Consulta: subjectFacets:"Hydrodynamic"
Registros recuperados: 22
Data/hora: 01/06/2024 09:21:29

Etude numérique du train de pêche d'un chalutier (DEA)
Provedor de dados: 5
Autores: Theret, Francois.
IFREMER aims at digitalizing trawl gear in order to reach two goals: on the one hand, participating in the realisation of a computer assisted trawl conception software; on the other hand, being able to study quickly and easily the influence of different adjustment parameters on the shape of the trawl in order to indicate to the skipper, if possible in real time, the optimal adjustment for the conditions he's in. From an international point of view, there are only two strategies to approach this problem: - the first strategy is based on statistical studies on the existing nets (almost limited to their reproduction on different scales), but this approach does not leave much room for innovation as it can only be applied to the same type of nets as those that...
Tipo: Text
Palavras-chave: Experimentation; Optimization; Adjustment; Hydrodynamic; Modelization; Trawl gear; Trawl; Expérimentation; Maquette de chalut; Optimisation; Réglage; Hydrodynamique; Modèle numérique; Train de pêche; Chalut.
Ano: 1990
URL: http://archimer.ifremer.fr/doc/1990/these-3627.pdf

Étude par télédétection de la dispersion en mer des eaux estuariennes issues de la Gironde et du Pertuis de Maumusson
Provedor de dados: 5
Autores: Castaing, P; Allen, Gp; Houdart, Michel; Moign, Y.
The objective of this study, carried out in the Gironde estuary inlet, was to determine the nature of the seaward dispersion of estuarine water and suspended sediments during a spring tide and high river flow. On June 3, 19(7, three flights were made over the inlet, at mid ebb, low tide and mid flood. The planned flight at high tide was cancelled due to adverse meteorological conditions. During each flight, thermal infrared coverage was obtained, together with black and white photographs. These data were correlated with concomitant ground mesures of current velocity, salinity, temperature and suspended sediment concentration Four types of water masses were identified during the tidal cycle: estuarine "very warm and turbid" water; estuarine "cooler and...
Tipo: Text
Palavras-chave: Hydrodynamique; Suspensions; Télédétection; Eaux côtières; Estuaire; Gironde; Hydrodynamic; Suspended sediments; Remote sensing; Coastal waters; Estuary; Gironde.
Ano: 1979
URL: http://archimer.ifremer.fr/doc/00122/23361/21188.pdf

Influence of environmental and anthropogenic factors on the composition, concentration and spatial distribution of microplastics: A case study of the Bay of Brest (Brittany, France)
Provedor de dados: 5
Autores: Frere, L.; Paul-pont, I.; Rinnert, Emmanuel; Petton, Sebastien; Jaffre, J; Bihannic, Isabelle; Soudant, P.; Lambert, C.; Huvet, Arnaud.
The concentration and spatial distribution of microplastics in the Bay of Brest (Brittany, France) was investigated in two surveys. Surface water and sediment were sampled at nine locations in areas characterized by contrasting anthropic pressures, riverine influences or water mixing. Microplastics were categorized by their polymer type and size class. Microplastic contamination in surface water and sediment was dominated by polyethylene fragments (PE, 53–67%) followed by polypropylene (PP, 16–30%) and polystyrene (PS, 16–17%) microparticles. The presence of buoyant microplastics (PE, PP and PS) in sediment suggests the existence of physical and/or biological processes leading to vertical transfer of lightweight microplastics in the bay. In sediment (upper...
Tipo: Text
Palavras-chave: Microplastic; Coastal ecosystem; Surface water; Sediment; Raman spectroscopy; Hydrodynamic; Dispersal particle modelling.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00379/48994/51083.pdf

