Tesis sobre el tema "Approche "Hydrodynamique""
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Josserand, Jacques y Antoine Alemany. "Modélisation des processus de l'électrodéposition continue : approche couplée hydrodynamique et électrochimique". Grenoble INPG, 1994. http://www.theses.fr/1994INPG0031.
Texto completoZhang, Shuheng. "Approche microfluidique polyvalente de la cristallisation". Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4056/document.
Texto completoCrystallization is influenced by several parameters such as supersaturation, temperature, environment, and hydrodynamics. Thus, a rapid screening of crystallization conditions is often required during the study of the crystallization of a molecule. But when a small amount of material is available, a suitable experimental tool is essential. In our case, the microfluidic system dedicated to crystallization is based on the generation of nanoliter droplets in which crystallization can occur independently. Forming hundreds of droplets with monodisperse sizes and experimental conditions, we can make a large number of experiments per condition for statistical studies to meet the stochasticity of the phenomenon of nucleation while consuming little material. Our goal is to create a universal microfluidic assembly which is compatible with all solvents and molecules. Thus, we are interested in simple microfluidic junctions and tubings which is resistant to many solvents. From such systems, we have first characterized the hydrodynamic properties of the set-up: we sought to control microfluidic flow and reduce the volumes put-in. We studied the droplet generation regimes and the scaling law of drop size and frequency. For crystallization study of biomolecule, we have validated our microfluidic set-up for crystallization studies in a viscous media, on the recombinant urate oxidase or the rasburicase in an aqueous solution of PEG. Finally, we integrated a module for on-line characterization of each droplet’s chemical composition
Pham, Hoang Lam. "Fonctionnement des biofiltres : approche numérique de certains couplages hydrodynamique/bioflms et modélisation". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI073/document.
Texto completoSolute transport coupled with biofilm growth in porous media is encountered in many engineered applications, for instance biofiltration of wastewater and air pollutant treatment. In terms of modelling, the interaction between biology, hydrodynamic and chemistry are still difficult to understand at the fine scale: that led to a wide dissemination of macroscopic model, simpler to handle. However, one issue consists in providing a macroscopic model complex enough to take into account the relevant processes accounting for the coupling between the biomass development and system functioning, but simple enough for operational use. This thesis focused on few selected processes that influence the macroscopic behavior of such system. First, we investigated the permeability reduction modeling accounting for biofilm development. A model including two features that result in permeability reduction (pore radius reduction and pore plugging) was developed. This model was assessed in a wide range of experimental data. Another part of the thesis focused on the initial biomass attachment that is an important feature to characterize the system initial state. Following the concept that bacterial cell can be treated as soft colloids, a new correlation equation was developed to estimate the bacteria attachment efficiency. This correlation is based on the regression analysis of a wide range of experimental data of colloid deposition in various electrolyte conditions, flowrates and geometries of porous media. New dimensionless parameters have been introduced to represent the coupled effects of Derjaguin-Landau-Verwey-Overbeek (DLVO) forces, hydrodynamic forces and to account for geometry of porous media. These features were introduced in a 1D dimensional model that have been developed for the numerical simulation of solute transport coupled with biofilm growth. An important issue in this model was to properly represent biofilm detachment. Another distinctive feature of our model is an attempt to account for the “sloughing” process in modeling biofilm detachment. Sloughing is a different process than erosion which corresponds to a discrete removal of large fraction of biofilm. In this study, biofilm sloughing has been separately accounted in the numerical modeling porous media bioclogging. Biofilm sloughing was considered as a stochastic process and quantified by random generator. So this discrete events could be incorporated into other continuous processes to determine the biomass transfer from biofilm to the liquid phase. Numerical simulations have been performed using OpenFoam to implement the model. Simulation with and without the sloughing term were performed and discussed in the frame of available literature data
Lehmann, François. "Hydrodynamique en milieux poreux heterogenes non satures : identification des parametres par approche inverse". Université Louis Pasteur (Strasbourg) (1971-2008), 1996. http://www.theses.fr/1996STR13225.
Texto completoAbsi, Joseph. "Les paliers à rainures : approche expérimentale et simulation numérique". Poitiers, 1994. http://www.theses.fr/1994POIT2273.
Texto completoLafon, Philippe. "Mélange laminaire de fluides miscibles en cuve agitée : approche numérique". Toulouse, INPT, 1989. http://www.theses.fr/1989INPT021G.
Texto completoChastel, Thibault. "Interactions hydrodynamiques entre une sphère et une paroi texturée : approche, collision et rebond". Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066509/document.
Texto completoWe investigate experimentally the dynamics of a sphere near a textured wall in a viscous fluid. High frequency laser interferometry is used to measure small displacements of the sphere. The texture is comprised of arrays of micro-pillars, whose geometrical parameters are systematically varied in order to study their influence of the dynamics of approach, collision and rebound of the sphere. Under creeping flow conditions, the sphere velocity near the textured wall is increased compared to the case of a smooth wall, as a result of the modification of the lubrication force due to the texture. We describe this modification using several hydrodynamic models. An effective slip length over the pillar array is measured. At moderate Stokes number the sphere inertia is non-negligible and the sphere can either stick or bounce off the wall. The sticking dynamics exhibit several regimes which can be described by taking into account the modification of the lubrication force by the texture. The micro-pillars modify the critical Stokes number for the bouncing transition. The micro-rebounds are characterized. Finally, the contact dynamics between the sphere and the pillars are described by a Hertz law modified by the texture geometry
Sagnes, Pierre. "Morphométrie, potentiel hydrodynamique et utilisation de l'habitat lotique par les poissons : une nouvelle approche écomorphologique". Lyon 1, 1998. http://www.theses.fr/1998LYO10023.
Texto completoAngulo-Jaramillo, Rafael. "Caractérisation hydrodynamique de sols déformables partiellement saturés : étude expérimentale à l'aide de la spectrométrie gamma double-sources". Phd thesis, Grenoble INPG, 1989. http://tel.archives-ouvertes.fr/tel-00688064.
Texto completoMesbahi, Amine. "Effets hydrodynamiques dans un réacteur à plasma de croissance de diamant : approche numérique et expérimentale". Paris 13, 2013. http://scbd-sto.univ-paris13.fr/secure/edgalilee_th_2013_mesbahi.pdf.
