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Experimental study of wave trains generated by vertical bed movements
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Jose Horrillo-Caraballo,
Harshinie Karunarathna ,
Xin Wang Wang
Applied Ocean Research, Volume: 147
Swansea University Authors:
Dominic Reeve , Jose Horrillo-Caraballo, Harshinie Karunarathna , Xin Wang Wang
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© 2024 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license.
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DOI (Published version): 10.1016/j.apor.2024.103971
Abstract
Laboratory experiments were conducted to explore the wave trains generated by vertical bed movements. The investigation consisted of 32 cases, involving four different water depths with unimodal and bimodal bed movements. Water surface displacement was measured using gauges positioned along a 30m lo...
| Published in: | Applied Ocean Research |
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| ISSN: | 0141-1187 |
| Published: |
Elsevier BV
2024
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| Online Access: |
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa65906 |
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| Abstract: |
Laboratory experiments were conducted to explore the wave trains generated by vertical bed movements. The investigation consisted of 32 cases, involving four different water depths with unimodal and bimodal bed movements. Water surface displacement was measured using gauges positioned along a 30m long tank. A PIV system was set up to provide detailed measurement of the fluid velocity field in the vicinity of the bed movement. Generally, a unimodal movement generated a solitary-like wave, followed by a trailing sequence of waves. A bimodal bed movement induced a more complex flow field, with both the first and second extrema being significant. New analytical solutions have been derived, enabling the calculation of velocity fields. The nature of the wave generation and propagation were characterised using the disturbance-amplitude scale (α) and disturbance-size scale (δ). The applicability of linear theory was investigated, by validating the linear solutions of the generated waves against the experimental observations. For α ≤ 0.25, the analytical solutions were in good agreement with observations of the free surface shape, flow field and wave elevation history. For α ≥ 0.5, non-linearity became more pronounced, and the analytical solutions were only capable of reasonably estimating the amplitude of the first extremum in the vicinity of the moving bed. The initial crest maintained its amplitude and shape more effectively in crest-leading waves, whereas the leading trough decayed significantly in trough-leading waves. Non-linear phenomena were observed, such as wave breaking, air entrapment and twisted free surface. Bimodal bed movements with α ≥ 0.5 generated large, steep crests immediately following the initial trough in trough-leading waves. |
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| Keywords: |
Laboratory experiment; Wave generation; Vertical bed movement; Non-linearity |
| College: |
Faculty of Science and Engineering |
| Funders: |
This work is supported by European Regional Development Fund through the Welsh Government via the SEACAMS2 project. |