Prediction of building surface concentration profiles by empirical for mulas considering the effects of oncoming flow profiles on concentration fields

本课题提出了在孤立的高层建筑附近估算点源时建筑物表面浓度剖面的计算方法。提出的方法采用垂直浓度曲线的衰减指数代替基于高斯羽流概念的扩散宽度。该指数是由实验结果得出的，垂直浓度分布与建筑物表面上点源与采样口之间的距离成反比。经验公式可以预测建筑物表面浓度的垂直分布，当点源位于建筑物上游时，平均预测误差为35%，而在空腔区域，平均预测误差为14%。当不能很好地估计最大浓度位置时，预测精度会降低。

This project developed the calculation methods for estimating building surface concentration profiles when point sources were located near an isolated high-rise building. The proposed methods used a decay index of vertical concentration profiles as substitutes for diffusion widths based upon Gaussian plume concepts. The index was derived from the experimental results that the vertical concentration profiles were inversely proportional to the power of the distance between point sources and sampling ports on the building surfaces. The empirical formulas could predict the vertical profiles of building surface concentrations with a mean prediction error of 35% when point sources were located upstream from the building and 14% for the cavity region. The prediction accuracy became worse when the location of maximum concentrations could not be estimated well.