Texto completoIn moderate pressure/low flow-rate diamond deposition plasma modeling, hydrodynamics effects are not taken into account. As a matter of fact, under these conditions, transport of the reactive species is mainly controlled by diffusion. However, when working at very high power density (high pressure and microwave power) and flow rates higher than 500 sccm, growth rate has been seen to be a function of the gas inlet and outlet set-up. In the context of this PhD, we have developed both a 2D axi-symmetrical and a full 3D models able to describe the hydrodynamic flow in PECVD (Enhanced Chemical Vapor Deposition) diamond reactors. Due to the complexity for developing a complete plasma model, we have strongly simplified the plasma description. On the one hand, a thermal source term able to simulate the plasma gas temperature spatial distribution has been defined, and on the other hand, the chemical kinetics scheme has been somewhat reduced. Comparisons between the results obtained by this new model with those provided by LSPM’s existing plasma models and the experimental results allowed us to validate our approach. The model correctly reproduces the thermochemical processes behavior. On this basis, new configurations for the gas inlet and outlet set-up using 3D simulations were conducted. Some were seen to be relevant for improving the diamond deposition process
Artigue, Lise. "Cycles biogéochimiques océaniques : apports des traceurs élémentaires et isotopiques, l'aluminium et le fer couplés à une approche hydrodynamique". Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30214.
Texto completoThe overall objective of this thesis is to further our understanding of ocean biogeochemical cycles (sources, internal cycles, sinks) using tracers present in seawater (the concentration of dissolved aluminium and the isotopic composition of dissolved iron) combined with hydrodynamic tools. Aluminum is used as a tracer from lithogenic sources to the ocean, while iron isotopes tell us about the iron cycle in the ocean. This thesis focuses first on the analysis of water masses of the 22ºN longitudinal section in the North Atlantic carried out in the framework of the GEOTRACES GApr08 campaign. This study combines for the first time an extended optimum multiparameter analysis (eOMPA) of water masses with an estimation of their Lagrangian trajectories from a hydrodynamic model. In addition, the dissolved aluminium (dAl) measurements carried out have made it possible to produce a first section of dAl at 22ºN and these same tools have enabled an advanced analysis. The joint use of the 1D model of surface dust advection-deposition and the eOMPA results highlighted the predominant processes associated with the measured dAl concentrations. (i) At the surface, both advection and deposition of atmospheric dust are essential to explain the observed dAl concentrations, although in the west, an additional external source is required. This source could come either from the Amazon River or from erosion in the Petites Antilles. (ii) Between 200 and 800m, in an area of strong atmospheric deposition (below the Saharan plume), high dAl concentrations result from oceanic transport. The net balance of dissolved-particle interactions, however, is a subtraction of dAl, probably by adsorption onto particles. (iii) Below 800 m, the effect of dissolved-particle interactions is reversed and reversible scavenging results in a net source of dAl. (iv) Below 3340 m, the Snakepit hydrothermal source is found to be a significant local source of dAl. Unlike aluminium, iron (Fe) is an essential micronutrient for primary production. This micronutrient limits the primary production in 30-40% of the ocean. In the framework of the GEOTRACES KEOPS 1 and 2 campaigns, the Fe isotope measurements presented in this thesis allow the study of micronutrient sources in a naturally fertilized area of the Southern Ocean, the Kerguelen Islands. Our Fe isotope measurements reveal several elements on its cycle. (i) In the absence of external input, the Fe isotope signatures of water masses are preserved over 4500 kilometers, which allows us to use this tracer to follow the origin of Fe in the ocean. (ii) A reducing sedimentary source of dissolved Fe from the Kerguelen Island margin feeds primary production downstream. (iii) A local non-reducing sedimentary source of dissolved Fe impacts the bottom waters of the Kerguelen Plateau stations, but does not appear to contribute significantly to the shallower waters. This result is identified for the first time directly in an HNLC region. This PhD work highlights the key importance of 1) taking into account horizontal transport, if possible quantitatively, in the interpretation of trace element and isotope distributions, and 2) the interactions of dissolved particles, in particular the so-called reversible scavenging process (adsorption-desorption), on the cycles of trace elements and isotopes
Manciati, Carla J. "Modélisation de l'interaction surface – souterrain du système aquifère Tumbaco - Cumbayá en Equateur, avec une approche hydrodynamique et géochimique". Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20086/document.
Texto completoThe Tumbaco – Cumbayá aquifer is found in the context of volcano-sedimentary aquifers. This aquifer is located in the Interandean Valley, 15 km to the east of Quito. The principal aquifer is the volcano-sedimentary formation Chiche. It is limited by the Chiche and San Pedro rivers, the Quito fault and the Pasochoa volcano. The Ilaló volcano is in the middle of the study zone and constitutes a second essentially volcanic aquifer, and is therefore subject to geothermal influences. This volcanic formation appears to be below the Chiche formation. The geologic layer on the surface is called Cangahua, it covers the entire zone and is impermeable. The exploitation of the Chiche and Ilaló aquifers was theoretically suspended in 2006, when arsenic concentrations > the WHO standard of 10 microg/l were found. Our objective is to improve the knowledge of the functioning of this aquifer system using three main research methods: i) hydrodynamics, ii) geochemistry and iii) stable isotopes, 18O - 2H, and radioactive isotopes, 3H - 14C.Hydrodynamics showed that the aquifer system has a low seasonality. We revealed that the aquifers are currently exploited for industrial and domestic uses, contrary to what was known at the beginning. The Ilaló volcano divides the south and north parts of the Chiche aquifer, with the volcano apparently acting as a hydraulic barrier for flows. The Chiche and San Pedro rivers are the drainage axes of the Chiche aquifer in the north and south.The analyses of the waters' physical parameters differentiated the two aquifers, Chiche aquifer having lower EC and temperature than the Ilaló aquifer. Major ions analysis revealed waters that vary between Mg-HCO3 pole and a Na-HCO3 pole in both the Chiche and Ilaló aquifers. As concentrations are higher in the Ilaló aquifer than in the Chiche aquifer. In the Chiche aquifer, As concentrations also decrease as the distance from the volcano increases. Arsenic is of natural origin, but no significant correlations were found for the Chiche aquifer. In the Ilaló aquifer a 57% correlation with Fe was found, which suggests an interaction between As and Fe oxides present in the geologic formation.Radioactive isotope 3H was not detected in groundwater from either aquifer, except in one spring in the north of the study area in the Chiche formation. The likely infiltration from recent waters was confirmed by 14C analysis this spring, which showed concentrations > 100 pmc. Other sampling points in the Chiche aquifer have 14C activities between 45.4 - 87.4 pmc. The Ilaló aquifer has 14C activities < 20 pmc. Water ages were calculated and corrected using 13C, which reveal a contamination from geogenic CO2, making water seem older than it is in reality. Despite the age correction, groundwater ages remain very old: Chiche groundwaters are between 400 - 4,000 years old and Ilaló groundwaters are between 11,000 - 44,000 years old. Stable isotopes were used to identify recharge areas. Groundwaters from Chiche aquifer show an isotopic 18O and 2H signature below the Local Meteoric Water Line (slope=3.5). This was interpreted as isotopic fractionation from hot rock and water interactions, which was not observed in the Ilaló aquifer. Recharge altitude calculations show that the Chiche aquifer is fed on the Ilaló and Pasochoa volcano piedmonts, if we consider that climatic conditions over the recharge period are close to current conditions. However, for the Ilaló aquifer, recharge areas appear to be located on the flanks of the volcano, assuming colder recharge climatic conditions than today. This recharge area should no longer be functional because of the Cangahua deposits during the last volcanic events.Results suggest that Ilaló groundwaters are being mixed with Chiche groundwaters. This research is the first to have been done with this level of detail in Ecuador on this type of aquifer and will provide new opportunities for projects in others volcano-sedimentary aquifers in the country
Fuentes-Ruiz, Carlos. "Approche fractale des transferts hydriques dans les sols non-saturés". Grenoble 1, 1992. http://www.theses.fr/1992GRE10147.
