Consulta: subjectFacets:"Hydrodynamics"
Registros recuperados: 53
Data/hora: 01/06/2024 14:28:05

Typology of hydrological structures modelled and observed over the Bay of Biscay shelf
Provedor de dados: 5
Autores: Planque, Benjamin; Lazure, Pascal; Jegou, Anne-marie.
Collecting hydrological observations over the whole Bay of Biscay continental shelf can require several weeks. As a result, the observations are not truly synoptic and the interpretation of hydrological structures is corrupted by the time-lags between observations at distinct locations. We evaluated the effects of non-synoptic sampling during a spring cruise (17 April to 13 May 2000), using outputs from 3D hydrodynamic models as a substitute for true synoptic sampling. We developed a method for clustering hydrological regions based on the vertical structure of the water column and temporal changes in hydrography. In parallel, outputs from the 3D model were compared with field observations. The results show that in spring 2000 the Bay of Biscay continental...
Tipo: Text
Palavras-chave: Typology; Spatial temporal interactions; Hydrodynamics; Clustering analysis; Bay of Biscay.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-3959.pdf

How do microalgae perceive light in a high-rate pond? Towards more realistic Lagrangian experiments
Provedor de dados: 5
Autores: Demory, David; Combe, Charlotte; Hartmann, Philipp; Talec, Amelle; Pruvost, Eric; Hamouda, Raouf; Souille, Fabien; Lamarea, Pierre-olivier; Bristeau, Marie-odile; Sainte-marie, Jacques; Rabouille, Sophie; Mairet, Francis; Sciandra, Antoine; Bernard, Olivier.
Hydrodynamics in a high-rate production reactor for microalgae cultivation affects the light history perceived by cells. The interplay between cell movement and medium turbidity leads to a complex light pattern, whose forcing effects on photosynthesis and photoacclimation dynamics are nontrivial. Hydrodynamics of high density algal ponds mixed by a paddle wheel has been studied recently, although the focus has never been on describing its impact on photosynthetic growth efficiency. In this multidisciplinary downscaling study, we first reconstructed single cell trajectories in an open raceway using an original hydrodynamical model offering a powerful discretization of the Navier-Stokes equations tailored to systems with free surfaces. The trajectory of a...
Tipo: Text
Palavras-chave: Photosynthesis; Hydrodynamics; Modelling; Photoacclimation; Dunaliella salina; Non-photochemical quenching.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00445/55692/57352.pdf

Mineral and organic soluble forms of zinc, iron and copper: Distribution in the Seine Estuary.
Provedor de dados: 5
Autores: Gandon, R; Guegueniat, P; Fischer, J; Wartel, M.
One characteristic of the Seine Estuary system is the process of sediment resuspension by the specific hydrodynamics of this environment. It's the main factor of trace metals transport. Autotrophic activities also have an effect on the estuary, by pH variation. The behavior of soluble and organic copper, iron, have been studied in relation to salinity in and out of the estuary. The results are compared with those of other estuaries.
Tipo: Text
Palavras-chave: Hydrodynamics; Physicochemical properties; Water properties; Dissolved organic matter; Biogeochemical cycle; Resuspension; Metals; Suspended particulate matter.
Ano: 1985
URL: http://archimer.ifremer.fr/doc/1985/acte-1300.pdf

La Baie de Seine: Peuplements et especes benthiques en regime perturbe
Provedor de dados: 5
Autores: Cabioch, L; Retiere, C.
The waters of the Seine River are polluted by urban, industrial and agricultural effluents. In addition direct industrial wastes inputs are emptied into the estuary. Within the limits of the Seine Bay program it was not possible to research pollution impacts on every estuarine ecosystem link; so only benthos have been studied. To take time response of organisms into account, the authors have defined indicators or quantitative evaluation of parameters, reflecting physiological state. They have studied population fluctuations caused by natural or man induced effects.
Tipo: Text
Palavras-chave: Hydrodynamics; Population dynamics; Population structure; Bioaccumulation; Pollution effects; Marine pollution; Ecosystem disturbance; Benthos.
Ano: 1985
URL: http://archimer.ifremer.fr/doc/1985/acte-1304.pdf

On the experimental study of the flow around a fishing net
Provedor de dados: 5
Autores: Pichot, Geraldine; Germain, Gregory; Priour, Daniel.
Selectivity of fishing gears like trawls is obviously conditioned by the fish behaviour but also by the net and the flow. As well, flow may affect fish behaviour. With the aim of a better understanding of the flow in presence of a net and a catch, we suggest, through the experimental study below, to determine and to analyze the flow over a rigid cod-end in two configurations: with a closed and an open net entrance. Trials took place in a free surface flume tank and the flow characteristics were determined from velocity measurements obtained by laser velocimetry (inside, outside and through the meshes of the stiff cod-end). The experimental device, the measures and their analyzes are given here.
Tipo: Text
Palavras-chave: Turbulence; Laser velocimetry; Fluid structure interactions; Experimental study; Hydrodynamics; Fluid mechanics.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-4701.pdf

Dynamique des sédiments fins et mixtes des zones intertidales de la baie de Marennes-Oléron
Provedor de dados: 5
Autores: Kervella, Stephane.
This thesis aims at increasing the general knowledge on sediment dynamics of intertidal flats in the Marennes-Oléron Bay, according to physical, biological and anthropogenic factors.  The conducted research is compound of three complementary studies: (1) a study of sediment behaviour through applied rheophysics on intertidal superficial sediments; (2) a hydro-sedimentary study based on identification of the forcing action (physical, biological or anthropogenic) on the intertidal flat stability over several time scales (from the event to several months); (3) a specific application of the model SiAM-2DH to the Marennes-Oléron Bay.  The surface sediments shows a mechanical behaviour that mainly depends on the fine fraction for a composition that contains up...
Tipo: Text
Palavras-chave: Rhéophysique; Seuil d’écoulement; Sédiments cohésifs et mixtes; Sédimentation; Érosion; Hydrodynamique; Vasière; Zone intertidale; Conchyliculture; ALTUS; SiAM-2DH; Baie de Marennes-Oléron; Rhéophysics; Shear strenght; Cohesive and mixed sediment; Sédimentation; Erosion; Hydrodynamics; Mudflat; Intertidal area; Oyster; ALTUS; SiAM-2DH; Marennes-Oléron Bay.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00004/11534/8117.pdf

Hydrodynamic characterization of the Arcachon Bay, using model-derived descriptors
Provedor de dados: 5
Autores: Plus, Martin; Dumas, Franck; Stanisiere, Jean-yves; Maurer, Daniele.
A numerical model (MARS-2D) was developed, with the aim of describing the hydrodynamics that prevail in Arcachon Bay. Direct model results as well as derived mixing and transport time-scales (tidal prism, local and integrated flushing times, age of water masses), were used to understand the behaviour of water masses and exchanges between the Bay and its frontiers. Particular attention was paid to the processes that drive the hydrodynamics (tides, wind and rivers), in order to understand their respective influence. The Arcachon Bay hydrodynamic system appears primarily to be highly influenced by tides; secondarily, by winds. About two third of the lagoon total volume is flushed in and out at each tidal cycle, which represent a mean tidal prism of 384...
Tipo: Text
Palavras-chave: Arcachon Bay; Tracer; Age of seawater; Flushing time; Tidal prism; Residual fluxes; Hydrodynamics.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6424.pdf

