竖向外伸肋板对高层建筑气动力特性影响的试验研究

为研究建筑外表面竖向外伸肋板对高层建筑气动力的影响，试验中采用了1个未设置肋板的参考模型和4个不同肋板布置形式的研究模型，通过模型测压风洞试验，获得了不同风向角下各模型的表面风压，进而对比分析了各模型的基底弯矩系数和层风力系数。试验结果表明：在所有试验模型中，外伸宽度d(d=7.5%D，D为模型长度)较小且靠近建筑边缘(b=15%B，b为肋板与模型边缘距离，B为模型宽度)的竖向肋板可以有效降低横风向脉动层风力系数，最大降幅为40.17%；竖向肋板可以有效降低基底弯矩系数的极值，顺风向和横风向的基底弯矩系数极值最大降幅分别为28.64%和39.02%。通过对比横风向气动基底弯矩功率谱密度发现，无肋板参考模型与加肋板模型的功率谱密度接近，说明竖向肋板的作用并非改变横风向脉动风荷载的能量分布，而是降低其强度；通过研究基底弯矩的相平面轨迹发现，当竖向肋板外伸宽度较小时，顺风向和横风向基底弯矩相关性随着竖向肋板外伸宽度的增大而增强。总体上，通过合理的竖向肋板布置能够取得较为显著的气动优化效果。

Experimental study of influence of vertical external plates on aerodynamic characteristics of high-rise buildings

In order to investigate the influence of vertical external plates on aerodynamic characteristics of high-rise buildings, one reference model with smooth facade and four models with different facade appurtenance configurations were adopted. The surface wind pressure of models under different wind directions was obtained based on pressure measurement wind tunnel test, the layer force coefficients and the base moment coefficients were subsequently compared and analyzed. The test results indicate that in all the test models, when the vertical plates are located close to the edge of the building (b=15%B,b is distance between the edge and plate, B is breadth of model) with relative small width d (d=7.5%D,D is depth of model), the across-wind fluctuating layer wind coefficient can be effectively reduced by a largest decrement of 40.17%. The vertical plates can also effectively decrease the peak value of base moment coefficients, and the largest decrements of along-wind and across-wind peak base moment coefficients are 28.64% and 39.02%, respectively. According to the power spectrum density (PSD) of across-wind base moment, it can be found that the PSD of models equipped with plates are almost identical to that of the reference model, which means that the vertical plates do not affect the energy distribution of across-wind load, but reduce its strength. The phase-plane trajectories of base moment were also examined, it is found that when the extension depth of the vertical plates is small, the correlations between along-wind and across-wind base moment coefficients tend to increase with the increase of extension width. In general, appropriate configurations of vertical plates can significantly optimize the aerodynamic force of high-rise buildings.