Texto completoBeydoun, Hussein. "Estimation de paramètres en milieux poreux non saturés en eau : Approche expérimentale et modélisation". Université Louis Pasteur (Strasbourg) (1971-2008), 2005. http://www.theses.fr/2005STR13047.
Texto completoUnsaturated water flow in porous media is classically modelled by Richards equation. Solving this equation requires the expression of the water content and of the hydraulic conductivity with respect to capillary pressure. These expression depend on the intrinsic hydraulic parameters of the porous medium. Some of these parameters are physically measurable whereas some others need indirect evaluation. The objective of this work is to identify all the hydraulic parameters (of a sand) using inverse modeling of a drainage experiment performed on a laboratory column. This identification is carried out for homogeneous and heterogeneous medium. To this end, experimental device and protocol are developed to depict the drainage system and to improve both the resolution of the hydrodynamic problem (Richards equation) and the inverse procedure (Marquardt algorithm). The aim is also to evaluate uncertainty on parameters and model sensitivity as regard measured observations
Fahs, Hassane. "Identification des paramètres par approche inverse pour la simulation de l'hydrodynamique en milieux fracturés". Strasbourg, 2010. https://publication-theses.unistra.fr/public/theses_doctorat/2010/FAHS_Hassane_2010.pdf.
Texto completoIn this work a robust numerical model is developed for identification of parameters for the simulation of hydrodynamics in fractured media. The first part of this work is devoted to the direct problem that is solved with the Mixed Hybrids Finite Element method (MHFE) and with the technique of mass lumping. The MHFE method reduces the problem to solving a linear system whose associated matrix is symmetric defined positive and mass lumping technique allows avoiding non-physical oscillations. The second part of this work is devoted to solve the inverse problem which is the minimization of an objective function defined by the difference between observations measured and calculated by the direct problem. The minimization problem is solved with the algorithm of Marquardt-Levenberg. This algorithm requires computing the gradient of the objective function which is ensured by the sensitivity method. The third part of this work concerns the parameterization which is the minimization of the number of parameters to be estimated. Because of its simplicity, we focus here on the parameterization by the method of zonation which is to subdivide the area studied in several areas considered homogeneous. Thus, identification of boundaries between zones is done with the technical of refinement indicators. Finally, the numerical model is validated on some numerical test cases and a real test case (the Hydrogeological Experimental Site "HES" of Poitiers
Toutain, Jean. "Approche maxwell-stefan couplée à un modèle de population de gouttes pour la simulation dynamique d'une colonne pulsée d'extraction liquide-liquide". Toulouse, INPT, 1998. http://www.theses.fr/1998INPT023G.
Texto completoDouez, Olivier. "Réponse d'un système aquifère multicouche aux variations paléoclimatiques et aux sollicitations anthropiques - Approche par modélisation couplée hydrodynamique, thermique et géochimique". Phd thesis, Université Michel de Montaigne - Bordeaux III, 2007. http://tel.archives-ouvertes.fr/tel-00198733.
Texto completoL'interprétation des données isotopiques et géochimiques a montré que seuls des transferts verticaux en complément ou non à un écoulement horizontal étaient à même d'expliquer les résultats des analyses et a permis d'exposer l'idée d'une phase de recharge importante à la fin du Pléistocène. La reconstitution du paléoclimat local a été entreprise afin de proposer un scénario des périodes potentielles de recharge du système aquifère sud-aquitain sur les 40000 dernières années. L'ensemble de ces résultats a révélé l'instabilité des conditions d'alimentation de ce multicouche et donc son état transitoire.
Une analyse majeure des caractéristiques géologiques, hydrogéologiques et géothermiques a été engagée et les données mises en cohérence afin de proposer un modèle couplé hydrodynamique et thermique 3D permettant d'étudier l'évolution récente mais également de longue durée. Comportant onze couches, l'extension du modèle est d'environ 32000 km². L'ajustement dans le modèle des données de température a été réalisé. Le calage en transitoire court d'exploitation avec les prélèvements et l'activité de deux stockages de gaz a été effectué. La simulation des variations eustatiques sur les derniers 100000 ans a montré la faible influence de celles-ci sur la nappe des Sables Infra-Molassiques. La simulation des variations de recharge liées aux fluctuations paléoclimatiques sur 40000 ans, objectif final de ce travail, a été exécutée et a permis d'établir trois principaux axes d'écoulement en cohérence avec les contraintes géochimiques. L'importance des transferts verticaux et horizontaux a pu être approchée à l'aide de bilans de flux. Enfin, la baisse piézométrique actuellement observée serait la conséquence des prélèvements de ces trente dernières années et, dans une moindre mesure, de la vidange naturelle du système amorcé il y a 150 ans, suite à une recharge importante au cours du Petit Âge Glaciaire.
Ce travail a mis en exergue l'existence d'échanges entre les différentes couches (aquifères et formations peu perméables), la recharge par drainance verticale importante dans certains secteurs ainsi que le régime transitoire sur plusieurs centaines voire milliers d'années avec un caractère continu. Au final, la compréhension de ce type de multicouche d'extension régionale nécessite de se détacher de la vision commune d'un fonctionnement qui n'aurait débuté qu'avec l'exploitation anthropique sur un système hydrodynamiquement stabilisé.
Anongba, Braphond. "Identification du système hydrogéologique des formations quaternaires et callovo-oxfordiennes du Marais poitevin par approche couplée minéralogique, hydrodynamique et géochimique". Poitiers, 2007. http://www.theses.fr/2007POIT2320.
