Subharmonic edge wave excitation by narrow-band, random incident waves

TitleSubharmonic edge wave excitation by narrow-band, random incident waves
Publication TypeJournal Article
Year of Publication2019
AuthorsVittori G., Blondeaux P., Coco G., Guza RT
Volume868
Date Published2019/06
Type of ArticleArticle
ISBN Number0022-1120
Accession NumberWOS:000465218300001
Keywordscoastal engineering; finite-amplitude; generation; mechanics; physics; surface gravity waves
Abstract

A monochromatic, small amplitude, normally incident standing wave on a sloping beach is unstable to perturbation by subharmonic (half the frequency) edge waves. At equilibrium, edge wave shoreline amplitudes can exceed incident wave amplitudes. Here, the effect of incident wave randomness on subharmonic edge wave excitation is explored following a weakly nonlinear stability analysis under the assumption of narrow-band incident random waves. Edge waves respond to variations in both incident wave phase and amplitude, and the edge wave amplitudes and incident wave groups vary on similar time scales. When bottom friction is included, intermittent subharmonic edge wave excitation is predicted due to the combination of bottom friction and wave phase. Edge wave amplitude can be near zero for long times, but for short periods reaches relatively large values, similar to amplitudes with monochromatic incident waves and no friction.

DOI10.1017/jfm.2019.214
Student Publication: 
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