高雷诺数下圆柱顺流向和横向涡激振动分析

摘要

With CFD method,the characteristics of vortex-induced vibration for a circular cylinder under high Reynolds number were studied.Navier-Stokes equation and the circular cylinder's dynamic response equations were solved with the software FLUENT.With the dynamic mesh technique of FLUENT,single DOF and two-DOF fluid-structure interaction VIVs were simulated.Thus,lift coefficient,drag coefficient,amplitude ratio and vortex shedding frequency ratio versus Reynolds number were obtained.The lock-in and phase switch phenomena were caught.The results showed that in this Reynolds number range,the corresponding lockin region is for Ur =3 ～ 7.5.The results comparison of oneDOF and two-DOF VIV simulations showed that larger damping weakens VIV level,and in case of lower mass and small damping,longitudinal direction vortex-induced vibration aggravates transverse one.%利用CFD方法,研究了较高雷诺数下圆柱流向与横向耦合涡激振动特性.利用FLUENT软件求解粘性Navier-Stokes方程、圆柱涡激振动的结构动力响应方程,运用动网格技术,实现流固耦合,对圆柱进行了单自由度和两自由度涡激振动的数值模拟,得到了雷诺数为2.5×104 ～2.5×105范围内的圆柱涡激振动的升力系数、阻力系数、振幅比及频率比随约化速度变化的规律,捕捉到涡激流固耦合振动的“锁定”“相位开关”等现象,结果表明在此雷诺数范围内锁定区域对应的折减速度范围为Ur=3～7.5.对比单自由度及两自由度的模拟结果,表明在低质量比情况下,流向的振动会对横向振动产生影响.