Texto completoPoitevin marsh is an example of human influence on wetlands. Before getting solutions to safeguard this territory, we had to study hydrological interactions between Poitevin marsh and its underlying aquifers. In this outlook, multivariate approaches are used. On the one hand, sediments of two aquifers are analysed by granulometry and mineralogy, and on the other hand water is analysed by classical and isotopic geochemistry. The granulometrical and mineralogical characteristics show that sedimentary textures of the Poitevin marsh are very heterogeneous. The presence of clays, silts and sands are evidenced in various proportions with permeability range from 10-6 m/s in silty-clay deposits to 10-4 m/s in sand deposits. The isotopic characteristics suggest that Poitevin marsh groundwaters are current at the East of the basin and sub-current and sometimes old (> 2500 years BP) at the West. The confined Oxfordian groundwaters are old (> 7000 years BP). This study shows that exchanges exist in the marsh between the Quaternary and the Jurassic carbonated aquifer. However, these exchanges are limited and preferentially occur on the edge of the marsh. Indeed, the geochemical signature of the confined Oxfordian groundwaters is more chemically marked by the seawater than those of the Quaternary
Thomazo, Jean-Baptiste. "Perception de la texture en bouche : une approche biomimétique". Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS388.
Texto completoThe tongue-palate system is able to detect fine texture variations in the mouth where the best rheometers are essentially blind. One hypothesis to explain this remarkable sensitivity is the presence of myriads of filiform papillae on the surface of the tongue and mechanoreceptors at their base. During this thesis, we developed a biomimetic approach reproducing the functioning of the oral cavity. The tongue is an elastomer block decorated with elongated cylinders assimilated to filiform papillae. It is placed on the bottom of the cell of a rheoscope, a combination of a rheometer and a microscope. The rotating rheometer tool plays the role of the rigid palate, and imposes the flow of the tested liquid. We have imaged while shearing simple fluids the deflection of a papilla and showed that it is proportional to the viscous stresses, in perfect agreement with a recent elastohydrodynamics model. We probed the deflection of a papilla in the presence of granular suspensions as models of food emulsions. We have shown that the presence of particles in the continuous phase slightly modifies the average deformation of a papilla, but strongly changes the standard deviation around this deformation, mainly because of particle/papilla collisions. Finally, we studied the effect of papillae interactions by varying their surface density. This deflection decreases with density. A phenomenological model that treats the papillae as an effective porous medium successfully describes our data across the entire density range
Fraisse, Stéphane. "Structure de la communauté phytoplanctonique des fleuves côtiers en réponse aux contraintes hydrodynamique : une approche basée sur les traits morpho-fonctionnels". Phd thesis, Université Rennes 1, 2013. http://tel.archives-ouvertes.fr/tel-00911634.
Texto completoDarbani, Mohsen. "Approche sans maillage basée sur la Méthode des Eléments Naturels (NEM), pour les écoulements bidimensionnels à surface libre". Compiègne, 2009. http://www.theses.fr/2009COMP1851.
Texto completoSolving equation with free surface often encounters numerical difficulties related to excessive mesh distortion as is the case of dambreak or breaking waves. In this work we explore the meshfree technique based on the Natural Element Method(NEM) to simulate the 2D fluid flow in presence of strong gradients. The equations considered here are those of Saint-Venant shallow water where we consider the full non-linear equations, with a transient flow under the Coriolis effect. The nonlinear terms are computed by using a Lagrangian technique based on the method of the characteristics. This will allow us to avoid setting up a numerical algorithm, like Newton-Raphson’s, which tend to extend the computing time. However, the management of boundary conditions remains a major difficulty in meshless methods. We have therefore defined a thin geometrical domain close to the boundaries and a domain for computing that will be submitted to nodal enrichment, when the particles leave the computational domain
Taïar, Redha. "Vers une nouvelle approche de modélisation de la performance en papillon : évaluation de la résistance à l'avancement au cours du cycle". Lyon 1, 2000. http://www.theses.fr/2000LYO10021.
Texto completoGarcia, Cortes Daniel Ajax. "Contribution à l'étude de l'hydrodynamique et du transfert de masse en réacteurs de type cuve agitée par une approche globale et locale en système gas-liquide". Toulouse, INPT, 2003. http://www.theses.fr/2003INPT030G.
Texto completoMbaye, Serigne. "Couplage hydrodynamique-biomasse dans les procédés de dépollution. Approche locale des mécanismes de croissance et d'adhésion/détachement de micro-organismes sur substrats solides". Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00769936.
Texto completoGouin, Jérôme. "Etude du comportement hydrodynamique des terrains carbonatés karstifiés lors d'un essai par pompage, à partir de 100 cas réels approche comparative et statistique /". Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37605533x.
Texto completoBonnieux, Marc. "Etude du procédé "lit bactérien à ruissellement". Approche hydrodynamique du réacteur et capacité d'élimination des diverses fractions organiques. Application au traitement d'eau usée urbaine". Montpellier 2, 1999. http://www.theses.fr/1999MON20116.
Texto completoEpelbaum, Thomas. "approche de l'équilibre dans les collisions hadroniques à haute énergie". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2014. http://tel.archives-ouvertes.fr/tel-01010346.
Texto completoSaury, Eléonore. "Turbulence et instabilité thermique du milieu interstellaire atomique neutre : une approche numérique". Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00784196.
Texto completoBarthelemy, Kévin. "Adsorption des anions phosphate par des composés ferriques en vue du traitement des eaux usées : approche en réacteur homogène et en mode hydrodynamique contrôlé". Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0237.
Texto completoThe Ph.D. work, presented in this manuscript, is devoted to evaluating phosphate adsorption process on carbonate ferric green rust and ferrihydrite. The main objective concerns an application for the treatment of waste water in rural areas. Both iron oxides are first synthesized and their physico-chemical properties characterized. The ferric green rust structural properties differences as a function of synthesis parameters such as aging period and addition of hydrogen peroxide solution is of particular interest. A detailed study of surface physico-chemical properties by X Photoelectron Spectroscopy is carried out in the case of ferrihydrite. The reactivity of these two iron oxides is then evaluated in batch experiments. Adsorption process follows the pseudo-second order kinetic equation and Freundlich isotherm model which give the best adjustments of experimental data. The influence of various parameters such as pH, ionic strength, etc on phosphate adsorption is also taken into account. Column experiments are afterwards carried out by using filtration material constituted of iron oxide deposited onto pozzolana. The optimal conditions to prepare this filtration material are naturally predetermined. Phosphate adsorption in hydrodynamic mode is characterized by advective and diffusive mechanisms and water regionalization which govern the adsorption process in the column. Moreover, phosphate adsorption capacity and flow rate influence on adsorption process are obtained. Finally, a preliminary experiment on a pre-treated waste water finally shows that the filtration material is potentially interesting for an industrial application
Brisson, Olivier. "Elaboration et caractérisation de monocristaux de AgGaX₂ (X = S, Se) pour l'optique non-linéaire dans l'infrarouge : approche par simulation numérique de l'hydrodynamique dans la phase fluide". Bordeaux 1, 1995. http://www.theses.fr/1995BOR10518.