In situ record of sedimentary processes near the Rhone River mouth during winter events (Gulf of Lions, Mediterranean Sea)
Provedor de dados: 5
Autores: Marion, C.; Dufois, Francois; Arnaud, Mireille; Vella, C.
The environment is impacted by natural and anthropogenic disturbances that occur at different spatial and temporal scales, and that lead to major changes and even disequilibria when exceeding the resiliency capacities of the ecosystem. With an annual mean flow of 1700 m(3) s(-1), the Rhone River is the largest of the western Mediterranean basin. Its annual solid discharges vary between 2 and 20 Mt, with flood events responsible for more than 70% of these amounts. In the marine coastal area, close to the mouth, both flocculation and aggregation lead to the formation of fine-grained deposits, i.e. the prodelta. This area is characterized by sediment accumulation rates up to 20-50 cm yr(-1) and high accumulations of particle reactive contaminants such as...
Tipo: Text
Palavras-chave: Sediment dynamics; Floods; Hydrodynamics; Radiotracers; Rhone River prodelta.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00006/11695/8479.pdf

Phase-averaged mean properties of turbulent flow developing around a fluttering sheet of net
Provedor de dados: 5
Autores: Bouhoubeiny, Elkhadim; Druault, Philippe; Germain, Gregory.
Time-Resolved Particle Image Velocimetry (PIV) measurements are performed to investigate the hydrodynamic flow interaction with a representative piece of fishing net structure. Using the advanced post-processing mathematical tool based on Proper Orthogonal Decomposition, the phase averaged mean properties of turbulent flows are extracted from PIV database, demonstrating the existence of a Turbulent Boundary Layer (TBL) flow developing all around the sheet of net. The results also show that the mesh opening and so the turbulent flow passing through the structure are strongly influenced by the structure oscillations. This work allows us to demonstrate that the drag computation of fishing gear, commonly based on uniform velocity, needs to consider not only...
Tipo: Text
Palavras-chave: Fishing net structure; Hydrodynamics; PIV; Turbulent boundary layer flow.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00184/29552/27878.pdf

Small-scale effects of hydrodynamics on the structure of intertidal macroalgal communities: A novel approach
Provedor de dados: 5
Autores: Burel, Thomas; Schaal, Gauthier; Grall, Jacques; Le Duff, Michel; Chapalain, Georges; Schmitt, Blondie; Gemin, Maxence; Boucher, Olivier; Ar Gall, Erwan.
Wave height was used as a proxy to assess the effect of hydrodynamics on the development and structure of intertidal North-East Atlantic rocky macroalgal communities (Brittany). The characterization of hydrodynamics at small-scale (about 10 m) was performed through wave height in situ monitoring using pressure sensors. Both the diversity and the cover of the macroalgal communities were sampled in parallel. Wave heights exhibit large variations with values ranging from ca. 5 cm to 1.60 m. We show that wave height directly controls the cover of macroalgal canopies (Pearson's r between −0.62 and −0.39). In all communities, most of the fucoid covers regressed with increasing wave height values. By contrast, positive correlations were found at low shore levels...
Tipo: Text
Palavras-chave: Macroalgal communities; Intertidal zone; Rocky shores; Wave heights; Hydrodynamics; Mini-diver; Brittany.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00506/61769/65752.pdf

Trophic relationships between benthic or planktonic microphytes and infaunal bivalve molluscs
Provedor de dados: 5
Autores: Plantecuny, M; Bodoy, Alain.
In order to estimate energetic relationship, microphytic and benthic bivalve levels of a shallow (1.5 m), sandy ecosystem near Marseille (Gulf of Fos, Southern France) were sampled monthly during 1.5 year, in two sites differing by their wave exposure. In the sheltered area, the bivalve Ruditapes decussatus was the dominant species, while another bivalve, Donax trunculus , was found in the open, wave exposed site. Chlorophyll a and primary production of the phytoplankton and the microphytobenthos, as well as population dynamic, growth and biochemical composition of bivalves (lipids, proteins and carbohydrates) were monitored.
Tipo: Text
Palavras-chave: Ruditapes decussatus; Bivalvia; Periphyton; Phytoplankton; Biochemical composition; Growth; Marine molluscs; Hydrodynamics; Seasonal variations; Primary production; Trophic relationships.
Ano: 1984
URL: http://archimer.ifremer.fr/doc/1984/acte-1528.pdf

A potential flow based flight simulator for an underwater glider
Provedor de dados: 5
Autores: Phoemsapthawee, Surasak; Le Boulluec, Marc; Laurens, Jean-marc; Deniset, Francois.
Underwater gliders are recent innovative types of autonomous underwater vehicles (AUVs) used in ocean exploration and observation. They adjust their buoyancy to dive and to return to the ocean surface. During the change of altitude, they use the hydrodynamic forces developed by their wings to move forward. Their flights are controlled by changing the position of their centers of gravity and their buoyancy to adjust their trim and heel angles. For better flight control, the understanding of the hydrodynamic behavior and the flight mechanics of the underwater glider is necessary. A 6-DOF motion simulator is coupled with an unsteady potential flow model for this purpose. In some specific cases, the numerical study demonstrates that an inappropriate stabilizer...
Tipo: Text
Palavras-chave: Underwater glider; Hydrodynamics; Potential flow; 6DOF; Newton-Euler equation; AUVs.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00171/28227/26480.pdf

Sediment and water movement in coastal embayments.
Provedor de dados: 5
Autores: Collins, M.
The investigations described in this report relating to Swansea Bay and Thermaicos Bay demonstrate that processes which take place in embayments, particularly those concerned with water and sediment movement, representing only a constituent part of a much larger transport system.
Tipo: Text
Palavras-chave: Coastal zone; Sediment transport; Tidal motion; Wave motion; Hydrodynamics; Bays; Water motion; Sediment movement.
Ano: 1985
URL: http://archimer.ifremer.fr/doc/1985/acte-1286.pdf

Mass mortalities of Pacific oysters Crassostrea gigas reflect infectious diseases and vary with farming practices in the Mediterranean Thau lagoon, France
Provedor de dados: 5
Autores: Pernet, Fabrice; Barret, Jean; Le Gall, Patrik; Corporeau, Charlotte; Degremont, Lionel; Lagarde, Franck; Pepin, Jean-francois; Keck, Nicolas.
Experiments were conducted to investigate the effects of farming sites, seeding date, age of oysters, ploidy level and rearing structures on mortality, pathogens and energetic reserves of oysters Crassostrea gigas. Mortality of oysters coincided with infections involving, primarily, the ostreid herpesvirus OsHV-1 and, secondarily, bacteria of the group Vibrio splendidus, when seawater temperature was between 17 and 24°C. Mortality started in early May and lasted until late September, with an interruption in July and August when seawater temperatures rose above 24°C. Mortality varied with farming site: oysters maintained in the open Mediterranean Sea showed no mortality and OsHV-1 was occasionally detected at a low level only, while oysters maintained in...
Tipo: Text
Palavras-chave: Pacific oyster; Mortality; Disease; Farming practices; Hydrodynamics; Energetic.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00086/19739/17379.pdf

