任意排列两方形断面高层建筑风致干扰机理研究

Mechanism of wind-induced interference effects between two arbitrarily arranged square-section high-rise buildings

风致干扰效应是高层建筑群抗风设计中的常见难点问题之一。采用刚性模型测压试验,研究了均匀层流和两种大气边界层风场条件下任意排列两方形断面高层建筑的风致干扰效应,通过平均和脉动基底弯矩系数的干扰因子、风力系数、风压系数分布以及风荷载功率谱的研究,解释了其风致干扰效应的机理。结果表明,任意排列的两方形断面高层建筑风致干扰中,至少存在横风向静力干扰、顺风向静力干扰和横风向动力干扰三个值得注意的干扰区域。窄道形成的加速效应使受扰结构上形成指向施扰建筑横风向平均吸力和阻塞形成的受扰建筑的横风向平均推力;遮挡效应使得受扰建筑承受指向位于上游的施扰建筑的顺风向风力;漩涡叠加增强位于尾流区受扰建筑上的横风向脉动荷载。不同风场的试验结果表明,提高来流的紊流度有助于减弱上述干扰效应。

The wind-induced interference effect is one of the common challenges in wind-resistant design of high-rise building group. Employing the rigid model pressure test in wind tunnel,the wind-induced interference effects between two arbitrarily arranged square-section high-rise buildings were studied in a uniform flow and two atmospheric boundary layer flows. The mechanism of wind-induced interference effects was explained in term of mean value and root mean square value of base moment coefficients,wind force coefficients,wind pressure coefficient distributions and wind load spectrum. The results show that at least three interference regions,which are interference regions of cross wind static forces,along wind static forces and cross wind aerodynamic forces,should be considered in case of two arbitrarily arranged high-rise buildings. The acceleration effects in case of wind flow the narrow road between two cylinders resulted the mean across wind suctions and the blockage induced mean across wind thrust force; influenced by shielding effects,the wind force on principal cylinder is direct at the interfering building located in upstream; the vortex generated by interfering building strengthened the across fluctuating wind loads on the principal building located in wake flow. Based on results of three approaching flows,the above-mentioned interference effects are decreased with the increasing of turbulence intensity of upstream flow.