Numerical simulation of vortex-induced vibration of a square cylinder at a low Reynolds number
Numerical simulation of vortex-induced vibration of a square cylinder at a low Reynolds number
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DOI：
10.1063/1.4792351
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发表时间：
2013-02
影响因子：
4.6
通讯作者：
Ming Zhao;Liang Cheng;T. Zhou
中科院分区：
文献类型：
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作者：
Ming Zhao;Liang Cheng;T. Zhou
通过有限元法求解Navier-Stokes方程，数值研究了雷诺数为100、低质量比为3时方柱的涡激振动（VIV）。通过求解方柱的运动方程来模拟振动，并采用Arbitrary Lagrangian Eulerian格式来模拟振动柱与流体之间的相互作用。数值模型的验证与发表的结果，通过一个固定的方柱和结果的涡激振动的圆柱在低雷诺数。研究了气流接近角α对方柱响应的影响。结果表明，α不仅影响振动的振幅，而且影响锁定区的大小。在所研究的三个α值（α = 0°、45°和22.5°）中，最小的振动幅度和最大的锁定区发生在α = 0°处。发现当α = 22.5°时，振动在两个约化速度区与固有频率锁定。在α = 22.5°和45°的锁定区观察到单圈振动轨迹，这与圆柱的涡激振动明显不同。结果，顺列方向上的振动频率与横流方向上的振动频率相同。
Vortex-induced vibrations (VIV) of a square cylinder at a Reynolds number of 100 and a low mass ratio of 3 are studied numerically by solving the Navier-Stokes equations using the finite element method. The equation of motion of the square cylinder is solved to simulate the vibration and the Arbitrary Lagrangian Eulerian scheme is employed to model the interaction between the vibrating cylinder and the fluid flow. The numerical model is validated against the published results of flow past a stationary square cylinder and the results of VIV of a circular cylinder at low Reynolds numbers. The effect of flow approaching angle (α) on the response of the square cylinder is investigated. It is found that α affects not only the vibration amplitude but also the lock-in regime. Among the three values of α (α = 0°, 45°, and 22.5°) that are studied, the smallest vibration amplitude and the narrowest lock-in regime occur at α = 0°. It is discovered that the vibration locks in with the natural frequency in two regimes of reduced velocity for α = 22.5°. Single loop vibration trajectories are observed in the lock-in regime at α = 22.5° and 45°, which is distinctively different from VIV of a circular cylinder. As a result, the vibration frequency in the in-line direction is the same as that in the cross-flow direction.