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| Registros recuperados: 26 | |
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| Mengual, Baptiste; Le Hir, Pierre; Cayocca, Florence; Garlan, T.. |
| Based on experiments, a trawling-induced erosion dynamics was included in a 3D realistic and pre-validated hydro-sedimentary model so as to assess its contribution to the overall regional sediment dynamics in the specific case of the Bay of Biscay continental shelf. The effect of trawling was investigated throughout a 5-year period in terms of horizontal/vertical fluxes and changes in seabed mud content, and compared to the natural variability of sediment fluxes at different spatio-temporal scales. Trawling is shown in the model to significantly contribute to sediment re-suspension, and changes in the seabed at the scale of the shelf. The contribution of trawling to re-suspension is >80% during the high fishing season at many locations on the outer... |
| Tipo: Text |
Palavras-chave: Sediment fluxes; Bottom trawling; Numerical modelling; Bay of Biscay; Continental shelf. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00500/61146/64574.pdf |
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| Kervella, Youen; Germain, Gregory; Gaurier, Benoit; Facq, Jean-valery; Cayocca, Florence; Lesueur, Patrick. |
| Oyster tables are artificial obstacles which are laid over muddy or sandy-muddy floors in intertidal areas. This study aims to show the current modifications related to the presence of the oyster table thanks to LDV measurement in a flume tank. Boundary layer development in different geometric configuration is underlined and suggests some important areas of velocity decrease and sediment transport modification. Shear stresses are also calculated near the bottom and around the table. The total shear stress in the water column exhibits an important increase when the flow passes through the oyster table, hence a flow energy decrease through dissipation. This study helps to understand the reasons for the increased sedimentation observed in some natural sites. |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00022/13359/10388.pdf |
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| Cayocca, Florence; Verney, Romaric; Petton, Sebastien; Caillaud, Matthieu; Dussauze, Morgan; Dumas, Franck; Le Roux, Jean-francois; Pineau-guillou, Lucia; Le Hir, Pierre. |
| The rising interest in environmental and ecosystem dynamics have lead coastal oceanographers to not only investigate the “traditional” physical parameters describing the ocean state and its dynamics (e.g. temperature, salinity, currents, water levels in coastal areas), but to also account for the dynamics of parameters describing its biogeochemical components. To that end, MARS3D regional and coastal modelling system has been coupled to ecosystem modules (ECO-MARS3D, ECO3M) as well as sediment dynamics modules (MARS3D-SEDIM): sediment, nutrient and primary production contents can be considered as the lower level environment and ecosystem descriptors of the “biogeochemical” ocean. Early investments into physical and biological analysis at the regional scale... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00194/30572/29015.pdf |
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| Le Hir, Pierre; Cayocca, Florence; Waeles, Benoit. |
| Mixed sediments are constituted of cohesive and non-cohesive materials with distinct behaviours that numerical models traditionally manage separately. This paper first introduces a rapid state of the Art in sediment transport modelling in order to point out the specific requirements for process-based models applied to mixed sediments. Based on a preliminary study by Waeles et al. (2007), which showed the validity of the advection approach to compute fine sand transport, a complete modelling strategy is described: it is applied to the suspended transport of sand and mud mixtures, and accounts for consolidation of mixed sediments. Special care is paid to the realistic representation of the structure and density of sand and mud mixtures, and to the... |
| Tipo: Text |
Palavras-chave: Sediment transport modelling; Mixed sediment; Sand; Mud; Suspension; Consolidation. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00028/13952/12567.pdf |
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| Sultan, Nabil; Cochonat, Pierre; Bourillet, Jean-francois; Cayocca, Florence. |
| This article presents a methodology developed to evaluate the instability of submarine slopes that extend over a large area. Special attention was paid to (1) the complex geometry (bathymetry) and the expanse of the slope, (2) the heterogeneity of the sediment, and (3) the distribution of the pore pressure. The safety factor was considered as a spatially varying quantity. The General Formulation (GLE, Fredlund and Krahn 1977), which fully satisfies equilibrium conditions, was used for evaluating the stability of the marine slope. The submarine slope failure, which occurred on 16 October 1979 during the construction of the new Nice airport, was studied in order to test the developed model. Geotechnical parameters were taken from experimental tests carried... |
| Tipo: Text |
Palavras-chave: Shear strength; Slope stability; Safety factor; Marine sediment; Finite element; Finite difference; Failure. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-698.pdf |
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| Kervella, Youen; Germain, Gregory; Gaurier, Benoit; Facq, Jean-valery; Cayocca, Florence; Lesueur, Patrick. |