Sur l'hydrodynamique de la Baie de Seine. Resultats d''observations et de modelisations
Provedor de dados: 5
Autores: Leprovost, C; Fornerino, M; Villaret, C.
Study of Seine bay hydrodynamics can't be separated from the Channel and continental shelf. The authors' modellings are aimed at the study of this global ladder and the insertion of coastal areas such as the Seine Bay in this context. Two 2-D models are used. One covers only the Channel, and the other from Pas-de-Calais to continental shelf limits including Celtic sea, Channel and southern North Sea. The results are comparated with long time current observations.
Tipo: Text
Palavras-chave: Current data; Mathematical models; Modelling; Tidal currents; Current prediction; Water circulation; Hydrodynamics.
Ano: 1985
URL: http://archimer.ifremer.fr/doc/1985/acte-1259.pdf

General hydrodynamical features in the ligurian sea inferred from the dyome experiment
Provedor de dados: 5
Autores: Taupier-letage, Isabelle; Millot, Claude.
Tipo: Text
Palavras-chave: Hydrodynamique; Mer Ligure; Circulation générale; Moyenne échelle; Variabilité; Hydrodynamics; Ligurian Sea; General circulation; Mesoscale; Variability.
Ano: 1986
URL: http://archimer.ifremer.fr/doc/00110/22125/19761.pdf

Coastal phytoplankton community dynamics and coexistence driven by intragroup density-dependence, light and hydrodynamics
Provedor de dados: 5
Autores: Barraquand, F.; Picoche, C.; Maurer, Daniele; Carassou, L.; Auby, Isabelle.
Phytoplanktonic communities maintain a high diversity in a seemingly homogeneous environment, competing for the same set of resources. Many theories have been proposed to explain this coexistence despite likely competition, such as contrasted responses to temporal environmental variation. However, theory has developed at a faster pace than empirical evaluation using field data, which requires inferring drivers of community dynamics from observational time series. Here, we combine autoregressive models with a data set spanning more than 20 years of phytoplankton counts every two weeks, together with nutrients and physical variables. By comparing models dominated by nutrients or physical variables (hydrodynamics and climate), we first explore which abiotic...
Tipo: Text
Palavras-chave: Competition; Diatoms; Dinoflagellates; Hydrodynamics; Interactions; MAR; Mutualism; Network; Population dynamics; Seasonality; Time series.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00461/57257/59285.pdf

Accumulation des sels nutritifs dans un sédiment lagunaire et environnement hydrodynamique
Provedor de dados: 5
Autores: Gomez, E; Millet, B; Picot, B.
The Mejean-Perols Lagoon is situated on the French Mediterranean coast. It is a small (747 ha) and shallow (70 cm) lagoon. Some treated effluent from Montpellier flows into this hypereutrophic lagoon. The cartography of C, N and P concentrations in the sediment was studied based on 35 bottom samples. The nitrogen and organic carbon concentrations were more or less homogeneous, the highest concentrations being found in the middle of the lagoon. The phosphate was principally bound onto the sediment in the west zone. The observed distribution was independent of grain size, the distribution of which was rather homogeneous. In this lagoon water circulation is wind induced. Four different water flow structures were observed, as functions of the prevailing winds...
Tipo: Text
Palavras-chave: Sédiment; Lagune côtière; Hydrodynamique; Sels nutritifs; Carbone; Sediment; Coastal lagoon; Hydrodynamics; Nutrients; Carbon.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00325/43642/43247.pdf

Rejets urbains. Volet Manche - Atlantique - Site de Morlaix - Etudes sédimentologique et Bathymétrique de l' estuaire de Morlaix
Provedor de dados: 5
Autores: Bassoullet, Philippe; L'Yavanc, Jacky; Guillaud, Jean-francois; Loarer, Ronan; Breton, Marguerite.
In order to increase our knowledge about sediment transport in the bay and maritime part of the River of Morlaix (Finistère), measurernènts have been perforrned on site. This report gives the granulometrical and physical parameters of the sediments as weIl as the hydrodynamics, used for a model of particulate transport in the area. The rnodel and its application will be published later
Tipo: Text
Palavras-chave: Rejet urbain; Sédiment; Granulométrie; Hydrodynamique; Modèle de transport particulaire; Sable; Vase; Estuaire de Morlaix.; Urban wastes; Model; Sediment; Granulometry; Hydrodynamics; Sand; Mud; Sedimentary transport model; Morlaix estuary.
Ano: 1987
URL: http://archimer.ifremer.fr/doc/00345/45658/45293.pdf

Atlas thématique de l'environnement marin en baie de Saint-Brieuc (Côtes-d'Armor)
Provedor de dados: 5
Autores: Augris, Claude; Hamon, Dominique.
This atlas presents in a synthetic form the hydrodynamical, geological and biological characteristics of one of the most studied region of the French littoral. Geologic and geophysical data of the Saint-Brieuc Bay show that the deep basement consists of pre-palaeozoic or palaeozoic sedimentary series in the centre of the Bay, whereas metamorphic and magmatic formations are dominant in coastal regions. The location of superficial sediments in the Bay, is mainly due to marine currents. A granulometric gradient, from very fine to coarse sediments, appears in two directions: from the coast towards the high sea, and from the west to the east. Rocky substrates disrupt the sediment distribution, with, most of the time, a concentration of coarse sediments near the...
Tipo: Text
Palavras-chave: Atlas; Bathymetry; Bottom topography; Commercial species; Geomorphology; Hydrodynamics; Marine resources; Sediment analysis; Sedimentary basins; Zoobenthos.
Ano: 1996
URL: http://archimer.ifremer.fr/doc/00031/14246/11527.pdf

Coastal hydrodynamics in a windy lagoon
Provedor de dados: 5
Autores: Alekseenko, Elena; Roux, Bernard; Sukhinov, A.; Kotarba, R.; Fougere, D.
The nonlinear hydrodynamics (3D RANS model) in a wide semi-enclosed windy lagoonal ecosystem is accurately investigated in the context of analyzing the limiting conditions of the recovery of submerged aquatic vegetation (SAV). Among the main natural hydrodynamical forcings, we consider the wind effect. We mainly focus attention to characteristic velocities (free surface and bottom) and to free surface elevation in the nearshore regions (with shallow water) where SAV were severely damaged in the past decades. Our main result relates to wind effects that form downwind coastal jets, alongshore, in shallow water areas, due to Berre bathymetry. Such coastal jets, which were never described previously in Berre lagoon literature, give rise to substantial bottom...
Tipo: Text
Palavras-chave: Hydrodynamics; Berre lagoon; Current structures; Zostera noltii; Seagrass protection.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00144/25511/24704.pdf

