螺旋线对斜拉索涡激振动特性影响的试验研究

Experimental Study on Influence of Helical Lines on Vortex-induced Vibration Characteristics of Stay Cables

为研究不同参数的螺旋线对斜拉索涡激振动特性和气动力的影响规律,进行了针对表面无螺旋线斜拉索和缠绕不同参数螺旋线斜拉索的节段模型风洞试验,螺旋线参数包括根数、直径和缠绕间距.结果表明:斜拉索表面缠绕1根螺旋线的涡激振动振幅远大于2根或3根螺旋线;在亚临界雷诺数区,缠绕螺旋线斜拉索的平均气动阻力系数均小于无螺旋线斜拉索,最多可减小10.9%;缠绕2根螺旋线的斜拉索平均阻力系数整体比3根螺旋线小.斜拉索表面缠绕间距s=8D(D为斜拉索直径)的2根螺旋线时,缠绕直径d<15 mm螺旋线的斜拉索涡激振动现象明显;d≥15 mm的螺旋线可显著降低斜拉索涡激振动响应幅值,其脉动升力系数相较于无螺旋线斜拉索有明显降低,证明缠绕大直径螺旋线对涡激振动响应控制的有效性.螺旋线的缠绕间距对斜拉索涡激振动的影响与螺旋线直径有关,当螺旋线直径较小时,缠绕间距对涡激振动的影响并不明显;当螺旋线直径较大时,间距的大小直接影响涡激振动的抑制效果.

To study the influence law of helices with different parameters on the Vortex-induced Vibration(VIV)characteristics and aerodynamic force of stay cables,the wind tunnel test of a section model was carried out for smooth cables and those with helices.The helix parameters include number,diameter,and winding spacing.The results show that the VIV amplitude of one helix wound on the surface of the stay cable is much larger than that of two or three helices.In the subcritical Reynolds number region,the mean drag coefficient of the stay cable with two helices is smaller than that of the smooth cable,which can be reduced by 10.9%at most.The mean drag coefficient of stay cable with two helices is smaller than that with three helices.When the stay cable is wound with two helices with s=8D,the VIV of the stay cable wound with d<15 mm is obvious.The helix with d≥15 mm can effectively reduce the amplitude of the VIV,and its fluctuating lift coefficient can be reduced obviously compared with the smooth cable,which proves the effectiveness of the winding large-diameter helices in controlling the VIV response.The influence of the winding spacing on the VIV of the stay cable is related to the diameter of the helices.When the diameter is small,the influence of the winding spacing on the VIV is not marked.When the diameter is large,spacing directly affects the suppression effect of VIV.