马蹄波波形特征和对圆柱作用实验研究

为了研究真实海洋表面马蹄波特性以及对建筑物的作用,通过物理模型实验研究了马蹄波的波形特征参数以及马蹄波对圆柱体的作用。实验中通过对浪高仪采集的波面升高时间历程曲线进行分析得出了不同水深情况下马蹄波的垂向几何特征,并通过快速傅里叶变换得出了马蹄波波幅谱的特征,研究了马蹄波各组成波波幅沿空间的变化从而得出了圆柱存在对马蹄波演化的影响,同时给出马蹄波绕射形成的波面分布和不同频率谐波在圆柱周围的分布,讨论了马蹄波不同于Stokes波对圆柱作用的特征。结果表明,马蹄波波形受水深影响较大,水深越浅,马蹄波的波面形状越接近椭圆余弦波。圆柱体的存在干扰了马蹄波不稳定的增长,使其在接近圆柱时呈下降趋势,导致不稳定幅值最大值的位置提前并且出现在偏离圆柱迎浪点的侧表面,从而使圆柱受到侧向力的作用。

Experimental study of waveform features of crescent wave and interaction with cylinder

In order to study the features of crescent waves occurring on the sea and their interaction with offshore structures, physical model experiments are carried out to study the characteristics of crescent waves and their interaction with cylinder. In the experiment, the vertical geometrical features of crescent wave with different water depths are obtained by analyzing the time series of surface elevation collected by the wave gauges. The characteristics of the crescent wave amplitude spectrum are obtained by fast Fourier transform. The influence of the existence of the cylinder on the evolution of the crescent wave is also studied. At the same time, the wavefront distribution formed by the crescent wave diffraction and the distribution of the harmonics of different frequencies around the cylinder are discussed. The characteristics of the crescent wave, different from the Stokes wave, are discussed. The results show that the crescent wave is affected by the water depth: the deeper the water depth, the closer the wave surface shape is to the elliptical cosine wave. The presence of the cylinder interferes with the unstable growth of the crescent wave, which tends to descend near the cylinder, leading to the position of the maximum value of the unstable amplitude in advance and appearing on the side surface deviating from the cylinder point, so that the cylinder is affected by the lateral force.