Modélisation du devenir à moyen terme dans l'eau et le sédiment des éléments majeurs (N, P, Si) rejetés par la Seine en Baie de Seine
Provedor de dados: 5
Autores: Cugier, Philippe.
The Bay of Seine is a coastal ecosystem submitted to a large river input (Seine river), which brings important quantities of nutrients. This nutrient enrichment leads to frequent eutrophication events and, from the beginning of the eighties, regular toxic phytoplanktonic (Dynophysis) blooms are observed.  In order to study the nutrient cycles (nitrogen, phosphorus, silica) and their contribution to phytoplanktonic stock regulation, a three dimensional model has been developed, based on the coupling between an hydrodynamic part taking into account sediment dynamics (SAM-3D) and an ecological part, which accounts for the main biological compartments and processes.  This model is able to reproduce the main physical and biological characteristics of the...
Tipo: Text
Palavras-chave: Bay of Seine (France); Dinoflagellates; Nutrients; Nutrients; Eutrophication; Sediments; Hydrodynamic; Mathematical models; Baie de (France); Seine; Dinoflagellés; Diatomées; Nutriments; Eutrophisation; Sédiments (géologie); Hydrodynamique; Modèles mathématiques.
Ano: 1999
URL: http://archimer.ifremer.fr/doc/1999/these-3220.pdf

Etude sédimentaire de la baie de Quiberon : la zone ostréicole en eau profonde et ses abords
Provedor de dados: 5
Autores: Lemoine, Gérard.
Tipo: Text
Palavras-chave: Hydrobiology; Hydrodynamic; Sedimentology; Oyster culture zone.
Ano: 1989
URL: http://archimer.ifremer.fr/doc/1989/rapport-2210.pdf

Study of the manoeuvrability and security of a trawl gear
Provedor de dados: 5
Autores: Marichal, Dominique; Vincent, Benoit.
A complete method is presented for determining the static and dynamic behaviour of a fishing gear. The net, which is very flexible, is modelised by a set of rigid bars. The hydrodynamic forces, applied to each bar, are determined by combining and generalizing the Landweber and Morison hypothesis. A CFD method is used to calculate the forces on trawl doors. The fundamental principle of dynamics is completed with length equations expressing the elasticity of the bars. It leads to a set of second order non-linear differential equations, which is solved using a Runge-Kutta method. We will now present a few examples of the various applications of our works : the study of the trawl gear equilibrium in a uniform flow, an example of manoeuvrability (gyration of...
Tipo: Text
Palavras-chave: Runge Kutta; Elasticity; Simulation; Model; Trawl doors; Hydrodynamic; Fishing gear; Runge Kutta; Elasticite; Simulation; Modèle; Panneaux de chalut; Hydrodynamique; Engin de pêche.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/acte-4612.pdf

Numerical simulation of the wake of marine current turbines with a particle method
Provedor de dados: 5
Autores: Pinon, Gregory; Mycek, Paul; Germain, Gregory; Rivoalen, Elie.
This paper presents numerical computations of three bladed horizontal axis marine current turbines in a uniform free upstream current. The unsteady evolution of the turbine wake is taken into account by some three-dimensional software, developed to assess the disturbances generated in the sea. An unsteady Lagrangian method is considered for these computations using "Vortex Method": a velocity-vorticity numerical implementation of the Navier-Stokes equations. The vortex flow is discretised with particles carrying vorticity, which are advected in a Lagrangian frame. The present paper aims at presenting results on both power and thrust coefficient (C-p and C-T) predictions and wake characterisation, up to ten diameters downstream of the turbine. Moreover, two...
Tipo: Text
Palavras-chave: Numerical computations; Marine current turbine; Hydrodynamic; Power and thrust coefficients; Wake.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00087/19853/17616.pdf