Etude expérimentale pour l'optimisation des performances d'une plage d'amortissement parabolique
Provedor de dados: 5
Autores: Le Boulluec, Marc; Kimmoun, Olivier; Molin, Bernard.
An optimisation study was run before rebuilding the damping beach of the Ifremer Ocean Engineering Basin. Trials were conducted at a ¼ geometrical scale at Ecole Centrale de Marseille in a wave tank reproducing the original performance of the beach. A series of modifications was studied : incidence, device between the beach and the adjacent wall, porosity. Porosity was shown as the most efficient tool to enhance the beach absorption and full scale measurements revealed that the resulting damping coefficient was less than 10 % for all usual periods and amplitudes.
Tipo: Text
Palavras-chave: Hydrodynamique; Essais en bassin; Houle; Réflexion; Amortissement; Plage; Hydrodynamics; Wave tank testing; Reflection; Damping beach.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/00170/28170/26404.pdf

Modelling the spatial heterogeneity of ecological processes in an intertidal estuarine bay: dynamic interactions between bivalves and phytoplankton
Provedor de dados: 5
Autores: Grangere, Karine; Lefebvre, Sebastien; Bacher, Cedric; Cugier, Philippe; Menesguen, Alain.
Spatial patterns in ecological communities result from a combination of physical and biological factors. In an estuarine intertidal bay, spatial differences have been found in the structure of phytoplanktonic communities and in the biological performance of cultivated oysters. It has been hypothesised that trophic heterogeneity exists, although the mechanisms controlling it remain undefined. Spatial and temporal interactions in the structure of phytoplanktonic biomass and in the biological performance of cultivated oysters were highlighted in this estuarine intertidal bay using a 2-dimensional hydrodynamic model coupled to a nutrient-phytoplankton-zooplankton bivalve food web model. The coupled models allowed a reproduction in space and time of variations...
Tipo: Text
Palavras-chave: Spatial heterogeneity; Hydrodynamics; Ecosystem model; Food supply; Bivalves; Dynamic energy budget model; Physiological status; Baie des Veys.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00017/12854/9819.pdf

Dynamique des eaux (en Baie de Seine): Synthese des discussions
Provedor de dados: 5
Autores: Chabertd'Hieres, G.
The discussions about "water dynamics" have dealt with the knowledge of long-term water mass circulation (from several days to several months), by the effects of three parameters: tides near limits and in the Seine Bay, turbid freshwater discharge (Seine river) and winds. This communication gives information about Eulerian and Lagrangian drift, used for residual current exhibition.
Tipo: Text
Palavras-chave: Lagrangian current measurement; Eulerian current measurement; Mathematical models; Coastal zone; Residual flow; Hydrodynamics.
Ano: 1985
URL: http://archimer.ifremer.fr/doc/1985/acte-1271.pdf

Analysis and visualization of the glass eel behavior (Anguilla anguilla) in the Adour estuary and estimate of its upstream migration speed
Provedor de dados: 5
Autores: Prouzet, Patrick; Odunlami, Marc; Duquesne, Elise; Boussouar, Ahmed.
The studies carried out on the Adour estuary on the migration of glass eels lead to the characterisation of their swimming behavior. Individuals migrate passively with the flood tide current behind the dynamic tide front, and their movements into the water column are linked to the surrounding luminosity and water turbidity. A numerical model was built from observations gathered on glass eel densities during scientific surveys. It uses the outputs of a hydrodynamic model accounting for the variations in the river flow and tide coefficient. It allows the simulation of the displacement of a particle in the longitudinal axis of the estuary. The variation of the vertical movements through the water column takes into account the cloud cover, the moon phases, the...
Tipo: Text
Palavras-chave: Numerical modeling; Fish behavior; Migration; Estuary; Hydrodynamics; Exploitation rate; Glass eel; Anguilla anguilla; Atlantic Ocean.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00000/11171/7531.pdf

The Alderney Race: General hydrodynamic and particular features
Provedor de dados: 5
Autores: Bailly Du Bois, P; Dumas, Franck; Morillon, M; Furgerot, L; Voiseux, C; Poizot, E; Mear, Y; Bennis, Anne-claire.
This study presents an overview of the main hydrodynamic features of the Alderney Race strait based on in-situ measurements and 2D hydrodynamic model simulations. The strait encompasses a large amplitude of tidal properties (tidal range and tidal wave propagation) and particularly strong currents exceeding 5 m.s-1 with associated counter currents and gyres. Variations in depth, sea bottom roughness, coastal topography and current orientation around the La Hague Cape provide access to a large variety of original hydrodynamic regimes. Some are revealed as locations with a 0.4 m drop in the mean sea level associated with strong average currents. A resonance effect associated with the offshore currents can also be observed close to the coasts. The "St Martin...
Tipo: Text
Palavras-chave: Alderney Race; La Hague Cape; Current; Tide; Hydrodynamics; Model.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00641/75286/75639.pdf

Environmental factors controlling biomass development of seagrass meadows of Zostera noltei after a drastic decline (Arcachon Bay, France)
Provedor de dados: 5
Autores: Cognat, Mathis; Ganthy, Florian; Auby, Isabelle; Barraquand, Frederic; Rigouin, Loic; Sottolichio, Aldo.
The relative impact of light, depth, hydrology, hydrodynamics, sediment and nutrients on growth of the seagrass Zostera noltei was investigated in Arcachon Bay, where the extent of seagrass beds has been decreasing for 20 years. A comprehensive multi-parameter survey of 9 sites was conducted monthly over one year. A three-parameter logistic growth model was fitted to biomass data to unravel the relative contributions of environmental factors on seagrass growth. The present study highlights the fact that, in addition to the dominant positive effect of light on plant growth, the hydrological and hydrodynamic parameters were important drivers for Z. noltei growth at the scale of the whole Bay. At the scale of individual sites, other factors such as macroalgal...
Tipo: Text
Palavras-chave: Physical parameters; Light; Hydrodynamics; Adaptation; Statistical growth model.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00451/56229/57789.pdf

Circulation and suspended sediment transport in a coral reef lagoon: The south-west lagoon of New Caledonia
Provedor de dados: 5
Autores: Ouillon, S.; Douillet, Pascal; Lefebvre, J. P.; Le Gendre, Romain; Jouon, Aymeric; Bonneton, P.; Fernandez,; Chevillon, C.; Magand, O.; Lefevre, J.; Le Hir, Pierre; Laganier, R.; Dumas, Franck; Marchesiello, P.; Madani, A. Bel; Andrefouet, S.; Panche, J. Y.; Fichez, R.
The south-west lagoon of New Caledonia is a wide semi-open coral reef lagoon bounded by an intertidal barrier reef and bisected by numerous deep inlets. This paper synthesizes findings from the 2000-2008 French National Program EC2CO-PNEC relative to the circulation and the transport of suspended particles in this lagoon. Numerical model development (hydrodynamic, fine suspended sediment transport, wind-wave, small-scale atmospheric circulation) allowed the determination of circulation patterns in the lagoon and the charting of residence time, the later of which has been recently used in a series of ecological studies. Topical studies based on field measurements permitted the parameterisation of wave set-up induced by the swell breaking on the reef barrier...
Tipo: Text
Palavras-chave: Hydrodynamics; Suspended sediment; New Caledonia; Coral reef lagoon; Sediment; Turbidity; Resuspension.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00014/12526/9401.pdf

