Individual violent wave-overtopping events: behaviour and estimation
To better understand individual violent wave overtopping, of significance for coastal defence design, three breaking wave types (steep-fronted, plunging and broken) based on focused wave groups, were generated in laboratory and numerical models. High-speed video captured overtopping events and produ...
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Published in | Journal of hydraulic research Vol. 58; no. 1; pp. 34 - 46 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Madrid
Taylor & Francis
02.01.2020
Taylor & Francis Ltd |
Subjects | |
Online Access | Get full text |
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Summary: | To better understand individual violent wave overtopping, of significance for coastal defence design, three breaking wave types (steep-fronted, plunging and broken) based on focused wave groups, were generated in laboratory and numerical models. High-speed video captured overtopping events and produced velocity vector maps by means of bubble image velocimetry (BIV). Results were compared with a numerical model based on a linear wave detection procedure and a two-phase incompressible Navier-Stokes-based solver. This novel approach revealed that the overtopping waves comprised an initial jet of 0.2 s duration, but dominated by quasi-steady flow. Whilst laboratory surface-elevation time-histories were highly repeatable, overtopping volume repeats were sensitive to the breaker type. Measured volumes were compared with: the numerical model (which over-predicted, but was reasonably accurate for steep-fronted waves); estimations based on BIV results (which provided very close agreement for the steep-fronted waves); and a weir-based analogy (which provided reasonable agreement, but always under-predicted). |
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ISSN: | 0022-1686 1814-2079 |
DOI: | 10.1080/00221686.2018.1555549 |