Consulta: subjectFacets:"Modélisation numérique"
Registros recuperados: 14
Data/hora: 11/06/2024 16:16:10

Impact des fines échelles spatio-temporelles de l'atmosphère sur le couplage entre océan hauturier et plateau continental dans un système d'upwelling de bord est
Provedor de dados: 5
Autores: Desbiolles, Fabien.
This study focuses on the oceanic response to fine atmospheric spatial and temporal scales, and especially fine wind patterns in the Benguela and Canary upwelling systems. These regions are under the influence of local or regional wind, blowing parallel to the coast. The wind is the main driver of the cold-water upwelling and is modulated by several physical processes at various scales. The nature of the interactions with the atmosphere, the ocean and the adjacent continent differs according to these processes. For the past 20 years, outstanding efforts have been made in the description and understanding of the atmospheric conditions at the sea surface. An increasing number of space missions and major technical improvements have allowed refinement of the...
Tipo: Text
Palavras-chave: Système d'upwelling de bord Est; Fines échelles atmosphériques; Interactions air-mer; Profil du vent à la côte; Diffusiométrie; Modélisation numérique; Eastern boundary upwelling system; Atmospheric fine scales; Air-sea interactions; Coastal wind profile; Scatterometry; Numerical model.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00405/51693/52257.pdf

Influence des conditions hydrométéorologiques sur les flux et bilans sédimentaires en estuaire de Seine
Provedor de dados: 5
Autores: Grasso, Florent; Schulz, Elisabeth; Le Hir, Pierre; Verney, Romaric; Thouvenin, Benedicte.
La dynamique sédimentaire à l’embouchure de l’estuaire de Seine est principalement contrôlée par les forçages hydrométéorologiques (débit, vent, vagues, marée) et les fortes pressions anthropiques (endiguement, dragage, clapage). La compréhension et la quantification de la dynamique des flux sédimentaires en suspension (sable/vase) est un enjeu majeur, autant d’un point vu écologique (ex. turbidité, envasement) que financier (ex. gestion des chenaux de navigation). La mise en place de réseaux de mesure in situ permet une meilleure compréhension de la dynamique sédimentaire de l’estuaire, mais leur caractère local rend difficile toute estimation des flux et bilans sédimentaires. Pour répondre à ces questions, cette étude s’appuie sur la modélisation...
Tipo: Text
Palavras-chave: Dynamique hydro-sédimentaire; Sable/vase; Estuaire de Seine; Modélisation numérique; Mesures in situ; Dragage; Flux résiduels et bilans; Année/trimestres.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00348/45928/45621.pdf

Variation of the tidal properties around Gran Canaria
Provedor de dados: 5
Autores: Martinez, A; Perez, E; Bruno, M.
Analysis of water level and current meter series from different locations on the island shelf of Gran Canaria reveals strong variations in tidal properties. Semidiurnal sea level amplitudes agree with the results obtained from global tidal models for this region only on the northern coast of the island, while they decrease towards the southwest (10 cm difference for the M-2 constituent). Semidiurnal currents present maxima at the southeastern and northwestern extremities of the island (30-40 cm s(-1) for M-2) and minima in the north-northeast and southwest (3-6 cm s(-1) for M-2), showing simultaneous strong changes in the phase. Diurnal levels and currents display smaller variations than the semidiurnal band. The behaviour of semidiurnal constituents is...
Tipo: Text
Palavras-chave: Marée; Courant de marée; Île; Modélisation numérique; Îles Canaries; Tide; Tidal current; Island; Numerical modelling; Canary Islands.
Ano: 1999
URL: http://archimer.ifremer.fr/doc/00325/43625/43258.pdf

