波浪型斜拉索涡激振动实验研究

针对目前改变斜拉索表面形状来抑制斜拉索由风载荷引起的振动所遇到的问题,采用热线风速仪、激光位移器测量和烟线等实验方法,实验研究在Re=6 800~20 480区域内波浪型斜拉索涡致耦合振动及频率"锁定"现象,并引入直斜拉索作为对比。实验表明:在相同的质量比和阻尼比下,波浪型斜拉索λ/D=2和λ/D=6同直斜拉索同样容易被诱导振动,波浪型λ/D=2比波浪型λ/D=6的减震效果要好,和直斜拉索相比,波浪型λ/D=2的诱导振动时最大振幅减小10%,锁定区间变短,主要是由于随着表面凹凸变化倾斜度较大,波浪型斜拉索表面的展向二次涡强度得以增强,一旦诱导振动,将干扰斜拉索的涡旋激励,从而达到减震的目的。

Experimental Study on the Vortex-induced Vibration ofWavy Stay Cabl

Considering the existing challenges of the flexible stay-cable vibration control under the wind load and wing-rain load, we proposed a new modified wavy stay-cable to suppress the vibration and reduce the drag. By using hot-wire anemometer, Laser displacement sensor, pressure scanning valve, smoke wire and other experimental methods, we studied the vortex-induced vibration(VIV) and Lock-in phenomenon of the wavy stay cable at Re=6800-20480 and the regular stay cable was introduced for comparison. The experimental results indicated that at the same mass ratio and damping ratio, the wavy stay cable with and can also be induced to vibrate as same as straight stay cable, the vibration suppression of wavy stay cable still be existed, the wavy stay cable with is better than wavy stay cable with . Compared with straight stay cable, the vibration suppression is up to 10% with shorter “lock-in” region. One of the main reasons is the large variation of modified wavy stay-cable surface will enhance the secondary spanwise vortex. Once the vortex induced vibration, the stay-cable vibration will be interfered by them, and then the vortex shedding is controlled and the lift fluctuation is suppressed.