Modélisation du transport particulaire dans le Golfe du Lion en vue d'une application au devenir des traceurs radioactifs issus du Rhône
Provedor de dados: 5
Autores: Dufois, Francois.
Among the contaminants introduced into the environment, the artificial radionuclides appear particularly important to take into account because of their chemical toxicity and/or of their radiotoxicity. Some radionuclides present a high affinity with particles so that the study of the sediment dynamics is a useful preliminary to the study of their dispersion on the open sea. This thesis is focused on the fate of sediments in the Gulf of Lions (NW Mediterranean) and in particular on the impact of the Rhone River, which is the main source of particulate matter in the Gulf of Lions. In order to study the sediment transport mechanisms on various space and time scales, this thesis is based on mathematical modelling. The hydro-sedimentary model set up in the Gulf...
Tipo: Text
Palavras-chave: Waves; MARS 3D; Hydrodynamic; Radionuclides; Modelling; Sediment; Rhône prodelta; Gulf of Lions; Vagues; MARS 3D; Hydrodynamique; Radioéléments; Modélisation; Sédiment; Prodelta du Rhône; Golfe du Lion.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/these-6308.pdf

Modelling of circulation and dispersion of radioactive pollutants in the Japan Sea
Provedor de dados: 5
Autores: Cetina, Matjaz; Rajar, Rudi; Povinec, Pavel.
A large amount of radioactive waste was deposited in the Japan Sea, at a depth of about 3 000 m by the former Soviet Union. Research was carried out to determine to what extent the surface waters could be contaminated by possible leakage from the dumped containers. A three-dimensional, non-linear, baroclinic model was used to determine the circulation and pollutant dispersion. The computations were carried out in the diagnostic mode, taking into account data on winter and summer temperature and salinity distribution. Thermohaline forcing due to strong temperatures and salinity gradients is the main forcing factor influencing the bottom circulation. Wind forcing and the inflow/outflow surface currents were also taken into account. The simulated velocity...
Tipo: Text
Palavras-chave: Hydrodynamique; Modélisation 3D; Pollution radioactive; Mer du Japon; Hydrodynamic; 3D modelling; Radioactive pollution; Japan Sea.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/00323/43378/42833.pdf

Rapport 2018 Ifremer. Evolution des lagunes de Saint Pierre et Miquelon. Dynamique de renouvellement des masses d’eaux du Grand Barachois
Provedor de dados: 5
Autores: Le Moine, Olivier; Geairon, Philippe; Robert, Stephane; Coudray, Sylvain; Fiandrino, Annie; Goraguer, Herle; Goulletquer, Philippe.
La dynamique des masses d'eaux et les flux de transit semble favoriser un comblement et/ou des limitations de renouvellement d'eau mettant en péril la durabilité de l’environnement de cette lagune Miquelonnaise. La Préfecture de Saint Pierre et Miquelon et la DTAM, en soutien à la gestion durable de cet environnement, ont sollicité l’Ifremer pour l’évaluation des flux d’alimentation de cette lagune. Une mission sur place a été réalisée en juin 2016 afin de coordonner les actions et effectuer les mesures préliminaires portant sur les jaugeages, la bathymétrie du chenal et la courantométrie horizontale. Ces données ont ensuite été complétées par une acquisition continue des vitesses de courant, avec des données disponibles du 2 juin au 15 novembre 2016, puis...
Tipo: Text
Palavras-chave: Hydrodynamique; Renouvellements; Saint Pierre et Miquelon; Lagune; Grand Barachois; Hydrodynamic; Renewal rates; Saint Pierre et Miquelon; Lagoon; Grand Barachois.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00478/58974/61587.pdf

Caractérisation des composantes hydrodynamiques d'une lagune mésotidale, le Bassin d'Arcachon.
Provedor de dados: 5
Autores: Plus, Martin; Maurer, Daniele; Stanisiere, Jean-yves; Dumas, Franck.
Introduction and objectives of the study: Understanding the operation modes of the coastline systems requires the study of the hydrodynamics responsible for transporting the whole of the chemical and biological elements of which they are composed. The idea of maintaining a close connexion between the physics, biology, geology and chemistry of the oceans is not new, and was for that matter the subject of a note in the first report of the International Council for the Study of the Oceans (ICSS) in 1902 (Sverdrup et al., 1954):  " it was seen from the beginning that the study of the physical conditions, of the chemical nature of the ocean waters, of the currents, etc., was of the greatest importance for the investigation of the problems connected with life,...
Tipo: Text
Palavras-chave: France; Atlantic north east; Arcachon basin; Modelling; Measuring; Current; Hydrodynamic.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/rapport-2352.pdf