Contribution de l''etude des suspensions a la comprehension des mecanismes hydrosedimentaires estuariens et littoraux en Manche centrale et orientale
Provedor de dados: 5
Autores: Dupont, J; Lafite, R; Lamboy, M.
Satellite imagery shows the turbid and thermal plume of the Seine River and littoral zone of Picardie and Haute-Normandie. The suspensions have been analysed in conformity with a strategy elaborated in 1985 by the authors. In this macrotidal coastal environment they have attempted to draw the dynamic specificities and the material characteristics.
Tipo: Text
Palavras-chave: Estuarine front; Harbours; Coastal zone; Estuaries; Marine environment; Composition; Particle concentration; Granulometry; Hydrodynamics; River plumes; Suspended particulate matter.
Ano: 1985
URL: http://archimer.ifremer.fr/doc/1985/acte-1277.pdf

Suspended Sediment Dynamics in the Macrotidal Seine Estuary (France) - Part 1: Numerical Modeling of Turbidity Maximum Dynamics
Provedor de dados: 5
Autores: Grasso, Florent; Verney, Romaric; Le Hir, Pierre; Thouvenin, Benedicte; Schulz, Elisabeth; Kervella, Youenn; Fard, I. Khojasteh Pour; Lemoine, J. -p.; Dumas, Franck; Garnier, Valerie.
Tidal pumping, baroclinic circulation and vertical mixing are known to be the main mechanisms responsible for the estuarine turbidity maximum (ETM) formation. However, the influence of hydro-meteorological conditions on ETM dynamics is still not properly grasped and requires further investigation to be quantified. Based on a realistic 3-dimensional numerical model of the macrotidal Seine Estuary (France) that accounts for mud and sand transport processes, the objective of this study is to quantify the influence of the main forcing (river flow, tides, waves) on the ETM location and mass changes. As expected, the ETM location is strongly modulated by semidiurnal tidal cycles and fortnightly timescales with a high sensitivity to river flow variations. The ETM...
Tipo: Text
Palavras-chave: Estuary; Mud; Sand; Hydrodynamics; Turbidity maximum; Waves; Measurement; Modeling.
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00416/52770/53638.pdf

Scenarios of fish waste deposition at the sub-lagoon scale: a modelling approach for aquaculture zoning and site selection
Provedor de dados: 5
Autores: Chary, Killian; Callier, Myriam; Coves, Denis; Aubin, Joel; Simon, Julien; Fiandrino, Annie.
Spatial planning, including zoning and site-selection steps, is necessary to determine locations that minimize environmental impacts of aquaculture and respect ecosystem carrying capacities. This study aimed to analyse potential benthic waste deposition in a broad range of fish farming situations to facilitate zoning. To this end, we simulated waste dispersion for 54 aquaculture scenarios combining three red drum (Sciaenops ocellatus) farm types (Small, Medium, and Large) based on real farm characteristics and 36 sites with contrasting hydrodynamics in Mayotte’s North-East Lagoon. Key forcing variables and parameters of the particle-dispersion model for farms (layout and solid waste fluxes), species (feed- and faeces-settling velocities) and sites (depth...
Tipo: Text
Palavras-chave: Aquaculture zones; Carrying-capacity; Environmental impact; Hydrodynamics; NewDEPOMOD; Particle dispersion; Red drum; Scenario analysis.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00666/77810/79985.pdf

Spatial epidemiological modelling of infection by Vibrio aestuarianus shows that connectivity and temperature control oyster mortality
Provedor de dados: 5
Autores: Lupo, Coralie; Dutta, Bhagat Lal; Petton, Sebastien; Ezanno, P; Tourbiez, Delphine; Travers, Marie-agnes; Pernet, Fabrice; Bacher, Cedric.
Vibrio aestuarianus infection in oyster populations causes massive mortality, resulting in losses for oyster farmers. Such dynamics result from host-pathogen interactions and contagion through water-borne transmission. To assess the spatiotemporal spread of V. aestuarianus infection and associated oyster mortality at a bay scale, we built a mathematical model informed by experimental infection data at 2 temperatures and spatially dependent marine connectivity of oyster farms. We applied the model to a real system and tested the importance of each factor using a number of modelling scenarios. Results suggest that introducing V. aestuarianus in a fully susceptible adult oyster population in the bay would lead to the mortality of all farmed oysters over 6 to...
Tipo: Text
Palavras-chave: Basic reproduction number; Crassostrea gigas; Hydrodynamics; Oyster disease; Sensitivity analysis; Vibrio aestuarianus.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00662/77459/79114.pdf

Wave and current flume tank of IFREMER at Boulogne-sur-mer. Description of the facility and its equipment
Provedor de dados: 5
Autores: Gaurier, Benoit; Germain, Gregory; Facq, Jean-valery; Bacchetti, Thomas.
This document presents the wave and current flume tank of IFREMER at Boulogne-sur-mer. This facility is unique in Europe because of its size and capabilities. The experimental working section is 4m wide by 2m deep and 18m long. Two pumps with a total power of 500kW enable the 700m3 of fresh water to move with a maximum velocity of 2.2m/s. Wave can be superimposed to the current using a dedicated wavemaker. It can be located at an upstream of downstream surface position in order to generate wave propagating with or against the current. Additional specific experimental devices are used in the laboratory as well, such as: Laser Doppler Velocimeter, Acoustic Doppler Velocimeter, Particles Image Velocimetry, underwater and aerial Qualysis Motion Tracking system...
Tipo: Text
Palavras-chave: Fluid mechanics; Hydrodynamics; Experimental trials; Wave and current flume tank; Ifremer; Boulogne-surmer.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00470/58163/60672.pdf

Importance et role du materiel organique vivant et inerte dans les suspensions de la Baie de Seine
Provedor de dados: 5
Autores: Dupont, J; Lafite, R.
Living and inert organic matter take an important place inside suspensions in Seine Bay. There particulate matter and the organo-mineral particles can induce granulometric modes, which constitute a determinant component for dynamics characterizing of suspensions. Organic fraction, in particular, plankton (diatoms and zooplankton) is a main factor in open sea which can concentrate when coming into contact with mass water fronts. Organo-mineral aggregates are present in all estuaries. Importance and action of this organic particulate matter are studied for a best knowledge of this ecosystem.
Tipo: Text
Palavras-chave: Zonal distribution; Estuaries; Species diversity; Plankton; Suspended inorganic matter; Sedimentation; Hydrodynamics; Suspended organic matter.
Ano: 1985
URL: http://archimer.ifremer.fr/doc/1985/acte-1278.pdf

