Abstract The objective of this work is to study the effects of waves and ventilation on the dynamic hydroelastic response of a surface-piercing strut via towing tank studies. The experimental studies are especially designed to test the hypothesis that flow conditions affect the modal response and hence structural dynamics, which in turn affect the hydrodynamic response through fluid–structure interaction, particularly near regions of mode localization such as frequency coalescence. The results showed that the modal frequencies decrease with increasing submergence, and are higher in fully ventilated flow compared to fully wetted flow. Regular, non-breaking waves lead to simple harmonic oscillations about the mean values at the encountered wave frequency for the slowly varying component of the hydrodynamic loads and tip deformations. The spectral response of the fast fluctuating component of the hydrodynamic loads and tip deformations showed peaks at the modal frequencies and vortex shedding frequencies (off the blunt trailing edge of the strut). Significant dynamic load amplifications and flow-induced vibrations were observed when the second and third modal frequencies coalesced at a submerged aspect ratio of two in fully wetted flow. In fully ventilated flow, the second and third modes separated enough to result in drastically reduced dynamic load fluctuations and flow-induced vibrations. When the submergence decreased, the separation between the modal frequencies increased, which avoided frequency coalescence in both fully wetted and fully ventilated flows. The results suggest that for cases where the wave encountered frequency is well separated from the modal frequencies, the spectral response of the fast fluctuating component of the hydrodynamic loads and tip deformations are governed by the structural response, and not by wave conditions.

中文翻译：

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波浪和通风流中穿表面支柱的动态水弹性响应

摘要 这项工作的目的是通过拖船研究来研究波浪和通风对表面穿刺支柱的动态水弹性响应的影响。实验研究特别设计用于测试流动条件影响模态响应并因此影响结构动力学的假设，这反过来又通过流固耦合影响流体动力学响应，特别是在模式定位附近区域，例如频率合并。结果表明，模态频率随着淹没程度的增加而降低，并且与完全润湿的流相比，在完全通风的流中模态频率更高。对于水动力载荷和尖端变形的缓慢变化分量，规则的、非破碎的波导致关于所遇到的波频率的平均值的简谐振荡。流体动力载荷和尖端变形的快速波动分量的频谱响应在模态频率和涡旋脱落频率（远离支柱的钝后缘）处显示出峰值。当第二和第三模态频率在完全润湿流中以 2 的浸没纵横比合并时，观察到显着的动态载荷放大和流动引起的振动。在完全通风的流动中，第二和第三模式分离得足以导致动态负载波动和流动引起的振动显着减少。当淹没减少时，模态频率之间的间隔增加，这避免了完全润湿和完全通风流中的频率合并。结果表明，对于波遇到的频率与模态频率很好地分离的情况，