Higher-harmonic contributions to surface elevation, kinematics, and wave loads in wave packets across an abrupt depth transition

IF 4.2 2区工程技术 Q1 ENGINEERING, CIVIL

Coastal Engineering Pub Date : 2025-01-02 DOI:10.1016/j.coastaleng.2024.104693

Charlotte S. Moss , David M. Schultz , Ben Parkes , Yan Li , Samuel Draycott

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引用次数: 0

Abstract

The evolution of narrow-banded wave packets across an abrupt depth transition is examined using both laboratory experiments and a fully nonlinear potential-flow model. Whereas available theoretical studies focus up to the second harmonic, here we focus on higher harmonics (i.e., third–fifth) leading to nonlinearity and thereby amplified wave steepness, wave kinematics, and wave force. Surface elevations obtained from laboratory experiments are used to verify the model, with good agreement up to and including the fifth harmonic. Horizontal velocity and acceleration from the model simulations are used to calculate the horizontal force on a cylinder using the Morison equation. The first to fifth harmonics are extracted from the profiles of wave characteristics (e.g., surface elevations, kinematics, wave force) using a Fast Fourier Transform-based bandpass filter to assess their contributions. Higher harmonics accounted for up to 25% of the total surface elevation, up to 30% of horizontal acceleration, and up to 33% in wave force. Thus, higher harmonics should be accounted for in the evolution of waves in coastal waters to ensure loads are not under-estimated.

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高次谐波对地表高程、运动学和波浪载荷的贡献

利用实验室实验和完全非线性势流模型研究了窄带波包在深度突变中的演化。虽然现有的理论研究集中在二次谐波，但在这里，我们关注的是导致非线性的更高次谐波（即三次五次谐波），从而放大了波的陡度、波的运动学和波的力。从实验室实验中获得的地表高程用于验证模型，该模型在五次谐波范围内具有良好的一致性。利用模型模拟得到的水平速度和加速度，用莫里森方程计算圆柱上的水平力。使用基于快速傅立叶变换的带通滤波器从波特征（例如，表面高度，运动学，波浪力）的剖面中提取第一到第五次谐波来评估它们的贡献。高次谐波占地表总高程的25%，占水平加速度的30%，占波浪力的33%。因此，在沿海水域波浪的演变中应考虑高次谐波，以确保荷载不会被低估。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Coastal Engineering 工程技术-工程：大洋

CiteScore

9.20

自引率

13.60%

发文量

审稿时长

3.5 months

期刊介绍： Coastal Engineering is an international medium for coastal engineers and scientists. Combining practical applications with modern technological and scientific approaches, such as mathematical and numerical modelling, laboratory and field observations and experiments, it publishes fundamental studies as well as case studies on the following aspects of coastal, harbour and offshore engineering: waves, currents and sediment transport; coastal, estuarine and offshore morphology; technical and functional design of coastal and harbour structures; morphological and environmental impact of coastal, harbour and offshore structures.