Modélisation du transport sédimentaire et des interactions morphodynamiques par les courants de turbidité dans les canyons sous-marins. Application à la Méditerranée Occidentale
Provedor de dados: 5
Autores: Payo Payo, Marta.
Turbidity currents in submarine canyons are the main contribution for sediment transfer across the continental margins. Geological studies of submarine canyons and associated turbiditic systems for more than 30 years led to an extraordinary breakthrough in the understanding of how turbidite systems evolve. However, these studies remain limited to a posteriori interpretations, based on the distribution of deposits and morphological evidences. The overarching aim of this thesis is to apply a 2DH process-based model to simulate large-scale turbidity currents on two different submarine canyons in the western Mediterranean coast.The work in La Fonera canyon, in the Catalan margin, focuses on the modelling of sediment transport and accumulation resulting from...
Tipo: Text
Palavras-chave: Canyons sous-marins; Chalutage; Courants de turbidité; Forces de Coriolis; Hydrodynamique; Modélisation; Sédimentologie; Submarine canyons; Trawling; Turbidity current; Modelling; Hydrodynamics; Sedimentology; Coriolis forces.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00498/60919/64280.pdf

Probabilistic approach of water residence time and connectivity using Markov Chains with application to tidal embayments
Provedor de dados: 5
Autores: Bacher, Cedric; Filgueira, R.; Guyondet, T.
Markov Chain analysis was recently proposed to assess the time scales and preferential pathways into biological or physical networks by computing residence time, first passage time, rates of transfer between nodes and number of passages in a node. We propose to adapt an algorithm already published for simple systems to physical systems described with a high resolution hydrodynamic model. The method is applied to bays and estuaries on the Eastern Coast of Canada for their interest in shellfish aquaculture. Current velocities have been computed by using a 2 dimensional grid of elements and circulation patterns were summarized by averaging Eulerian flows between adjacent elements. Flows and volumes allow computing probabilities of transition between elements...
Tipo: Text
Palavras-chave: Transfer time; Transfer rate; Residual flow; Indicators; Aquaculture; Hydrodynamics.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00280/39124/37677.pdf

Making water flow: a comparison of the hydrodynamic characteristics of 12 different benthic biological flumes
Provedor de dados: 5
Autores: Jonsson, Per R.; Van Duren, Luca A.; Amielh, Muriel; Asmus, Ragnhild; Aspden, Rebecca J.; Daunys, Darius; Friedrichs, Michael; Friend, Patrick L.; Olivier, Frédéric; Pope, Nick; Precht, Elimar; Sauriau, Pierre-guy; Schaaff, Estelle.
Flume tanks are becoming increasingly important research tools in aquatic ecology, to link biological to hydrodynamical processes. There is no such thing as a "standard flume tank", and no flume tank is suitable for every type of research question. A series of experiments has been carried out to characterise and compare the hydrodynamic characteristics of 12 different flume tanks that are designed specifically for biological research. These facilities are part of the EU network BioFlow. The flumes could be divided into four basic design types: straight, racetrack, annular and field flumes. In each facility, two vertical velocity profiles were measured: one at 0.05 m s(-1) and one at 0.25 m s(-1). In those flumes equipped with Acoustic Doppler Velocimeters...
Tipo: Text
Palavras-chave: Methods; Hydrodynamics; Flume tanks; Biological physical interaction; Benthic boundary layer.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-2242.pdf

An Unstructured Numerical Model to Study Wind-Driven Circulation Patterns in a Managed Coastal Mediterranean Wetland: The Vaccares Lagoon System
Provedor de dados: 5
Autores: Boutron, Olivier; Bertrand, Olivier; Fiandrino, Annie; Hoehener, Patrick; Sandoz, Alain; Cherain, Yves; Coulet, Eric; Chauvelon, Philippe.
The spatiotemporal structure of wind-driven circulation patterns and associated water exchanges can drive important bio-hydrodynamic interactions in shallow lagoons. The Vaccares lagoon system is a complex shallow hydrosystem located in the central part of the Rhone Delta (France). It is internationally recognized as part of a biosphere reserve within the framework of UNESCO's Man and Biosphere Programme, and as a RAMSAR site. Due to its frequent occurrence in this area, and considering the shallowness of the Vaccares lagoon system, wind is assumed to play a major role in the hydrodynamic and biological processes. In this study, a hydrodynamic model was developed to investigate the structure of wind-driven circulations in the Vaccares lagoon system, to...
Tipo: Text
Palavras-chave: Coastal lagoon; Mathematical model; Hydrodynamics; Calibration; Validation; Wind-driven circulation.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00303/41382/40558.pdf

Can north american fish passage tools work for South american migratory fishes?
Provedor de dados: 83
Autores: Baigún,Claudio Rafael Mariano; Nestler,John Michael; Oldani,Norberto Oscar; Goodwin,R. Andrew; Weber,Larry J.
In North America, the Numerical Fish Surrogate (NFS) is used to design fish bypass systems for emigrating juvenile salmon as they migrate from hatchery outfalls and rearing habitats to adult habitat in the oceans. The NFS is constructed of three linked modules: 1) a computational fluid dynamics model describes the complex flow fields upstream of dams at a scale sufficiently resolved to analyze, understand and forecast fish movement, 2) a particle tracking model interpolates hydraulic information from the fixed nodes of the computational fluid model mesh to multiple locations relevant to migrating fish, and 3) a behavior model simulates the cognition and behavior of individual fish in response to the fluid dynamics predicted by the computational fluid...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hydraulic strain; Hydrodynamics; Numerical Fish Surrogate; Eulerian-Lagrangian-agent method.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252007000200004

The effect of the Mbita Causeway on water currents in the region of Rusinga Channel, Winam Gulf, Lake Victoria: a 3D modelling study with ELCOM
Provedor de dados: 20
Autores: Romero, J.R.; Khisa, P.
The Mbita Causeway in Kenya was constructed in the early 1980’s to link Rusinga Island to the mainland to facilitate the transport of people, goods, and services to the island. One of the effects of the Causeway was to permanently block a secondary connection between Rusinga Channel and the offshore waters of Lake Victoria. This secondary channel may have served as a substantial pathway of exchange between Winam Gulf and Lake Victoria prior to the Causeway. There has been considerable scientific and political debate as to whether decreased flushing within the two bays on either side of the Causeway has occurred and led to poorer lake water quality since the construction of the barrier. In Apr.-May 2005 an intensive field investigation was undertaken to...
Tipo: Proceedings Paper
Palavras-chave: Hydrodynamics; Water quality; Channel flow; Development projects; Simulation; Modelling; Flushing; Environmental effects; Water currents; Inland water environment; Hydrodynamics; Http://aims.fao.org/aos/agrovoc/c_3723.
Ano: 2006
URL: http://hdl.handle.net/1834/1473

