Tower-like structures with circular section are prone to unexpected across-wind vortex-induced vibration (VIV), and the along-wind response is usually neglected due to its amplitude being much smaller than that of VIV. Recent research pertaining to tall buildings has revealed, nevertheless, that the structural responses in the along-wind and across-wind directions are coupled in a way that results in a decrease in the across-wind response at the wind speed of VIV along with an increased along-wind response. However, the impact of coupling on tower-like structures has not yet been examined. Moreover, tower-like structures with a circular cross section undergo tip-induced vibration at the wind speed higher than vortex-resonance wind speed. However, the impact of this coupling effect on the tip-induced vibration remains uncertain. In this paper, a two-degree-of-freedom rocking model wind tunnel test is carried out under low turbulence and turbulent flow to investigate the coupling effect of tower-like structures. Experiment results show that the coupling effect exists at both the vortex-resonance vibration wind speed and the tip-induced vibration wind speed. Besides, when the along-wind response is coupled with the across-wind responses, it illustrates a steady harmonic vibration with a hardened non-Gaussian characteristic, and its kurtosis decreases to 1.5. Finally, the measured tip-associated vortex shedding frequency suggests that there is a “lock-in” phenomenon of the tip-induced vibration, this new finding improves the understanding of the wind-induced response at high wind speeds.

中文翻译：

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考虑顺风向和横风向耦合效应的圆柱体涡激振动实验研究

圆形截面的塔状结构容易产生意外的横风涡激振动（VIV），而顺风响应由于其振幅远小于VIV，因此通常被忽略。然而，最近有关高层建筑的研究表明，顺风向和横风向的结构响应以某种方式耦合，导致 VIV 风速下的横风响应下降，并且增加顺风响应。然而，耦合对塔状结构的影响尚未得到研究。此外，具有圆形横截面的塔状结构在高于涡共振风速的风速下会经历尖端引起的振动。然而，这种耦合效应对尖端引起的振动的影响仍然不确定。本文通过低湍流和湍流条件下的二自由度摇摆模型风洞试验，研究塔状结构的耦合效应。实验结果表明，涡共振风速和尖端激振风速均存在耦合效应。此外，当顺风向响应与横风向响应耦合时，呈现出具有硬化非高斯特性的稳态简谐振动，其峰度降至1.5。最后，测量的尖端相关涡旋脱落频率表明存在尖端引起的振动的“锁定”现象，这一新发现提高了对高风速下风致响应的理解。