Texto completoGatt, Antoine. "Instabilité des freins aéronautiques : Approche transitoire et multi-physique". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEC024.
Texto completoThese vibrations are a threat for the brake and landing-gear structural integrity and represent an issue in terms of integration. Thus Safran Landing Systems has to comply with aircraft manufacturers’ strict requirements on the vibration amplitude its product is likely to generate. Compliance to these requirements is assessed by long and costly braking test campaigns. The objective of the research presented here is to reproduce by simulation the brake dynamic instabilities with numerical tools that could be integrated in the design process. Brake squeal has been a research topic since the early XXth century. However it remains a rather ill-understood phenomenon, especially in aeronautics. Unstable vibrations regularly appear on the whole 0-2kHz frequency spectrum. In the last decade, an instability located around 200 Hz called whirl 2 persistently appeared on the newly developed wheel and brake assemblies, sometimes exhibiting critical vibration amplitudes. Consequently, Safran Landing Systems wishes to develop numerical tools able to simulate both the occurrence and the amplitudes associated with friction-induced instabilities, especially with the whirl 2 mode. In the first part of this report, an experimental analysis of the brake is conducted, on both laboratory and in operational set-ups. The modelling of the wheel and brake assembly using the finite element method is then described. The system stability in a Lyapunov’s sense is studied and shows good correlation in both frequencies and mode shapes with the experiments. This finite element model is too big to be used to perform the transient simulation of the nonlinear amplitudes. In the second part, two reduction methods, tailored to the complex aircraft brakes architectures, are thus presented. The first method is a semi-analytical. It shows excellent performances up to 500 Hz. The second reduction method is the double modal synthesis, implemented under its classical version. It is then successfully improved and called "complex double modal synthesis". The third part is dedicated to the study of the nonlinear dynamics of the whirl 2 through transient analyses. The nonlinear amplitudes simulation requires taking into account the relevant nonlinear brake behavior. However, it is first observed that, contrary to a commonly accepted hypothesis, the contact nonlinearities located at the friction interfaces cannot single-handedly account for the vibration amplitudes saturation observed in the tests. The need to identify the relevant physical phenomena leads then to consider the interaction between the squealing brake structure and its hydraulic command circuit. The modelling of the hydro-mechanical coupling provides an unprecedented insight and allows to prescribe design rules. Finally, we study the impact of dry friction in the peripheral contacts between the braking discs and the structure. This phenomenon, neglected until now, appears to have a major influence. Sensitivity studies exhibit a good correlation with tests, allowing to highlight, in a robust manner, the impact of brake design and braking scenarii on the nonlinear vibration amplitudes
Boutron, Olivier. "Étude de l'influence de l'hydrodynamique sur le transfert de produits phytosanitaires en fossés agricoles : approche expérimentale et numérique". Lyon 1, 2009. http://n2t.net/ark:/47881/m6xg9p3z.
Texto completoThe aim of this work was to better understand the influence of hydrodynamics on the transfer of pesticides in water flows in agricultural ditches. Special attention was given to four parameters: i) the speed of the surface water flow, ii) the submergence, defined as the mean ratio between the height of the bedforms and the water depth, iii) the shape of the bedforms and iv) the water content of the bed substrate before contamination by pesticides. The influence of these various parameters was investigated with an experimental flume, using a standard of substrate made of hemp fibres. Hemp fibres were chosen as a simplified model of natural substrates such as grass, dead leaves, decaying vegetation, straw and sediments, which are rather complex and heterogeneous. Hemp fibres were selected from preliminary laboratory studies which allowed to compare the adsorption and desorption characteristics of various pesticides for different fibres often used in the geotextile industry (jute, linen, hemp, polyamide, polypropylene and polyester). The flume experiments were designed in order to assess the influence of the four parameters mentioned above. The comparison between the different experiments shows that an increase in surface water speed results in an increase in the amount of pesticides transferred from the water to the bed substrate and the transfer kinetics. A similar result is observed when increasing the submergence, or when going from small sinusoidal bedforms to larger rectangular bedforms. In addition, the data show that the transfer of pesticides from surface water to the bed substrate is strongly decreased when the substrate was saturated with water at the beginning of the experiments. Also, it appears that there is a link between the influence of the differents parameters. When considering the long time duration and the cost of the experiments, it was decided to use a model from the literature which was adapted and used to confirm and extend the interpretation of the experimental data
Re-Bahuaud, Jordan. "Apports d'une approche couplée physique et géochimie des eaux souterraines pour caractériser les fonctionnements hydrodynamiques transitoires. Cas de la plaine alluviale du Forez". Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2012. http://tel.archives-ouvertes.fr/tel-00783984.
Texto completoRe-Bahaud, Jordan. "Apports d’une approche couplée physique et géochimie des eaux souterraines pour caractériser les fonctionnements hydrodynamiques transitoires. Cas de la plaine alluviale du Forez". Thesis, Saint-Etienne, EMSE, 2012. http://www.theses.fr/2012EMSE0666/document.
Texto completoThe Water Management Scheme in the Forez plain (France 42) has concluded to a degradation of the water resources and a serious pollution of the shallow aquifers by nitrogen and pesticides. These issues require a sustainable and balanced management of the water resources. A part of the water demand is met by groundwater. The exploited groundwater come from: shallow alluvial formations exploited for irrigation and drinking water and deep aquifers in sedimentary basin under the alluvium. Mineral waters from the deep aquifers are exploited for thermo-mineral activities and bottling.The analysis of the data available in the studied area revealed a lack of knowledge in the understanding of the groundwater flow in the shallow aquifers. Is not sufficient to explain how the water resource varies with time and the origin of the recharge of the shallow aquifers. As consequence, this thesis work will focus on these two main topics: - Identification of the transient functioning of the aquifers based on a physical characterization of groundwater flow. This method is based on piezometric head analysis carry out on 4 stations with continuous measurements and numerical modeling to compare with the observed piezometric fluctuations.- Identification of the origin of the recharge of the alluvial aquifers through a geochemical characterization of groundwater flow (major ions and isotopes δ180, δ2H, δ13C and A14C). This approach established the partial contribution of the deep aquifers to the groundwater flow in the shallow alluvium. This methodology based on a coupled geochemical and physical approach allows to assess the vulnerability of the studied aquifers and contributes to improve the future water resources management in this area
Bailly-Comte, Vincent. "Interactions hydrodynamiques surface/souterrain en milieu karstique : approche descriptive, analyse fonctionnelle et modélisation hydrologique appliquées au bassin versant expérimental du Coulazou, Causse d'Aumelas, France". Phd thesis, Montpellier 2, 2008. http://www.theses.fr/2008MON20087.
