知识与财富的链接
利用作者编制的基于松耦合方法的求解气动弹性问题的程序,对圆柱和方柱等典型2维柱体的涡激振动进行了数值模拟.计算结果表明:2维柱体的涡激振动存在2个锁定状态,即低折减风速条件下的流向锁定和高折减风速条件下的横向锁定;随着折减风速的增大,2维柱体的旋涡脱落模式从异向2S(2 single)变化到同向2S;伴随着旋涡脱落模式的转变,气动力和位移之间的相位差出现0→π的剧烈变化,即相位转换现象;通过对相位转换现象进行分析,给出了涡激振动是限幅振动的机理解释.
By virtue of the code for the aeroelastic problems based on the loosely coupled method worked out by the authors,vortex-induced vibration (VIV) for typical cylinders,including circular and square cylinders are simulated. Computational results show that there exist two lock-in states for the VIV of the two dimensional cylinders:one is streamwise lock-in at lower reduced velocity and the other is lateral lock-in at higher reduced velocity.With the increase of the reduced velocity,the vortex shedding mode could be changed from out-of-phase 2S(2 single) to in-phase 2S,and at the same time,the phase difference between the aerodynamic force and the displacement could be changed from 0 to π,which is the so-called phase switch phenomenon.By analyzing the phase switch phenomenon,the mechanism for the limited amplitude of the VIV is studied.