Small-scale variability of the current in the Strait of Bonifacio
Provedor de dados: 5
Autores: Gerigny, Olivia; Coudray, Sylvain; Lapucci, Chiara; Tomasino, Corinne; Bisgambiglia, Paul-antoine; Galgani, Francois.
Current dynamics in the Strait of Bonifacio (south Corsica) were investigated at a small scale during the STELLAMARE1 multidisciplinary cruise in summer 2012, using in situ measurements and modeling data. The Strait of Bonifacio is a particularly sensitive marine area in which specific conservation measures have been taken to preserve the natural environment and wild species. Good knowledge of the hydrodynamics in this area is essential to optimize the Marine Protected Area's management rules. Therefore, we used a high-resolution model (400 m) based on the MARS3D code to investigate the main flux exchanges and to formulate certain hypotheses about the formation of possible eddy structures. The aim of the present paper is first to synthetize the results...
Tipo: Text
Palavras-chave: ADCP profiles; Regional model; Hydrodynamic; Corsica current; Strait circulation; North-west Mediterranean basin.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00275/38631/39755.pdf

Etude du fonctionnement hydrosédimentaire d'un écosystème lagunaire sur des échelles de temps multiples. Application au complexe lagunaire "étangs Palavasiens - étang de l'Or - canal du Rhône à Sète"
Provedor de dados: 5
Autores: Castaings, Jerome.
The sedimentary evolution of coastal lagoons is a complex phenomenon involving both short term extreme processes (floods, storms) and long term processes (mean sea level variations, climate change). If general mechanisms of these phenomena are well known, their spatial and temporal variability makes them difficult to assess at the local scale. The diversity of lagoonal environments and human influence makes this even more risky. I have focussed this study on the case of a Mediterranean lagoon system : “Palavasian lagoons, Or lagoon, and Rhône-Sète waterway” which is located in the Gulf of Lion (South of France). A ultidisciplinary approach was used to assess sediment dynamics on multiple time scales. An average filling rate of 1.3 mm.year-1 over the two...
Tipo: Text
Palavras-chave: Dynamique sédimentaire; Géochronologie; Hydrodynamique; Échelles temporelles; Lagunes; Sediment dynamic; Geochronology; Hydrodynamic; Time scales; Lagoons.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00193/30436/28853.pdf

Modelisation morphodynamique de l'embouchure de la seine
Provedor de dados: 5
Autores: Waeles, Benoit.
The mouth of the Seine has been undergoing intense morphological changes for decades, because of containment work to improve access to the ports of Rouen and Le Havre. A significant trend is the progradation of the downstream estuary. Simultaneously, the surface area of the intertidal mudflats tends to decrease. The estuary's sediments are composed of silt and fine sand (respectively transported from the river Seine and the open sea). Their distribution is linked to the hydrodynamic characteristics of the estuary and may display layered vertical structures. To understand the estuary's morphological changes, a morphodynamic ditigal model is developed from a validated (3D) model of silty sediment transport. A model of suspended fine sand transport as well as...
Tipo: Text
Palavras-chave: Seine estuary; Modelling; Sediment transport; Hydrodynamic; Morphodynamic; Seine estuaire; Modelisation; Transport sediment; Hydrodynamique; Morphodynamique.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/these-2195.pdf

Caractérisation des composantes hydrodynamiques d'un système côtier semi-fermé : Le Bassin de Marennes-Oléron
Provedor de dados: 5
Autores: Stanisiere, Jean-yves; Dumas, Franck; Plus, Martin; Maurer, Daniele; Robert, Stephane.
Introduction and objectives of the study: Understanding the operating modes of the coastline systems requires the study of the hydrodynamics responsible for transporting the whole of the geobiological compartments of which they are composed. The idea of maintaining a close connexion between the physics, biology, geology and chemistry of the oceans is not new, and was for that matter the subject of a note in the first report of the International Council for the Study of the Oceans (ICSS) in 1902 (Sverdrup et al., 1954): ... it was seen from the beginning that the study of the physical conditions, of the chemical nature of the ocean waters, of the currents, etc., was of the greatest importance for the investigation of the problems connected with life, that...
Tipo: Text
Palavras-chave: France; Atlantic north east; Marennes Oleron basin; Modellling; Hydrodynamic.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/rapport-2353.pdf

