Abstract We analyzed the datasets of the flow fields at a pedestrian level around a 1:1:2 isolated block model obtained by a large eddy simulation. The purpose was to understand the effect of the block on the probability density distributions of each velocity component and wind speed, and to propose a reasonable model to predict the percentile values of wind speed (exceeding wind speeds) for the pedestrian level. The probability density distributions were skewed, especially near the block side, whereas other vicinities of the front and wake of the block did not cause significant change in the distributions. Consequently, the probability density distributions were standardized using mean and standard deviations to compare with the normal distribution. Clearly, rare wind events had an occurrence frequency of less than 10%, which shows large discrepancies from the normal distribution. Accordingly, the exceeding wind speeds for each velocity component and magnitude were determined. The exceeding wind speeds of each velocity component were poorly estimated by the mean wind speed. Nonetheless, better prediction of the exceeding wind speed of each velocity component is possible by using the peak factor. By contrast, the exceeding wind speed of the velocity magnitude is clearly proportional to the mean wind speed.

中文翻译：

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在 1:1:2 隔离块模型周围的行人水平上评估超过风速

摘要 我们分析了通过大涡模拟获得的 1:1:2 隔离块模型周围行人水平的流场数据集。目的是了解街区对每个速度分量和风速的概率密度分布的影响，并提出一个合理的模型来预测行人水平的风速（超过风速）的百分位值。概率密度分布偏斜，特别是靠近地块侧，而地块前部和尾流的其他附近没有引起分布的显着变化。因此，使用均值和标准差对概率密度分布进行标准化，以与正态分布进行比较。显然，罕见的风事件发生频率低于 10%，这表明与正态分布存在很大差异。因此，确定了每个速度分量和大小的超风速。平均风速无法很好地估计每个速度分量的超过风速。尽管如此，通过使用峰值因子可以更好地预测每个速度分量的超过风速。相比之下，速度大小的超过风速显然与平均风速成正比。