考虑流固耦合的弹性圆柱体涡激振动研究

Vortex-induced vibration of an elastic cylinder considering fluid-structure interaction

利用CFX软件对质量比为7和3.24时圆柱体两向自由度涡激振动进行数值模拟,捕捉到了"锁定区"、"拍"和"相位开关"等现象,探讨了质量比对涡激振动的影响。最终通过研究表明:流固耦合在圆柱体涡激振动分析中应予以考虑;质量比为3.24时的锁定区范围、最大横向振幅以及达到锁定时的流速要比质量比为7时的大;质量比为7时顺流向频率一直为横向频率的2倍,但当质量比为3.24时,顺流向频率在较低约化速度(Ur≤4)下为横向频率的2倍,在较高约化速度下有两个值,一个为横向频率的2倍,另一个与横向频率接近。

The in-line and cross-flow vortex-induced vibration （VIV ）of a circular cylinder was simulated using CFX software,with the mass ratio of 7 and 3.24.The lock-in,beat and phase switch phenomena were caught and effects of mass ratio on VIV were discussed.The results show that fluid-structure interaction（FSI）should be considered in the analysis of VIV of cylinder.The range of lock-in,the maximum transverse amplitude and the velocity to achieve lock-in with the mass ratio of 3.24 are larger than those with the mass ratio of 7.The frequency of in-line VIV is always twice of that of cross-flow VIV when the mass ratio is 7.However,when the mass ratio is 3.24,the frequency of in-line VIV is twice of that of cross-flow VIV only at lower velocity reduction （Ur ≤4）.And there appear two frequencies at higher velocity reduction,the one is twice of frequency of cross-flow VIV,the other is close to that of cross-flow VIV.