| Autor: |
Marchesiello, Patrick, Chauchat, Julien, Shafiei, Hassan, Almar, Rafael, Benshila, Rachid, Dumas, Franck |
| Přispěvatelé: |
Institut de Recherche pour le Développement (IRD), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense |
| Jazyk: |
angličtina |
| Rok vydání: |
2021 |
| Předmět: |
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| Popis: |
The problem of sandbar migration on the storm timescale is revisited with a 3D waveresolving hydro-sedimentary model. The model accurately simulates the successive offshore and onshore bar migration observed in a large-scale flume experiment (LIP11D) in response to wave forcing representing storm and post-storm (recovery) conditions. The diagnosis of sand transport and the analysis of a composite asymmetric wave cycle reveal the migration mechanisms in each phase. In all cases, sediment resuspension is dominated by breakinginduced turbulence, while net sediment transport and bed profile evolution are primarily the result of undertow distribution across the sandbar, rather than a trade-off between onshore and offshore fluxes. In the erosion phase, a strong undertow carries the mobilized sediment seaward of the bar crest. In the accretion phase, the sandbar becomes the breaking point to more moderate waves and the undertow is limited to the lee-side of the bar, causing an counterflow migration of the bar crest. The contribution of wave-related onshore fluxes is significant in this case-although secondary in magnitude-and coincide with higher mobilization and currents during the wave crest period. We conclude that computationally efficient 3D wave-resolving models (including morphological acceleration) can be used to improve our understanding of nearshore morphodynamic problems in realistic applications. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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