Higher-order gap resonance between two identical fixed barges: a study on the effect of water depth
Higher-order gap resonance between two identical fixed barges: a study on the effect of water depth
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DOI：
10.1063/5.0089564
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发表时间：
2022-04
影响因子：
4.6
通讯作者：
Yunfeng Ding;J. Walther;Yanlin Shao
中科院分区：
文献类型：
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作者：
Yunfeng Ding;J. Walther;Yanlin Shao
使用二维 (2D) 全非线性数值波浪池 (NWT) 研究两个相邻的相同固定驳船形成的间隙中的非线性活塞模式流体共振。为了深入研究水深对间隙中高阶共振的影响，采用一致模型来描述有限水深和浅水深的入射波和波-结构相互作用。与之前的研究相反，在浅水波的作用下观察到强烈的四阶和五阶非线性间隙共振，从而产生与相应的一阶和二阶谐波相当的显着高次谐波响应。对于给定的波高，这些波比能够引起二阶或三阶间隙共振的有限深度波更为关键。在浅水波的作用下，在波槽处观察到高度振荡行为。这归因于高次谐波衍射效应，打破了入射波谐波之间的“完美抵消”，否则本应产生平滑且平坦的波谷。与线性衍射理论预测的不同，在长椭圆曲线下，间隙响应并不完全以准静态方式表现，并且高次谐波通常会与相应的入射波分量表现出更大的相位差，直到发生共振。本研究表明，在涉及活塞模式间隙响应的沿海环境中并行海上作业的设计和分析中，应始终考虑水深效应和高次谐波。
Nonlinear piston-mode fluid resonance in the gap formed by two identical fixed barges in close proximity is investigated using a two-dimensional (2D) fully nonlinear numerical wave tank (NWT). To delve into the effect of water depth on higher-order resonances in the gap, consistent models are employed to describe the incident waves and wave-structure interactions for finite and shallow water depths. In contrast to previous studies, strong 4th- and 5th-order nonlinear gap resonances are observed under the action of shallow-water waves, resulting in significant higher-harmonic responses that are comparable to the corresponding 1st and 2nd harmonics. For a given wave height, those waves are found to be more critical than the finite-depth waves which are capable of evoking 2nd- or 3rd-order gap resonance. Highly oscillatory behavior is observed at the trough under the action of shallow-water waves. This is ascribed to the higher-harmonic diffraction effects, breaking the `perfect cancellation' between the incident-wave harmonics which should otherwise produce smooth and flatter wave trough. Unlike what a linear diffraction theory will predict, the gap response does not behave completely in a quasi-static manner under long cnoidal waves, and the higher harmonics generally show larger phase differences to the corresponding incident-wave components until the resonance occurs. The present study suggests that the water-depth effect and higher harmonics should be consistently accounted for in the design and analysis of side-by-side marine operations in coastal environments involving piston-mode gap responses.