论文部分内容阅读
为减少高层建筑受到的风荷载,提高高层建筑抗风性能,提出一种顶部吸气的主动控制方法。在一高宽比为H/d=5的正方形截面柱体的高层建筑模型上,通过在其顶部前边缘开设狭缝进行吸气来实现流动控制。通过风洞试验研究了顶部吸气对气动力与顶部分离流的影响.利用流动可视化与流场测试结果揭示了顶部狭缝吸气的控制机理.实验对比了不同吸气系数Q(=U/U_∞,U为狭缝吸气速度)对气动力控制效果的影响,并对Q=0,1和3的三种工况下风压分布与顶部剪切流进行了详细对比.研究发现狭缝吸气改变了顶部分离流特性,并对模型所有高度上的气动力均有显著影响.Q=1时控制效果最佳,脉动阻力与脉动升力分别减小17.8%和45.5%.此时顶面分离流被削弱并伴随有再附现象且湍流强度较大,最有利于顶部剪切流与尾流间的动量交换,从而削弱柱体展向涡脱落与脉动气动力.
In order to reduce the wind load on high-rise buildings and improve the wind-resistance performance of high-rise buildings, an active control method of top suction is proposed. On a high-rise building model with a square cross-section cylinder with an aspect ratio of H / d = 5, flow control is achieved by opening a slit in the top front edge to inspiratory. The effect of top suction on aerodynamic force and top separation flow was studied by wind tunnel test.The control mechanism of top slot suction was revealed by flow visualization and flow field test results.Experiments were carried out to compare the different suction coefficients Q (= U / U_∞, U is the suction speed of the slot) on the aerodynamic control effect, and the wind pressure distribution and the top shear flow under three conditions of Q = 0, 1 and 3 are compared in detail.It is found that the slit Inhalation changed the characteristics of the top separation flow and had a significant effect on the aerodynamic forces at all altitudes of the model. The control effect was best at Q = 1, and the pulsation resistance and pulsating lift were reduced by 17.8% and 45.5% respectively. The separation flow is weakened and accompanied by the phenomenon of reattachment and turbulence intensity is most conducive to the momentum exchange between the top shear flow and the wake, thus weakening the vortex shedding and pulsating aerodynamic forces.