Towed Gear Optimisation, application to trawls
Provedor de dados: 5
Autores: Roullot, Jean; Vincent, Benoit.
IFREMER has been developing and commercialising scientific software to help the conception and optimisation of any kind of trawl. This software named DynamiT makes available a "virtual flume tank" where tests can be achieved without any constraint due to scale effects or other limitation when physically testing out. DynamiT has been used numbers of times to simulate and optimise trawls by different net makers and by IFREMER. The software is based on the resolution of the mechanics (structure and hydrodynamic) equations of a model describing the actual trawl and its rigging. The "user friendly" interface allows the user to iterate "modification and observations" cycles to reach an optimised state of the fishing gear. The process can be used to reduce the...
Tipo: Text
Palavras-chave: Hydrodynamic; Fuel consumption; Simulation; Model; DynamiT; Software; Fishing; Hydrodynamique; Consommation de carburant; Simulation; Modèle; DynamiT; Logiciel; Pêche.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/acte-4613.pdf

Flume tank characterization of marine current turbine blade behaviour under current and wave loading
Provedor de dados: 5
Autores: Gaurier, Benoit; Davies, Peter; Deuff, Albert; Germain, Gregory.
The long term reliability of tidal turbines is critical if these structures are to be cost-effective. Optimized design requires a combination of material durability models and structural analyses which must be based on realistic loading conditions. This paper presents results from a series of flume tank measurements on strain gauged scaled turbine blades, aimed at studying these conditions. A detailed series of tests on a 3-blade horizontal axis turbine with 400 mm long blades is presented. The influence of both current and wave-current interactions on measured strains is studied. These tests show that wave-current interactions can cause large additional loading amplitudes compared to currents alone, which must be considered in the fatigue analysis of...
Tipo: Text
Palavras-chave: Experimental trials; Wave and current effects; Marine current turbine; Blade deformations; Hydrodynamic.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00136/24693/22770.pdf

Projet lagune du Grand Barachois : Rapport Phase 1
Provedor de dados: 5
Autores: Le Moine, Olivier; Robert, Stephane; Geairon, Philippe; Goraguer, Herle; Goulletquer, Philippe.
La dynamique des masses d'eau et les flux de transit semblent favoriser un comblement et/ou des limitations de renouvellement d'eau mettant en péril la durabilité de l’environnement de cette lagune Miquelonnaise. La Préfecture de Saint Pierre et Miquelon et la DTAM, en soutien à la gestion durable de cet environnement, ont sollicité l’Ifremer pour l’évaluation des flux d’alimentation de cette lagune. Une mission sur place a été réalisée en juin 2016, pour coordonner les actions et effectuer un certain nombre de mesures préliminaires (jaugeages et bathymétrie du chenal, courantométrie horizontale). Ces données sont complétées par une acquisition continue des vitesses de courant, avec des données disponibles à ce jour du 2 juin au 15 novembre 2016....
Tipo: Text
Palavras-chave: Hydrodynamique; Renouvellements; Saint-Pierre et Miquelon; Lagune; Grand Barachois; Hydrodynamic; Renewal rates; Saint Pierre and Miquelon; Lagoon; Grand Barachois.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00384/49512/50021.pdf