Modélisation haute-résolution des courants dans le Golfe de Guinée : Etude des oscillations bimensuelles.
Provedor de dados: 5
Autores: Guiavarch, Catherine.
Currentmeter measurements on the continental slope of the Gulf of Guinea (near 7°40 S) point out a biweekly oscillation of the currents, bottom intensified and oriented along the bathymetry. Those energetic oscillations dominate the signal. A three-dimensional high-resolution primitive equation model  (NEMO/OPA) of the Gulf of Guinea has been developed to study the oscillations and their forcing mechanism.  The data does not support the tide as a forcing mechanism and the wind-forced regional model reproduces biweekly oscillations, which fit the data quite well. Experiments with different forcings have been run to explore the origin of the biweekly variability. Those experiments highlight the equatorial origin of the oscillations forced by equatorial...
Tipo: Text
Palavras-chave: Deep current; Biweekly oscillations; Equatorial waves; Coastal trapped waves; Gulf of Guinea; Numerical modelling; Courant profond; Oscillations bimensuelles; Ondes équatoriales; Ondes piégées à la côte; Golfe de Guinée; Modélisation numérique.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/these-3647.pdf

Dynamique sédimentaire multiclasse : de l’étude des processus à la modélisation en Manche
Provedor de dados: 5
Autores: Blanpain, Olivier.
The purpose of this work is the implementation of a sediment transport model in the English Channel. The design of such a model requires the identification of the physical processes, their modelling and their in-situ validation. Because of the sedimentary particularities of the study area, modelling of the mechanical behaviour of a non uniform mixture of sediments and particularly of the fine grains within a coarse matrix is required. This study focused on the characterization of the relevant processes by acquisition of experimental and in-situ data. Data acquired in hydro-sedimentary conditions comparable to those found in the English Channel are scarce. A new instrument and image processing technique were specifically conceived and implemented in-situ to...
Tipo: Text
Palavras-chave: Manche; Sédiment multiclasse; Modélisation numérique; Morphodynamique; Charriage; Tri sédimentaire; Mesures in-situ; Traitement d’images; Mesures en canal; English Channel; Graded sediment; Numerical modelling; Morphodynamics; Bedload; Sediment sorting; In-situ data; Image processing; Flume experiments.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00003/11426/7962.pdf

Oceanic response to atmospheric forcing derived from different climatic data sets. Intercomparison study for the Black Sea
Provedor de dados: 5
Autores: Staneva, Jv; Stanev, Ev.
Available climatic and atmospheric analysis data have been used to prepare forcing functions for the Black Sea numerical model, based on the Bryan-Semtner-Cox Modular Ocean Model and including parameterizations for the atmosphere-ocean exchange, inflow through the strait of Bosphorus and the Mediterranean plume. Atmospheric data from different sources are compared and the drawbacks of some of them illustrated. A new wind stress data set, based on ship observations, is prepared. Compared to the existing wind stress estimates, the present ones use additional data and more accurate parameterization of the boundary layer physics. The intercomparison between forcing data sets is focused on the heat flux and freshwater flux at the sea surface. The model...
Tipo: Text
Palavras-chave: Mer Noire; Échange d'eau; Échange de chaleur; Tension du vent; Modélisation numérique; Black Sea; Water exchange; Heat exchange; Wind stress; Numerical modelling.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00325/43664/43206.pdf

Observation et modélisation des propriétés directionnelles des ondes de gravité courtes
Provedor de dados: 5
Autores: Peureux, Charles.
Short surface gravity waves are ubiquitous at the ocean surface, with lengths from a few tens of meters to a meter typically.Knowing their propagation directions at sea is important in several respects, especially for the understanding of sea-state dynamics, airsea interactions and particles surface drift.Their directional distributions are here investigated in the light of the recent progress made in instrumentation techniques. The analysis of ocean bottom seismo-acoustic noise records allows for the extraction of a quasi-universal behavior which indirectly depends on this distribution through the socalled overlap integral. It is coherent with direct observations of the wave field obtained from tri-dimensional reconstructions of the ocean surface...
Tipo: Text
Palavras-chave: Vagues courtes; Bruit sismoacoustique; Modélisation numérique; Intégrale de recouvrement; Bimodalité; Short ocean surface waves; Seismoacoustic noise; Stereo-video; Numerical modelling; Overlap integral; Bimodality.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00498/60970/64378.pdf

