超高层建筑横风向风振局部气动外形优化

Effect of aerodynamic optimization to across-wind response of super tall buildings

为了研究局部气动措施对方截面超高层建筑横风向风振的控制效果,开展大量的多自由度气弹模型风洞实验,测量模型在多种切角率、圆角率、粗糙条及开洞方式下的横风向风致位移响应,对横风向位移进行对比分析.结果表明:当切角率大于5%或圆角率大于15%时,横风向风致位移响应显著降低,位移均方根随折算风速的变化曲线接近直线而不再呈倒"V"字形,说明涡激共振发生的可能性得到了有效抑制;切角率或圆角率越大,横风向位移响应的减小幅度越显著;特定粗糙条的设置可以使涡振响应幅值降低20%以上;通风洞不论是垂直于来流还是平行来流,都会使涡振响应幅值减小,且洞口在中上部时的效果最佳.整体来看,局部气动外形控制措施具有显著的抗风优化效果.

Wind tunnel tests of multi-degree-of-freedom （MDOF） aero-elastic model were conducted in orderto analyze the influence of aerodynamic modifications on across-wind response of super high-rise buildingswith square section. The across-wind displacements of the models with various chamfering ratio,rounding ratio, openings and roughness were measured. Results showed that the vortex-induced vibration（V IV ） displacements were significantly decreased when the chamfering ratio was larger than 5 % or therounding ratio was larger than 1 5 % . Under these conditions, the V IV RMS displacements were almost linearwith reduced wind speed. The response level decreased with increasing chamfering ratio or rounding ratio, which means the possibility of vortex induced resonance phenomena was decreased. The setting of thespecific rough can reduce the amplitude of the vibration response of the vortex by more than 2 0 % . Theopenings can make the vortex vibration response amplitude decrease, especially when the opening is locatedat the middle of the model. In summary,aerodynamic optimization is an efficient way to control the vortexinducedvibration of super-tall buildings.