Spatial and temporal variations in trace metal concentrations in surface sediments of the Marennes Oleron Bay. Relation to hydrodynamic forcing
Provedor de dados: 5
Autores: Strady, Emilie; Kervella, Stephane; Blanc, Gerard; Robert, Serge; Stanisiere, Jean-yves; Coynel, Alexandra; Schaefer, Joerg.
Sediments quality assessment is of priority concern to provide a comprehensible overview of ecological and chemical state of an ecosystem. The Marennes-Oleron Bay, hosting the largest oyster production in France, is influenced by the historic polymetallic pollution of the Gironde Estuary. Despite, management efforts and decreasing emissions in the Gironde watershed, Cd levels in oysters from the bay are close to consumption limit (5 pig g(-1) dw. EC no. 466/2001). In this context, the aim of the study was to assess the priority metal (Ni, Cu, Zn, As, Ag, Cd, Hg, Pb and Th) concentrations in sediment within the Bay, by investigating spatial and temporal distribution variations and the role of hydrodynamic forcing. For that we selected three sites (east,...
Tipo: Text
Palavras-chave: Trace metal; Marennes Oleron Bay; Enrichment factor; Sediment; Hydrodynamic; Altus.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00038/14914/15996.pdf

Caractérisation numérique et expérimentale des effets d'interaction entre une hydrolienne et le milieu marin
Provedor de dados: 5
Autores: Maganga, Fabrice.
This work aims to characterise by the means of expérimental and numerical modeling, the behavior of marine current turbine and the characteristics of the wake generated under realistic inflow conditions. For that purpose, we used a tri-bladed horizontal axis turbine of 0.7 m of diameter. Particular attention is paid to the flow characteristic effects on the efficiency of the turbine, but also on the generated wake. Tests are carried out in the Ifremer wave and current flume tank in Boulogne-sur-Mer and in the towing tank of Brest, taking into account current profils, upstream turbulence intensity level and disturbances generated by wave/current interaction. The development of a three-dimensional software based on vortex methods, taking into account the non...
Tipo: Text
Palavras-chave: Hydrodynamique; Essais expérimentaux; Méthodes Vortex; Hydrolienne; Sillage.; Hydrodynamic; Experimental trials; Vortex Methods; Marine Current Turbine; Wake.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00170/28153/26384.pdf

The relationship between sandy beach nematodes and environmental characteristics in two Brazilian sandy beaches (Guanabara Bay, Rio de Janeiro)
Provedor de dados: 42
Autores: MARIA,TATIANA F.; PAIVA,PAULO; VANREUSEL,ANN; ESTEVES,ANDRÉ M.
We investigated if the differences in density and nematode communities of intertidal sediments from two Brazilian sheltered sandy beaches were related to environmental characteristics. The upper tide level (UTL) and the low tide level (LTL) of both beaches were surveyed in January (austral summer) and June 2001 (austral winter) during low-spring tides, by collecting samples of nematodes and sediments. Differences in density between beaches, tidal level and seasons, and nematode community structure were investigated. Sediments from both beaches were composed of medium to very coarse sand. The highest nematode densities were found at the UTL, and significant differences between beaches, tidal levels and months were found. A total of 54 genera were found and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Brazil; Free-living marine nematodes; Hydrodynamic; Granulometry; Sandy beach.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652013000100257

Hydrodynamic behavior of a lab-scale upflow anaerobic sludge blanket reactor (UASB) operated with an adopted hydraulic retention time (HRT) of 12 hours
Provedor de dados: 64
Autores: Lourenço,Aguinaldo Menegassi Pereira; Campos,Cláudio Milton Montenegro.
The present research was carried out in the Laboratory of Water Analysis at the Engineering Department at Federal University of Lavras (LWAED-UFLA), in order to evaluate the hydrodynamic behavior of a lab-scale upflow anaerobic sludge blanket reactor (UASB) that was continuously fed with liquid effluent from swine manure with solid separation over 2mm. The hydrodynamic parameters were determined by a tracer study, under hydraulic retention time (HRT) of 12 hours, using Lithium Chloride (LiCl) as a tracer. The system was monitored periodically through physical analysis of samples collected at UASB, during the steady-state operational conditions. The physical-chemical analyses were accomplished using a flame photometry. The operational average temperature in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hydrodynamic; Hydraulic retention time; Tracer studies; UASB reactor.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542009000400027