Assessment of an environmental barrier to transport of ichthyoplankton from the southern to
Provedor de dados: 20
Autores: Lett, Christophe; Veitch, Jennifer; Van der Lingen, Carl D.; Hutchings, Larry.
The Lüderitz upwelling cell and Orange River cone (LUCORC) area, a transboundary region between South Africa and Namibia, is considered to be an environmental barrier to transport of ichthyoplankton from the southern to the northern Benguela upwelling ecosystems. We use environmental data and modelling to assess the potential mechanisms responsible for this barrier: environmental data were extracted from the 1 × 1° World Ocean Atlas 2001 database and used to build maps of annual mean salinity, temperature, chlorophyll, dissolved oxygen and nutrient concentrations; outputs of a regional circulation model were used in an individual-based model to assess the transport of passive particles from the southern to the northern Benguela. The data show no clear...
Tipo: Journal Contribution
Palavras-chave: Ichthyoplankton; Upwelling; Modelling; Coastal oceanography; Trade winds; Salinity; Hydrodynamics; Cartesian coordinates; Chlorophylls.
Ano: 2007
URL: http://hdl.handle.net/1834/4667

Modèle couple dynamique-écologie pour la lagune de Bizerte
Provedor de dados: 20
Autores: Béjaoui, B.; Harzallah, A.; Moussa, M.; Chapelle, A.
Ce travail porte sur le développement d’un modèle hydroécologique tridimensionnel basé sur deux éléments nutritifs l’azote et le phosphore. Le modèle hydrodynamique est forcé par des données climatiques mensuelles NOAA. Le modèle écologique a été développé en se basant sur deux éléments nutritifs l’azote et le phosphore en interaction avec le phytoplancton et le zooplancton. Le modèle écologique est constitué de deux compartiments, la colonne d’eau et la couche supérieure de sédiment. Huit variables d’états caractérisent la colonne d’eau et six le compartiment sédiment. Comme première application, le modèle a été testé sur la lagune de Bizerte. Une comparaison entre les résultats des simulations et les observations a montré que le modèle a pu reproduire...
Tipo: Journal Contribution
Palavras-chave: .; Dissolved oxygen; Hydrodynamics; Models; Nutrient cycles; Phytoplankton; Zooplankton; Dissolved oxygen; Models; Phytoplankton; Zooplankton; Hydrodynamics; Http://aims.fao.org/aos/agrovoc/c_36106; Http://aims.fao.org/aos/agrovoc/c_4881; Http://aims.fao.org/aos/agrovoc/c_13344; Http://aims.fao.org/aos/agrovoc/c_15490; Http://aims.fao.org/aos/agrovoc/c_3723.
Ano: 2008
URL: http://hdl.handle.net/1834/3694

Hydrodynamic numerical modelling of Maputo Bay
Provedor de dados: 20
Autores: Canhanga, S.J.V.
The aim of this work was to understand by using a numerical model, the main characteristics of the Maputo Bay hydrodynamics; and furthermore to assess the hydrodynamics implications on the different processes that can occur in the Bay. The study was initiated with a description of the hydrodynamical characteristics of Maputo Bay, through the analysis of vertical profiles of salinity and temperature, time series of the components of tide currents and water elevation. The wind intensity and river runoff patterns were also studied. Analysis of temperature and salinity profiles have revealed that the Maputo Bay can be considered vertically homogeneous; however, when floods occur or when there is high intensity of precipitation on summer season, a horizontal...
Tipo: Theses and Dissertations
Palavras-chave: Hydrodynamics; Mathematical models.
Ano: 2003
URL: http://hdl.handle.net/1834/181

Relevancia de procesos costeros en la hidrodinámica del Golfo de Uraba (Caribe colombiano)
Provedor de dados: 20
Autores: Escobar, S.
Se presenta en este artículo una metodología a través de la cual se determina cuantitativamente el efecto en la hidrodinámica del golfo de Urabá de un grupo de procesos costeros y forzamientos externos, los cuales, inicialmente, se asumen relevantes en el comportamiento del flujo. De acuerdo con este propósito, se realiza la simulación numérica del flujo y el oleaje en el golfo a través de la plataforma de modelación Delft3D. La modelación considera los siguientes procesos: (i) la influencia marina a través del forzamiento de la marea en la frontera norte del golfo; (ii) el oleaje; (iii) la estratificación termo-salina; (iv) el arrastre del viento y (v) la influencia fluvial a través de la descarga del río Atrato y otros tributarios secundarios. La...
Tipo: Journal Contribution
Palavras-chave: Beach processes; Spatial analysis; Numerical models; Coasts; Hydrodynamics.
Ano: 2011
URL: http://hdl.handle.net/1834/4510

The physical limnology of Winam Gulf and Rusinga Channel of Lake Victoria during April-May and August of 2005
Provedor de dados: 20
Autores: Alexander, R.; Antenucci, J.P.; Attwater, G.
Winam Gulf (Kenya) is a large (surface area ~ 1400 km2) and shallow (&lt;20 m) bay of northeastern Lake Victoria with only one connection to the open lake through Rusinga Channel. To understand the exchange dynamics between Winam Gulf and the offshore waters of Lake Victoria and the hydrodynamics of the region, field studies were carried out from Apr. 22-May 4 and Aug. 5-16 of 2005. A meteorological station (shortwave, total radiation, air temperature, relative humidity, wind speed and direction), thermistor chain (0.75m vertical resolution) and ADCP (40 cm vertical resolution) were deployed in Rusinga Channel in a depth of 20m. Similarly, at an offshore station in northeastern Lake Victoria another thermistor chain was deployed in a water depth of 40 m...
Tipo: Proceedings Paper
Palavras-chave: Hydrodynamics; Physical limnology; Lake dynamics; Current forces; Physical oceanography; Water circulation; Inland waters; Freshwater lakes; Coupled bodies.
Ano: 2006
URL: http://hdl.handle.net/1834/1463

Modèle couple dynamique -écologie pour la lagune de Bizerte
Provedor de dados: 20
Autores: Bejaoui, B.; Harzallah, A.; Moussa, M.; Chapelle, A.
This work concerns the development of a three dimensional hydroecological model based on two nutrient elements, nitrogen and phosphorus.The hydrodynamic model is 3D forced by monthly climatic data of NOAA. The ecological model was developed based on two nutrient elements, nitrogen and phosphorus in interaction with the phytoplankton and zooplancton. The ecological model is made up with two compartments, the water column and the sediment layer. Eight state variables are used to characterize the water column and six state variables for the sediment layer. As a first application, the model was tested on the Bizerte Lagoon. A comparison between simulations and observations showed that the model can reproduce with satisfactory way the observations carried out...
Tipo: Journal Contribution
Palavras-chave: Dissolved oxygen; Hydrodynamics; Models; Nutrient cycles; Phytoplankton; Zooplankton.
Ano: 2008
URL: http://hdl.handle.net/1834/4264