Caractérisation expérimentale et numérique du comportement hydrodynamique d’une hydrolienne à membrane ondulante
Provedor de dados: 5
Autores: Trasch, Martin.
The thesis presented in this document deals with the caracterisation of the behaviour of an undulating membrane tidal energy converter. This kind of device uses the flutter instabilities occurring between a semi-rigid pre-strained membrane and a fluid flow in order to convert the sea currents energy. Above a certain critical flow speed, the structure ondulates, thus activating the linear converters fixed on it. In order to study this system, an experimental model is developped and tested in a flume tank. The power conversion system is simulated by hydraulic dampers. The membrane’s dynamics is analysed in many configurations through trajectory and force measurements, and leads to a parametric study. More realistic flow conditions are also studied, such as...
Tipo: Text
Palavras-chave: Énergies marines renouvelables; Hydrolienne; Interaction fluidestructure; Instabilité de flottement; Essais expérimentaux; Particle Image Velocimetry; Modélisation numérique; Méthode vortex; Éléments finis; Corotationnel; Houle; Effet d’échelle; Marine renewable energy; Tidal energy converter; Power takeoff; Fluid-structure interaction; Flutter instability; Experimental trial; Particle Image Velocimetry; Numerical model; Vortex method; Corotational finite elements; Surface wave; Scale effect.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00490/60185/63527.pdf

Data assimilation in a marine ecosystem model of the Ligurian Sea.
Provedor de dados: 5
Autores: Magri Hoeltzener, Stephanie; Brasseur, Pierre; Lacroix, Geneviève.
The objective is to explore the potentialities of sequential statistical estimation methods to assimilate observations in a primary production biological model coupled to a vertical 1D hydrodynamical model characterised by a k-l turbulent closure. The assimilation method is derived from the SEEK filter (Singular Evolutive Extended Kalman filter), which uses an error subspace represented by multivariate empirical orthogonal functions (EOFs). Real data assimilation experiments collected at sea have been realised to reconstruct the variability of the Ligurian Sea ecosystem during the FRONTAL field experiment.
Tipo: Text
Palavras-chave: Ligurian Sea; Kalman filter; Data assimilation; Numeric modelling; Physical/biogeochemical model; Mer Ligure; Filtre de Kalman; Assimilation de données; Modélisation numérique; Océanographie physique/biogéochimique.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-687.pdf

3D modelling in the Sado estuary using a new generic vertical discretization approach
Provedor de dados: 5
Autores: Martins, F; Leitao, P; Silva, A; Neves, R.
Sado estuary (Portugal) is a mesotidal well-mixed estuary. The flow however, displays strong three-dimensional features associated with bathymetry variations. The flow is simulated using a three-dimensional primitive equation model based on the finite-volume method and incorporating a new concept for the vertical discretization. The innovative features of the model are analysed and the advantages of the finite-volume method to implement the generic vertical discretization are put into evidence. The model was validated using water level, velocity and salinity measurements in several stations along the estuary. Results show the influence of main channel's strong curvature on the generation of secondary flows inside the estuary. The steep bathymetry of the...
Tipo: Text
Palavras-chave: Estuaires; Modélisation numérique; Écoulements secondaires; Recirculation verticale; Discrétisation verticale générique; Estuaries; Numerical modelling; Secondary flows; Vertical recirculation; Generic vertical discretization.
Ano: 2001
URL: http://archimer.ifremer.fr/doc/00291/40270/38641.pdf

Influence des ondes d'inertie-gravité sur la dynamique tourbillonnaire
Provedor de dados: 5
Autores: Louazel, Stephanie.
The purpose of this thesis is to study the influence of inertia-gravity waves on eddies dynamics, this process being part of the interaction between slow and fast dynamics of oceanic flows. Eddies dynamics is indeed slow but it is also intermediate between the fast inertia-gravity waves dynamics and the very low frequency dynamics of general circulation. The first part reviews the literature on this interaction. Then two numerical studies are performed. The first one concerns the influence of inertia-gravity waves on the filamentation diagnostic of an elliptic vortex. In presence of inertia-gravity waves this filamentation process is found to be slightly altered. However, the information required to analyze the filamentation process is shown to be entirely...
Tipo: Text
Palavras-chave: Numerical experiment; Filamentation; Waves / vortex interaction; Modélisation numérique; Filamentation; Interaction ondes / tourbillons.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2004/these-539.pdf