Texto completoL'étude hydrodynamique de ce système karst/rivière s'appuie sur un dispositif expérimental adapté à l'observation des phénomènes hydrologiques (pluie, ruissellement) et hydrogéologiques (piézométrie en forage et dans les drains karstiques, suivi hydrodynamique des exutoires du système) très rapides et très intenses. La dynamique de ces écoulements est liée au contexte climatique Méditerranéen mais aussi aux structures de drainage en surface et en souterrain qui permettent un transfert et un transit très rapide des eaux au sein du système karst/rivière.
Une description hydrodynamique classique est complétée par une approche fonctionnelle des échanges karst/rivière dans le but de mieux comprendre le fonctionnement hydrodynamique d'un tel système et de mettre en avant des indicateurs utilisables dans une démarche de modélisation des échanges surface/souterrain. Un premier modèle est présenté dans la dernière partie de ce document.
Younsi, Amina. "Simulations des effets des écoulements sur la croissance cristalline d'un mélange binaire. Approche par méthode de Boltzmann sur réseau". Palaiseau, Ecole polytechnique, 2015. https://theses.hal.science/tel-01221833/document.
Texto completoBailly-Comte, Vincent. "Interactions hydrodynamiques surface/souterrain en milieu karstique : approche descriptive, analyse fonctionnelle et modélisation hydrologique appliquées au bassin versant expérimental du Coulazou, Causse d'Aumelas, France". Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2008. http://tel.archives-ouvertes.fr/tel-00319965.
Texto completoL'étude hydrodynamique de ce système karst/rivière s'appuie sur un dispositif expérimental adapté à l'observation des phénomènes hydrologiques (pluie, ruissellement) et hydrogéologiques (piézométrie en forage et dans les drains karstiques, suivi hydrodynamique des exutoires du système) très rapides et très intenses. La dynamique de ces écoulements est liée au contexte climatique Méditerranéen mais aussi aux structures de drainage en surface et en souterrain qui permettent un transfert et un transit très rapide des eaux au sein du système karst/rivière.
Une description hydrodynamique classique est complétée par une approche fonctionnelle des échanges karst/rivière dans le but de mieux comprendre le fonctionnement hydrodynamique d'un tel système et de mettre en avant des indicateurs utilisables dans une démarche de modélisation des échanges surface/souterrain. Un premier modèle est présenté dans la dernière partie de ce document.
Ceratti, Davide Raffaele. "Viability of nanoporous films for nanofluidic applications". Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066482/document.
Texto completoThis thesis had a dual purpose: i) the development of nanofluidic devices through not lithographic, cheap and scalable bottom-up approach ii) the understanding of nanofluidic phenomena both through experiments and simulations. Mesoporous thin films, in particular Pillared Planar Nanochannels (PPNs), were prepared and utilized to study the capillary infiltration of liquids in nanostructures and have been tested for future nanofluidic applications like separations and nanoconfined reactions. Non organized mesoporous films have also been studied to determine the relationship between nanostructure characteristics and infiltration speed. It has been also demonstrated that in the case of porosities with reduced bottle-necks capillary penetration is performed through a vapor mediated mechanism The samples were prepared by dip-coating. A novel method of preparation based on the substitution of a large part of the deposing solution in dip-coating with an inert fluid has been developed in order to strongly reduce the fabrication costs and allow the preparation of larger samples. Moreover advancement in control of the dip-coating technique in “acceleration-mode” to produce thickness gradients has been developed and some potential application linked to fluidics shown. Finally a part of the effort of this thesis has been placed in the modeling of the electro-osmotic phenomenon in nanostructures through a rather novel simulation method, Stochastic Rotational Dynamics, which takes into account the hydrodynamics and the other interactions inside a nanofluidic system. Validations of the method and further investigations in particular nanofluidic conditions have been performed
Ducrozet, Guillaume. "Modélisation des processus non-linéaires de génération et de propagation d'états de mer par une approche spectrale". Phd thesis, Université de Nantes, 2007. http://tel.archives-ouvertes.fr/tel-00263596.
Texto completoUn traitement original de la génération de houle non-linéaire est proposé. Il permet l'accès à des simulations de champs de vagues tridimensionnels complexes, fortement cambrés, dans un bassin de houle. Diverses comparaisons avec des expériences menées dans le bassin du Laboratoire de Mécanique des Fluides de l'ECN sont présentées.
Des simulations océaniques, en milieu ouvert, sont également proposées. Un intérêt particulier est porté à l'étude de l'apparition des vagues scélérates au sein de l'océan. L'importance des effets non-linéaires est pointée ainsi que l'aptitude de la méthode à modéliser de tels phénomènes. Des comparaisons avec les méthodes classiquement employées dans ce genre de problématique indiquent l'intérêt de l'approche utilisée ici.
La résolution du problème de tenue à la mer est également envisagée. L'utilisation de la méthode HOS dans les codes couplés, développés au Laboratoire de Mécanique des Fluides (potentiel, RANS, SPH), est envisagée. Elle permettra la description précise de la houle incidente ; le couplage est mis en place et validé sur un certain nombre de cas d'application.
Jatiault, Romain. "Les émanations naturelles d'hydrocarbures lourds depuis les sédiments vers l'hydro-atmosphère : approche intégrée multiéchelle dans le bassin profond du bas-congo". Thesis, Perpignan, 2017. http://www.theses.fr/2017PERP0047/document.
Texto completoThe Lower Congo Basin is a passive margin, affected by strong salt tectonics. Natural escapes of heavy hydrocarbons observed in the area have major impacts on the society, ecology, biology, and the economy. The aim of this work is to understand the mechanisms of these systems, from the mobilisation in the sediments towards the seafloor outlets and subsequently towards the sea surface. This study combines data analysis from spatial imagery, oceanography, geochemistry and marine geophysics in order to get a multi-scale integrated vision of the natural seepage situation in the Lower Congo Basin. The analysis of spatial imagery data shows that in the study area, the hundred active seeps sites expel a hydrocarbons volume of 4400 m3 per year, following an intermittent mechanism with miscellaneous frequencies from one site to another. We connected visible hydrocarbon slicks at the sea surface with seabed structures by integrating current measurements across the water column. Seafloor structures correspond to clustered pockmarks of high seismic amplitude located at the rim of salt diapirs and to clusters of mounds composed of highly degraded oil outwards. In sediments, geophysical anomalies form vertical chimneys, delimited by the seismic reflector associated with the base of gas hydrates stability downwards. The spatial correspondence of geophysical criteria enabled to inventory the potentially active sites on the geophysical data. Only 40% of these sites are associated with recurring oil slicks at the sea surface
Barbel-Périneau, Aurore. "Caractérisation du fonctionnement de la zone non saturée des aquifères karstiques : Approche directe par études hydrodynamiques et hydrochimiques sur le Bassin de Recherche, d'Expérimentation et d'Observation de Fontaine de Vaucluse – Laboratoire Souterrain à Bas Bruit de Rustrel – Pays d’Apt". Thesis, Avignon, 2013. http://www.theses.fr/2013AVIG0046/document.