Estudios de la circulación forzada por el viento en el estuario del Río de la Plata y sus implicancias en la estratificación: resultados del análisis de datos y simulaciones numéricas
Provedor de dados: 20
Autores: Meccia, V.L.
For the first time, the analysis of historical salinity data and new current series is combined with high resolution numerical simulations, with the aim of understanding the processes that occur in the active and important Río de la Plata estuary (South America). With that objective, the first relatively long ADCP current series collected in two points of the estuary are analyzed. Only 25% of the currents variance is accounted by the tide. Approximately another 25% is associated with internal wave activity at the sampling locations, where a strong stratification exists. These waves are forced by land-sea breeze and tide and are very frequent during spring and summer. The remaining 50% of the energy is wind driven and occurs in synoptic to intra-seasonal...
Tipo: Theses and Dissertations
Palavras-chave: Estuaries; Estuarine dynamics; Circulation; Winds; Salt wedges; Hydrodynamics; Estuaries; Winds; Hydrodynamics; Http://aims.fao.org/aos/agrovoc/c_2673; Http://aims.fao.org/aos/agrovoc/c_8401; Http://aims.fao.org/aos/agrovoc/c_3723.
Ano: 2008
URL: http://hdl.handle.net/1834/2830

Limnology of the largest multi-use artificial reservoir in NE Brazil: The Castanhão Reservoir, Ceará State
Provedor de dados: 42
Autores: LACERDA,LUIZ D.; SANTOS,JANAÍNA A.; MARINS,ROZANE V.; SILVA,FRANCISCO A.T.F. DA.
Abstract This work reviews the limnology of the largest multi-use reservoir in NE Brazil, the Castanhão Reservoir in Ceará State, during 5 years of an extended drought when the reservoir’s volume decreased from 88% to about 30%. Major physical and chemical parameters of the water column, phytoplankton community, trophic state and sediment geochemistry were monitored, as well as the impact from extensive aquaculture. Water quality of the full reservoir was maintained due to hydrodynamics, which transport nutrients to the hypolimnion of a stratified water column, rendering an oligotrophic state to the reservoir, notwithstanding the large nutrient inputs from aquaculture and irrigated agriculture. However, with the extension of the drought period, the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hydrochemistry; Hydrodynamics; Nutrients; Water quality; Sediments; Aquaculture.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652018000502073

Bridging molecular and continuous descriptions: the case of dynamics in clays
Provedor de dados: 42
Autores: Dufrêche,Jean-François; Rotenberg,Benjamin; Marry,Virginie; Turq,Pierre.
The theory of transport in porous media such as clays depends on the level of description. On the macroscopic scale,hydrodynamics equations are used. These continuous descriptions are convenient to model the fluid motion in a confined system. Nevertheless, they are valid only if the pores of the material are much larger than the molecular size of the components of the system. Another approach consists in using molecular descriptions. These two methods which correspond to different levels of description are complementary. The link between them can be clarified by using a coarse-graining procedure where the microscopic laws are averaged over fast variables to get the long time macroscopic laws. We present such an approach in the case of clays. Firstly, we...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Clays; Multi-scale modelling; Molecular dynamics; Hydrodynamics; Brownian model.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652010000100006

Influence of mass transfer on bubble plume hydrodynamics
Provedor de dados: 42
Autores: LIMA NETO,IRAN E.; PARENTE,PRISCILA A.B.
ABSTRACT This paper presents an integral model to evaluate the impact of gas transfer on the hydrodynamics of bubble plumes. The model is based on the Gaussian type self-similarity and functional relationships for the entrainment coefficient and factor of momentum amplification due to turbulence. The impact of mass transfer on bubble plume hydrodynamics is investigated considering different bubble sizes, gas flow rates and water depths. The results revealed a relevant impact when fine bubbles are considered, even for moderate water depths. Additionally, model simulations indicate that for weak bubble plumes (i.e., with relatively low flow rates and large depths and slip velocities), both dissolution and turbulence can affect plume hydrodynamics, which...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Aeration; Bubbles; Hydrodynamics; Mass transfer; Modeling; Oxygenation.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652016000100411

Hydrodynamic Aspects at Vitória Bay Mouth, ES
Provedor de dados: 42
Autores: GARONCE,FLÁVIA A.A.; QUARESMA,VALÉRIA S.
Understading the hydrodynamic behavior and suspended particulated matter (SPM) transport are of great importance in port regions such as Vitória Harbor, which is located at Vitória Bay, Vitória – ES, Brazil. Vitória Bay is an estuary that has not been systematically assessed through a temporal analysis in order to identify its hydrodynamics characteristics and SPM exchange. This study aims to investigate salt and suspended particulate matter flux at the estuarine mouth of Vitória Bay by understanding the temporal variation of salinity, temperature and tidal currents within the water column and at the channel crosssection. Results showed that the estuarine mouth tended to present partial stratification periods during neap tides and little stratification in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Estuary; Hydrodynamics; Suspended particulate matter; Vitória Bay.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652014000200555

Seasonal dynamics in the inner Guayas Estuary, Ecuador
Provedor de dados: 50
Autores: Marín Jarrín,María José; Marín Jarrín,José R.; Borbor-Córdova,Mercy J.; Espinoza Celi,Maria Esther; Domínguez-Granda,Luis.
ABSTRACT The Guayas estuary in Ecuador is the largest estuarine ecosystem on the Pacific coast of South America. This estuary provides nursery and fisheries habitats, as well as filtering and detoxification services provided by suspension feeders, vegetation, and wetlands. We used oceanographic and meteorological observations to understand the hydrodynamic variability of two areas in the inner part of the estuary, Manglares de Churute and Estero Salado, from February 2016 to February 2017. Churute has less anthropogenic impacts than Estero Salado, which is currently uncoupled from river flow and highly influenced by Guayaquil, the second largest city in Ecuador, and adjacent shrimp pond effluents. The influences from the ocean and river on Churute include...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hydrodynamics; Mangroves; Estuary; Guayas; Seasonality.
Ano: 2022
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0122-97612022000200129

The influence of hydrodynamics on the spatial and temporal variation of phytoplankton pigments in a large, sub-tropical coastal lake (Brazil)
Provedor de dados: 52
Autores: Cardoso,Luciana de Souza; Marques,David da Motta.
This study evaluated the spatial and temporal distribution of phytoplankton pigments in Itapeva Lake and its relationship with hydrodynamic aspects. Regarding spatial distribution, a decreasing N®S gradient was generally observed for the pigments, except in summer. This inversion observed during the summer was influenced by the predominant fetch (N-E). The horizontal heterogeneity was proved (ANOVA) for all seasons of the year, except spring. Spatially in spring, the vertical variance was much more significant (p&lt;0.05) than the horizontal one. The sampling shifts presented a permanent degree of variability among the seasons of the year, showing the existence of a diurnal cycle in the concentration of chlorophyll a. This behavior was related to the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Pigment; Phytoplankton; Shallow lake; Hydrodynamics; Wind; Bloom.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132004000400013