上游干扰作用下高层建筑迎风面风压双峰分布特征数值模拟研究

Numerical simulation of bimodal-distribution featured wind pressure on windward side of high-rise building influenced by interference effects

在上游建筑干扰作用下,受扰高层建筑迎风面部分测点表现出正负压交替出现的现象,对应风压系数概率密度函数呈双峰分布特征。采用大涡模拟技术对上述现象进行数值模拟研究,并将模拟结果与风洞试验结果进行对比分析,以验证其有效性。研究结果表明,上游施扰建筑两侧的尾流脱落旋涡可演变成交替作用于受扰建筑迎风面的涡团,这些涡团与背景来流共同作用,在建筑表面形成正负压交替出现的风荷载。针对风压双峰分布特征,建立风压信号混合分布模型,该混合模型由与正压成分对应的高斯分布模型和与负压成分对应的广义极值分布模型组成,模型中的位置参数、尺度参数和权重都对整体风压分布特征有显著影响。相关研究可用于非高斯风压信号的极值评估及建筑围护结构风致破坏机理的分析。

Owing to the interference effect of upstream buildings, the wind pressure at some taps on the windward side of the studied building is found to consist of both positive and negative pressure components that occur alternately, and the corresponding probability-density-function(PDF) of pressure signal demonstrates a bimodal distribution feature. Numerical studies are conducted on the above phenomena by using large-eddy-simulation(LES) techniques. The simulation results are then compared with those observed from wind tunnel tests for validation purposes. Results show that the negative pressure components are associated with vortexes that shedalternately from the two sides of the upstream building, while the positive pressure components are associated with background wind flows. A mixture PDF model has been proposed to quantify the bimodal distribution of wind pressure. The mixture model involves two parts: the Gaussian distribution part which corresponds to the positive pressure component and the generalized-extreme-value(GEV) distribution part which corresponds to the negative pressure component. The position parameter, scale parameter, and weight parameter of the model are found to have significant influence on the distribution features of wind pressure. The presented study provides new insights for evaluating the extreme values of non-Gaussian wind pressure;it can also enrich the mechanisms for wind-induced damage to curtain walls.