Texto completoThe first study of karst aquifers unsaturated zone (UZ) functioning, by direct access, was conducted on the experimental area of the Fontaine de Vaucluse, including the underground gallery of the LSBB. This gallery intersects arbitrarily, within the UZ, the karst network and flow paths. Observed flows are distributed throughout the gallery corresponding to different limestone thicknesses (30 to 514m). 45 flow points were observed and followed at least once. The hydrodynamic and hydrochemical monitoring over 8 years show that: (i) the flows spatial and temporal organisation is a function of depth and the fracturing density, (ii) the hydrodynamic and hydrochemical flows signatures are based on rainfall amount also as the initial state of the system (iii) in order to precise the conceptual model of karst aquifers is necessary to consider the nonlinearity of the hydrodynamic system’s responses.Three flow components are deduced: (i) a slow component, permanent, which is active regardless of hydrological conditions, and is characterized by significant residence time, (ii) a fast component, active only during strong recharge periods as marked by infiltration tracers. This component is characterized by low residence time and (iii) an intermediate component, highlighted by hysteretic behavior, as marked also by the infiltration tracers and is characterized by intermediate residence times. Considering the hysteresis phenomenon in UZ modeling by these direct observations confirms earlier conceptual models. The ultimate goal is to contribute to the development of a karst aquifer model, which could be transposed to other Mediterranean karst systems
Tissafi, Bouchra. "Résolution couplée des équations de l'électromagnétisme et du transport en 3D pour des applications THz : modélisation et optimisation du photo-commutateur". Paris 11, 2010. http://www.theses.fr/2010PA112313.
Texto completoThis thesis investigates the three-dimensional modelling of Maxwell equations coupled with Boltzmann equation in THz devices. This work is part of the search for new optoelectronic devices operating at THz frequency. The modelled device in this thesis is a metal-semiconductor-metal photoconductive switch (PCS) fabricated on InP which is fully compatible with the technology of telecom circuits. This thesis deals with three important topics: 1/ The dévelopment of IEF-made code "Maxtra3D" that coupled equations of electromagnetism and Transport (model drift-diffusion and hydrodynamic model). Thus, to confirm the relevance of our modelling choices, we compare our software based on the FDTD method with variable mesh with two other software: IRCOM software that is based on FDTD method with constant mesh and LGEP software based on finite element method. 2/ Evaluation of loss origins in the coplanar waveguide that provides the environment for the generation and propagation of the THz wave. 3 / Parametric study and optimization of PCS. Other PCS geometries were modelled as part of this optimization
Dakoure, Denis. "ETUDE HYDROGEOLOGIQUE ET GEOCHIMIQUE DE LA BORDURE SUD-EST DU BASSIN SEDIMENTAIRE DE TAOUDENI (BURKINA FASO - MALI) - ESSAI DE MODELISATION". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2003. http://tel.archives-ouvertes.fr/tel-00608860.
Texto completoCeratti, Davide Raffaele. "Viability of nanoporous films for nanofluidic applications". Electronic Thesis or Diss., Paris 6, 2015. http://www.theses.fr/2015PA066482.
Texto completoThis thesis had a dual purpose: i) the development of nanofluidic devices through not lithographic, cheap and scalable bottom-up approach ii) the understanding of nanofluidic phenomena both through experiments and simulations. Mesoporous thin films, in particular Pillared Planar Nanochannels (PPNs), were prepared and utilized to study the capillary infiltration of liquids in nanostructures and have been tested for future nanofluidic applications like separations and nanoconfined reactions. Non organized mesoporous films have also been studied to determine the relationship between nanostructure characteristics and infiltration speed. It has been also demonstrated that in the case of porosities with reduced bottle-necks capillary penetration is performed through a vapor mediated mechanism The samples were prepared by dip-coating. A novel method of preparation based on the substitution of a large part of the deposing solution in dip-coating with an inert fluid has been developed in order to strongly reduce the fabrication costs and allow the preparation of larger samples. Moreover advancement in control of the dip-coating technique in “acceleration-mode” to produce thickness gradients has been developed and some potential application linked to fluidics shown. Finally a part of the effort of this thesis has been placed in the modeling of the electro-osmotic phenomenon in nanostructures through a rather novel simulation method, Stochastic Rotational Dynamics, which takes into account the hydrodynamics and the other interactions inside a nanofluidic system. Validations of the method and further investigations in particular nanofluidic conditions have been performed
Bourgoin, Adrien. "Modélisation de la turbulence engendrée par la morphologie dans le Raz Blanchard : approche régionale avec TELEMAC-LES". Thesis, Normandie, 2019. http://www.theses.fr/2019NORMC205/document.
Texto completoNowadays tidal currents are considered a promising renewable energy source. Many worldwide projects involve the installation of different types of marine current energy converters. The characterisation of marine resources is therefore essential to increase efficiency of energy production. Areas with high hydroturbine potential are particularly subject to multi-scale turbulence, ranging from small vortices able to cause large fatigue loads, to large vortices capable of disrupting turbine production. A better knowledge of the generation of these eddies and their propagation is essential. This is the purpose of the ANR/FEM THYMOTE project (Turbulence, Hydrolienne, Modélisation, Observations et TEsts en bassin) studying one of the most promising sites in Europe: the Alderney Race. One of the questions raised concerns the ability of large morphological structures on the seabed to produce eddies. The adopted method uses a 3D regional model to cover the area occupied by these bedforms.Regional models such as TELEMAC-3D use a turbulent URANS (Unsteady Reynolds Averaged Navier Stokes) closure, with for example the $k-\varepsilon$. This approach does not allow a detailed description of the instability of turbulence. However, thanks to the increase in computing resources, the large scale method (LES) becomes feasible. This is based on flow filtering, and consists of simulating only the largest turbulence scales, whereas the smaller ones are modeled. The TELEMAC-3D code was modified during this thesis in order to introduce this turbulent closure. The code developed allows free surface flows to be simulated over a wide range of scales from turbulence to tidal propagation. The TELEMAC-LES code has been validated on the basis of experimental results from the literature. It is then used to study turbulent flows in the Alderney Race using a nesting strategy. The LES method allows a detailed description of the turbulence of these environments. It finally leads to the identification of energetic vortex structures, and thus the definition the most appropriate zones for the installation of tidal turbines
Lorette, Guillaume. "Fonctionnement et vulnérabilité d'un système karstique multicouche à partir d'une approche multi-traceurs et d'un suivi haute-résolution : application aux Sources du Toulon à Périgueux (Dordogne, France)". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0116/document.