Projet EMACOP : modélisation numérique des vagues à l'approche de la digue d'Esquibien par le code SWASH
Provedor de dados: 5
Autores: Coignard, Jonathan; Michard, Bertrand; Filipot, Jean-francois; Sergent, Philippe.
Dans un contexte de développement durable, la tendance actuelle est de se tourner vers des sources alternatives de production d’énergie. Le projet National de Recherche EMACOP (Energies MArines COtières et Portuaires) a entre autres pour objectif de définir le potentiel houlomoteur aux abords d’ouvrages côtiers. Dans le présent travail, une simulation numérique des transformations induites aux vagues à l’approche du site d’Esquibien (Finistère) est réalisée. La modélisation numérique des vagues est effectuée avec le code de calcul SWASH (ZIJLEMA et al., 2011). Pour chaque simulation, des résultats d’élévation temporelle, de hauteur significative et de spectre directionnel sont obtenus. Les analyses des simulations portent sur l’étude des conditions...
Tipo: Text
Palavras-chave: EMACOP; Energies marine; Modélisation numérique; Transformation des vagues; Code SWASH; Site; Esquibien; Potentiel énergétique; Génie côtier.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00233/34429/32852.pdf

Prévision opérationnelle des niveaux de la mer, surcotes et décotes sur les côtes de la Manche et de l’Atlantique
Provedor de dados: 5
Autores: Pineau-guillou, Lucia; Theetten, Sebastien; Dumas, Franck; Lecornu, Fabrice; Idier, Deborah.
Le système pré-opérationnel PREVIMER fournit des observations et des prévisions côtières sur les trois façades métropolitaines Manche, Atlantique et Méditerranée. Il fournit en particulier les prévisions de courants, niveaux de la mer, surcotes et décotes et vagues. L’objectif de l’étude est de mettre en place un système de modélisation des ondes longues (2DH) haute résolution (une centaine de mètres) sur l’ensemble des côtes métropolitaines. Les expériences menées dans le cadre de PREVIMER ont mis en évidence l’importance d’une meilleure prise en compte de l’action du vent et des vagues - par l’amélioration de la paramétrisation du coefficient de traînée en surface - et du wave set-up. Ainsi, ces modèles à haute-résolution intègrent ces dernières...
Tipo: Text
Palavras-chave: Hydrodynamique côtière; Modélisation numérique; Wave set; Coefficient de traînée; Surcotes; Niveau de la mer; Système opérationnel.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00157/26802/24913.pdf

Modélisation de la dispersion du phosphogypse dans le golfe de Gabès
Provedor de dados: 20
Autores: Bejaoui, B.; Raïs, S.; Koutitonsky, V.
This work concerns the modeling of the phosphogypsum dispersion emitted by the chemical industries in the gulf of Gabès. The CORMIX model based on the dimensional analysis theory is used for this study. An analysis of the sensitivity of the model parameters was initially made; eight simulations were then carried out to determine the space extent of pollution on the level of the gulf. For each condition of tide, we carried out four simulations, two concerns the high tide and two concerns the low tide. Simulations showed that pollution by phosphogypsum is spread out in space over a surface of about 60 km2.
Tipo: Journal Contribution
Palavras-chave: Numerical modeling; Modélisation numérique; Gabès; Dispersion; CORMIX; Phosphogypse; Phosphogypsum; Golfe de Gabès Dispersion Chemical pollutants MED  Tunisia  Gabes Gulf Marine pollution Mathematical models Mathematical models http://aims.fao.org/aos/agrovoc/c_24199.
Ano: 2004
URL: http://hdl.handle.net/1834/1555