倾斜布置柔性管的涡激振动特性实验研究

Experimental study on vortex-induced vibration of flexible pipe with yaw angles

该文采用高速摄像非介入测试方法,在循环实验水槽中开展了倾斜布置柔性管的涡激振动响应与IP(独立性)准则的适用性研究,通过分析振动频率、位移、斯特劳哈数及振动模态过渡特征,综合判断IP准则的适用范围。实验结果表明:倾角的增加引入了多频参与振动,且高频的权重不断增加,存在时间上的频率切换和空间上的频率竞争现象,流向模态过渡在较低的约化速度时出现;倾角的存在造成了平衡位置、振幅、频率及斯特劳哈数的变化,偏离了IP准则,因而对于柔性管而言,不能简单运用IP准则来预测其振动响应。

The vortex-induced vibration of an inclined flexible pipe is tested in a water flume using a nonintrusive measurement with high-speed cameras to evaluate the application of IP(independence)principle.The evaluation is performed by comprehensively considering the vibration frequency,response displacement,Strouhal number and response mode transition characteristics.The experimental results show that the existence of inclination angle introduces multi-frequency response,and the weights of higher modes increase with increasing of the inclination angle.The dominant frequency switches over time and varies along the pipe span.The appearance of the mode transition of in-line response shifts to a lower reduced velocity when there is anoblique angle.Furthermore,the existence of inclination angle leads to the alteration of equilibrium position,response amplitude,frequency and Strouhal number.Therefore,the IP principle cannot be simply used to predict the vibration response of flexible pipes.