventilation model. Two types of block arrays and opening positions were simulated. Comparisons of the numerical and experimental results justify that the present simulations reproduced the characteristics of the mean as well as turbulent flows introduced in the ventilation model. In addition, the simultaneous observations of the outdoor and indoor velocities enabled us to conclude that the change in the outdoor flow patterns caused a dramatic change in the indoor velocity distributions, although the opening position was identical in all such cases. Using these detailed flow fields, we compared three types of ventilation rates: the net, gross, and instantaneous ventilation rates. Moreover, we estimated the instantaneous ventilation rate using a random variable following the Gaussian distribution. The ventilation due to the turbulent inflow was crucial in the model with its opening on the lateral side of the block, whereas the mean flow primarily determined the ventilation rate for the block with its opening on the streamwise walls. In both cases, the estimation model could predict the instantaneous ventilation rate well with a maximum overestimation of only 3%. This means that the model was justified for all the present array and opening conditions.