Texto completoThis work is included in an approach for a better knowledge of karst aquifers. For this, the Toulon Springs pilot site was chosen, and provides the opportunity to study relationships between multilayered karst aquifers of the northern edge of the Aquitaine sedimentary basin. Toulon Springs are major regional springs and are located in Périgueux (Dordogne County, France). They have been supplying water to the metropolitan area of Périgueux since 1832.This work aim to test an innovative multitracer approach coupled with a physicochemical high-resolution auto-monitoring to characterize functioning and vulnerability of a multilayered karst aquifer.The use of a coupled hydrodynamic and hydrochemical approach has highlighted Toulon Springs supply by a deep and captive aquifer, in addition to a more subsuperficial aquifer. This information has been incorporated into the global hydrogeological situation of the study area to propose a new delineation of Toulon Springs hydrogeological cathment.The use of a high-resolution monitoring enables to specify the hydrogeological functioning of the studied karst system. The analysis performed on several flood events, identify that mass transfer can range from a few days to a few weeks.The use of nitrate isotope (δ15N-NO3- ; δ18O-NO3-) enables to identify two main nitrate sources in both surface water and groundwater: (i) inorganic fertilizer; (ii) sewage from individual house.The last part of this work was to analyse Toulon Springs temporal vulnerability during floods to marker of contamination such as particles, dissolved organic carbon, nitrate, and bacteria. Hence, several water type from surface runoff, unsaturated zone and saturated zone were identify as responsible of contaminant transfer: (i) water from saturated zone is responsible of vulnerability to mineral particles ; (ii) water from unsaturated zone is responsible of vulnerability to nitrare ; (iii) water from surface runoff is responsible of vulnerability to bacteria contamination
Dakoure, Denis. "Etude hydrogéologique et géochimique de la bordure sud-est du bassin sédimentaire de Taoudeni (Burkina Faso - Mali) : essai de modélisation". Paris 6, 2003. http://www.theses.fr/2003PA066521.
Texto completoElMimouni, Abdelhadi. "Approche expérimentale de suivi de la dynamique morphosédimentaire du littoral d'Essaouira, Maroc : implications pour un aménagement raisonné". Littoral, 2009. http://www.theses.fr/2009DUNK0251.
Texto completoEssaouira beach borders a famous and densely populated bay characterised by a complex and fragile environment that is presently, however, in a state of geomorphic equilibrium. The processes prevailing in the bay, under the triple command of winds, waves, and to a lesser extent, tides, vary considerably in time and space, and could be durably modified in the future under growing human pressures and unreasonable planning. In order to understand the sedimentary morphodynamics of this beach and of the nearshore zone, several field experiments, involving topographic, hydrodynamic and grain-size monitoring, were carried out from 2004 to 2006. The experiments were aimed at highlighting seasonal, intra-annual and monthly patterns of evolution of the beach, especially under the influence of a nearby wadi, the Ksob, which is the main sediment purveyor of the beach. An additional objective of the study was also to monitor variations in the beach sedimentbudget following a major wadi flooding event. The hydrodynamics measurements involved wave and current parameters and were analysed in the light of the marked changes in wind intensity affecting the area. The currents flow dominantly alongshore to the south and southwest north and south of the bay, and exhibit bi-directional flow along the bay beach under both calm and high-energy conditions. The latter bay currents are more pronounced during high-energy conditions. The topographic data highlight longshore and cross-shore variations in beach morphology and their spatio-temporal changes. Essaouira bay comprise a complex beach sediment cell composed of several micro-cells. The Ksob plays an important role in the dynamics of these cells. The dominant winds from the north transport significant quantities of sand to the south in the form of barkhanes that are trapped in the esturary of the Ksob. During river flood events, these sands, as well as fresh inputs brought in by the wadi, are injected in the nearshore zone of Essaouira bay, and are subsequently redistributed onshore, and along the beach by tidal currents ans currents generated by refracted swell. A planned resort construction in the Ksob estuary as well as the projected new Zerrar dam 30 km upstream of the bay could result in serious disequilibrium of the fragile sedimentary system of the bay
Drouzy, Marion. "Etude de l'impact terrigène naturel et anthropique sur un système lagonaire tropical grâce à une approche de modélisation 3D hydro-sédimentaire liée à un réseau de mesures". Electronic Thesis or Diss., Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0455.
Texto completoThis thesis presents the adaptation of a hydrodynamic model to the lagoon of New Caledonia, potentially impacted by nickel activity. Hydrodynamic modeling is a tool for estimating and managing spatiotemporal risks for downstream areas. The MARS3D model has been implemented to study the dispersion of a dissolved material (tracer) from rivers. The tracking of this tracer, under the influence of different physical forcings, made it possible to apprehend the fate of dissolved pollutants potential from the mining industry. A residence time characteristic of hydrodynamics, calculated using the model and called the local e-Flushing time (eFTs), has been proposed to determine the zones with the longest residence times, and therefore the prediction of stagnant areas of possible pollutants in the water column, depending on wind and tidal conditions. This indicator is a predictive information tool, easily and quickly exploitable in an approach to estimate pollution risks. The last phase of the thesis work was the implementation of the coupling between the existing hydrodynamic module and the sedimentary module. An important test phase of the various parameterization options was necessary to reproduce the sedimentary characteristics measured in situ. Several pieces of information remain missing, which makes it difficult to use the module for forecasting purposes. However, the influence of terrigenous inputs on the entire modeled domain has been highlighted, raising the potential pollution risks via fixation of contaminants on deposited particles
Perineau, Aurore. "Caractérisation du fonctionnement de la zone non saturée des aquifères karstiques : Approche directe par études hydrodynamiques et hydrochimiques sur le Bassin de Recherche, d'Expérimentation et d'Observation de Fontaine de Vaucluse - Laboratoire Souterrain à Bas Bruit de Rustrel - Pays d'Apt". Phd thesis, Université d'Avignon, 2013. http://tel.archives-ouvertes.fr/tel-00990290.
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