| Oyster farming structures are artificial obstacles which disturb tidal flow and wave propagation. These effects can induce modifications of erosion and sedimentation patterns, turbidity changes, local silting up and can be threatening for the shellfish farming itself. The understanding of the impact of these structures in terms of hydrodynamics and sediment dynamics in the far-field, i.e. at the scale of a bay, is a very challenging task. In order to investigate the far-field impact, it is very important to understand in the first place all the changes which occur at a smaller scale, i.e. at the scale of a single table for a farm consisting of oyster tables made of metallic wire structures on which porous bags of oysters are laid. This work is carried out... |
| Tipo: Text |
Palavras-chave: Sediment dynamics; Roughness length; Boundary layer; Particle Image Velocimetry; Laser Doppler Velocimetry; Flume; Oyster table. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/2010/publication-7389.pdf |
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| Fossati, Monica; Cayocca, Florence; Piedra-cueva, Ismael. |
| This paper investigates the main characteristics of the fine sediments dynamics in a very complex and extensive inner shelf area located in South America, the Río de la Plata. The results derive from a 5 yr international research program that allowed intensive data acquisition throughout the area, as well as the development of the first numerical model investigating sediment dynamics at a regional scale in the area. The model is based on the MARS3D suite: it computes the regional tide- and wind-induced circulation, as well as sediment mixtures dynamics (erosion, advection and deposition of several sedimentary variables). Erosion due to wave action is taken into account thanks to the use of SWAN. The hydrodynamic and wave models were calibrated against... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00195/30577/29017.pdf |
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| Cugier, Philippe; Frangoudes, Katia; Blanchard, Michel; Mongruel, Remi; Perez, Jose; Le Mao, Patrick; Robin, T.; Fontenelle, Guy; Mazurie, Joseph; Cayocca, Florence; Pouvreau, Stephane; Olivier, F.. |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00026/13707/10862.pdf |
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| Batifoulier, Francois; Kervella, Youen; Laborde, Renaud; Cuny, Jérôme; Caillaud, Matthieu; Lazure, Pascal; Cayocca, Florence. |
| Les fortes vitesses rencontrées à l’entrée de la Baie du Mont Saint-Michel font de cet environnement macro-tidal un endroit privilégié, en termes de ressources énergétiques, pour l’implantation d’une ferme d’hydroliennes. Afin d’établir plus précisément son potentiel énergétique et d’évaluer l’impact de l’implantation de telles machines sur son hydrodynamisme, une modélisation hydrodynamique de la Baie du Mont Saint-Michel est mise en oeuvre à l’aide du modèle de circulation régionale MARS3D (LAZURE & DUMAS, 2008) dans sa version tridimensionnelle. La validation hydrodynamique de cette configuration est réalisée à partir de comparaisons à des mesures courantologiques récentes (KERVELLA, 2010). A partir de cette modélisation, une cartographie du... |
| Tipo: Text |
Palavras-chave: Modélisation régionale; Hydroliennes; Baie du Mont Saint-Michel; Hydrodynamisme; Potentiel énergétique. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00195/30599/29055.pdf |
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| Mengual, Baptiste; Cayocca, Florence; Le Hir, Pierre; Draye, Robin; Laffargue, Pascal; Vincent, Benoit; Garlan, Thierry. |
| Sea trials were performed on two zones with different fishing efforts on the continental shelf of the Bay of Biscay ('Grande-VasiSre' area of muddy sand) in order to assess particulate matter resuspension and seabed disturbances (i.e., penetration, reworking, grain size changes) induced by different types of trawls. Optical and acoustic measurements made in the water column indicate a significant trawling-induced resuspension mainly due to the scraping action of doors. It manifests as a highly dynamic turbid plume confined near the seabed, where suspended sediment concentrations can reach 200 mg l(-1). Concentration levels measured behind an "alternative" configuration (trawls with jumper doors instead of classical doors penetrating the sediment) are... |
| Tipo: Text |
Palavras-chave: Bottom trawling; Sedimentresuspension; Seabed disturbance; Erosion flux; Bay of Biscay. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00353/46428/51396.pdf |
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| Mengual, Baptiste; Le Hir, Pierre; Cayocca, Florence; Garlan, Thierry. |
| This study describes the building of a common erosion law for fine sand and mud, mixed or not, in the case of a typical continental shelf environment, the Bay of Biscay shelf, characterized by slightly energetic conditions and a seabed mainly composed of fine sand and muddy sediments. A 3D realistic hydro-sedimentary model was used to assess the influence of the erosion law setting on sediment dynamics (turbidity, seabed evolution). A pure sand erosion law was applied when the mud fraction in the surficial sediment was lower than a first critical value, and a pure mud erosion law above a second critical value. Both sand and mud erosion laws are formulated similarly, with different parameters (erodibility parameter, critical shear stress and power of the... |
| Tipo: Text |
Palavras-chave: Sand-mud mixture erosion; Numerical modelling; Non-cohesive to cohesive transition. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00394/50588/51280.pdf |
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| Registros recuperados: 26 | |
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