The Formation of Edge Waves Under Monochromatic and Random Incident Waves
type: CreativeWork
description: Edge waves are coastal waves trapped near the shore by reflection and refraction. Previous studies show the excitation mechanism of edge waves under monochromatic wave conditions via phase locking and nonlinear growth. However, how efficiently the mechanism would work under random incident waves remains unclear. Consequently, this thesis aims: (1) to provide the first laboratory evidence of edge wave excitation under random incident waves and compare the edge wave growth under random incident waves with that under monochromatic incident waves; (2) to test the excitation mechanism proposed by a theory of edge wave excitation under narrow-banded random incident waves with laboratory measurements; and (3) to examine the performance of numerical models to reproduce the resonance between incident and edge waves. The laboratory experiments consist of cases in which edge wave excitation under monochromatic incident waves and cases in which edge waves are present under random incident waves. In the laboratory, edge waves develop when incident waves are monochromatic, and the edge wave amplitude remains unchanged when the waveform stabilises after the growth. By comparison, the presence of edge waves is intermittent when the incident wave energy is distributed over frequencies (i.e., with frequency spread) and directions (i.e., with directional spread). Edge waves modulate during the intermittent growth. Under incident waves with different levels of spread in frequencies and directions, modulating edge waves differ in amplitudes and durations. The observed intermittent edge wave growth agrees with predictions from the theoretical model. In the theoretical model, when narrow-banded, random incident waves are used, the predictions show that edge wave amplitudes keep modulating over time. Further comparisons based on decomposed incident waves and edge waves from the runup measured in the laboratory show the phase locking/unlocking between incident and edge waves consistent with…
abstract: Edge waves are coastal waves trapped near the shore by reflection and refraction. Previous studies show the excitation mechanism of edge waves under monochromatic wave conditions via phase locking and nonlinear growth. However, how efficiently the mechanism would work under random incident waves remains unclear. Consequently, this thesis aims: (1) to provide the first laboratory evidence of edge wave excitation under random incident waves and compare the edge wave growth under random incident waves with that under monochromatic incident waves; (2) to test the excitation mechanism proposed by a theory of edge wave excitation under narrow-banded random incident waves with laboratory measurements; and (3) to examine the performance of numerical models to reproduce the resonance between incident and edge waves. The laboratory experiments consist of cases in which edge wave excitation under monochromatic incident waves and cases in which edge waves are present under random incident waves. In the laboratory, edge waves develop when incident waves are monochromatic, and the edge wave amplitude remains unchanged when the waveform stabilises after the growth. By comparison, the presence of edge waves is intermittent when the incident wave energy is distributed over frequencies (i.e., with frequency spread) and directions (i.e., with directional spread). Edge waves modulate during the intermittent growth. Under incident waves with different levels of spread in frequencies and directions, modulating edge waves differ in amplitudes and durations. The observed intermittent edge wave growth agrees with predictions from the theoretical model. In the theoretical model, when narrow-banded, random incident waves are used, the predictions show that edge wave amplitudes keep modulating over time. Further comparisons based on decomposed incident waves and edge waves from the runup measured in the laboratory show the phase locking/unlocking between incident and edge waves consistent with…
author: Ding, Xuelin
license: https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm
date published: 2020
date modified: 2026-07-24T01:02:59Z
provider: University of Auckland
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: ResearchSpace@Auckland

PropertyValue
property ID: Handle
value: https://hdl.handle.net/2292/54599