Abstract Galloping is a critical type of flow-induced vibration (FIV) arising on power transmission lines, high rise buildings, pipe and cables bundles in the oil and gas industry. In this paper, we present a purely nonlinear energy sink (NES) that mitigates the galloping of a square prism. The NES is composed of a ball rotating freely in a circular track attached to the prism. The ball’s dynamics is coupled to that of the prism in a purely nonlinear way by inertia. We experimentally assess how this simple NES reduces the prism vibration by comparing the prism amplitude responses with and without the NES. A supplementary video presents these experiments, during which the NES ball exhibits different dynamics in three regimes; oscillatory, intermittent, and rotational. We characterize the ball behaviour and its effect on the prism response in each regime. The oscillatory regime appears at low flow speeds at which both the prism and the ball oscillate with small amplitude. The intermittent regime represents a transition mode within a small range of flow speeds and corresponds to a small jump in the vibration amplitude of the prism. The rotational regime appears at higher flow speeds, where the ball oscillates with relatively high angular speeds resulting in a strong modulated response of the prism. The design of the NES allows to easily vary its track dimensions to use a ball of different sizes and masses. Accordingly, we demonstrate the influence of the main NES parameters, which are the ball mass, NES track radius, ball friction, and radial clearance between NES track walls and the rotating ball, on both the prism response and the ball behaviour. The NES we present is directly amenable to mitigate other types of FIV.

中文翻译：

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具有纯非线性能量汇的疾驰减缓风洞演示

摘要 飞驰是石油和天然气行业输电线路、高层建筑、管道和电缆束中出现的一种临界类型的流动激振（FIV）。在本文中，我们提出了一种纯非线性能量汇 (NES)，可以减轻方形棱镜的飞驰。NES 由一个在连接到棱镜的圆形轨道中自由旋转的球组成。球的动力学通过惯性以纯非线性方式耦合到棱镜的动力学。我们通过比较有和没有 NES 的棱镜振幅响应，通过实验评估这个简单的 NES 如何减少棱镜振动。一个补充视频展示了这些实验，在此期间 NES 球在三种状态下表现出不同的动力学；振荡、间歇和旋转。我们描述了球行为及其对每个状态下棱镜响应的影响。振荡状态出现在低流速下，此时棱镜和球都以小幅度振荡。间歇状态代表小范围流速内的过渡模式，对应于棱镜振动幅度的小跳跃。旋转状态出现在较高的流速下，其中球以相对较高的角速度振荡，导致棱镜的强烈调制响应。NES 的设计允许轻松改变其轨道尺寸以使用不同尺寸和质量的球。因此，我们展示了主要 NES 参数的影响，即球质量、NES 轨道半径、球摩擦以及 NES 轨道壁与旋转球之间的径向间隙，关于棱镜响应和球行为。我们提出的 NES 可直接用于减轻其他类型的 FIV。