Tesi sul tema "Eau – Dynamique des fluides"
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Albagnac, Julie. "Dynamique tridimensionnelle de dipôles tourbillonnaires en eau peu profonde". Phd thesis, Toulouse 3, 2010. http://oatao.univ-toulouse.fr/9847/1/Albagnac_9847.pdf.
Chatelain, Mathieu. "Flux dissous à l'interface eau-sédiment sous des écoulements oscillants". Paris 6, 2010. http://www.theses.fr/2010PA066154.
Lahaye, Noé. "Dynamique, interactions et instabilités de structures cohérentes agéostrophiques dans les modèles en eau peu profonde". Electronic Thesis or Diss., Paris 6, 2014. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2014PA066289.pdf.
Coherent structures are ubiquitous features of atmospheric and oceanic flows. Their associated meso- and large scale circulation is in geostrophic equilibrium. However, at increasing Rossby numbers, ageostrophic effects may push the structures away from this equilibrium, and new types of instabilities can also disturb their dynamics. In this thesis, the properties of ageostrophic coherent structures are investigated, mainly by means of direct numerical simulations. This is done in the framework of simplified conceptual models of meso- and large scale oceanic and atmospheric flows, namely Rotating Shallow Water models. The instability of intense vortices (isolated anticyclonic vortices and tropical cyclones) in one-layer and two-layer shallow water models are studied. Direct numerical simulations of the nonlinear saturation of these instabilities allow us to study the properties of the ageostrophic part of the flow, such as the inertia-gravity wave emission and the formation of shocks. Then, quasi-stationary ageostrophic structures are obtained by means of numerical simulations in one-layer and two-layer models. It consists of vortex dipoles or tripoles, either baroclinic or barotropic, which are stable and whose ageostrophic component does not imply inertia-gravity waves emission. Finally, decaying vortex and wave turbulence is studied in the one-layer model. The evolution of the flow for very different initial conditions is discussed and we put the emphasis on the ageostrophic properties of the flow, the wave-vortex coupling and the sensitivity to initial conditions
Lahaye, Noé. "Dynamique, interactions et instabilités de structures cohérentes agéostrophiques dans les modèles en eau peu profonde". Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066289/document.
Coherent structures are ubiquitous features of atmospheric and oceanic flows. Their associated meso- and large scale circulation is in geostrophic equilibrium. However, at increasing Rossby numbers, ageostrophic effects may push the structures away from this equilibrium, and new types of instabilities can also disturb their dynamics. In this thesis, the properties of ageostrophic coherent structures are investigated, mainly by means of direct numerical simulations. This is done in the framework of simplified conceptual models of meso- and large scale oceanic and atmospheric flows, namely Rotating Shallow Water models. The instability of intense vortices (isolated anticyclonic vortices and tropical cyclones) in one-layer and two-layer shallow water models are studied. Direct numerical simulations of the nonlinear saturation of these instabilities allow us to study the properties of the ageostrophic part of the flow, such as the inertia-gravity wave emission and the formation of shocks. Then, quasi-stationary ageostrophic structures are obtained by means of numerical simulations in one-layer and two-layer models. It consists of vortex dipoles or tripoles, either baroclinic or barotropic, which are stable and whose ageostrophic component does not imply inertia-gravity waves emission. Finally, decaying vortex and wave turbulence is studied in the one-layer model. The evolution of the flow for very different initial conditions is discussed and we put the emphasis on the ageostrophic properties of the flow, the wave-vortex coupling and the sensitivity to initial conditions
Marfaing, Olivier. "Contributions à la modélisation fine de la réaction sodium-eau". Electronic Thesis or Diss., Paris 6, 2014. http://www.theses.fr/2014PA066343.
The fine-scale modeling of sodium-water reaction is motivated by its applications to sodium-cooled fast nuclear reactors and experimental irradiation reactors. As shown by several experiments from the literature, the contact between liquid sodium and water gives rise to a gaseous film where the reaction takes place in the form of a gaseous diffusion flame. In this manuscript, we have chosen to focus on the combustion of a liquid sodium drop immersed in an infinite volume of water. Several simplifying assumptions are introduced : in particular, we limit ourselves to the one-dimensional problem.Assuming the gaseous film has constant density, an analytical study shows that the physical state of sodium hydroxide has a strong influence on the behavior of the system : if soda is entirely vaporized, the flame gets choked, while, on the opposite, if it is entirely condensed, a self-similar solution can be exhibited and the combustion is sustained. A numerical algorithm is developed.Then, the previous model is improved by taking into account the gas compressibility. We develop a low Mach number algorithm. The computations show an oscillatory behavior of the one-dimensional film, due to the inertia of water. The calculated reaction rates are found to be in good agreement with Ashworth’s measurements. Initial conditions in the film are unknown : a simplified mechanism of film formation is therefore proposed, and a sensitivity analysis on initial conditions is carried out. The results are seen to be only slightly dependent on the initial state of the system
Beydoun, 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.
Unsaturated 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
Lesaffre, Benoît. "Fonctionnement hydrologique et hydraulique du drainage souterrain des sols temporairement engorgés : débits de pointe et modèle SIDRA : extension des principes théoriques de Boussinesq et Guyon : exemple du champ expérimental d'Arrou (Eure-et-Loir)". Paris 6, 1988. http://www.theses.fr/1988PA066362.
Salman, Aswed Taef Ackerer Philippe. "Modélisation de la pollution de la nappe d'Alsace par solvants chlorés". Strasbourg : Université de Strasbourg, 2009. http://eprints-scd-ulp.u-strasbg.fr:8080/1105/01/THESE_Z-S-Aswed.pdf.
ZORANIC, Larisa. "Étude par dynamique moléculaire de la micro-hétérogénéité dans les mélanges eau-alcools". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2008. http://tel.archives-ouvertes.fr/tel-00813102.
PHAM, Chi-Tuong. "Stabilité et dynamique d'écoulements de fluides parfaits barotropes autour d'un obstacle en présence de dispersion". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2003. http://tel.archives-ouvertes.fr/tel-00006825.
Baig, Muhammad. "Extraction de composant de biomasse lignocellulosique oléagineuse en milieu eau et CO2 subcritique et fonctionnalisation enzymatique". Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20215/document.
This work addresses the integrated biorefining concept (extraction, fractionation, separation of compounds from biomass prior to further transformation) by developing discrete units with the ultimate objective of coupling them to enable a continuous flow configuration. Due to the complexity of solid, there is a need for a sustainable and environmentally friendly pre-treatment technology. Sub-critical water has been used as a solvent for extracting natural compounds in addition to hydrolysis. This work investigated the hydrolysis of carbohydrates (rice bran) and triacylglycerols (TAG; sunflower oil) chosen as models. The attribute of subcritical water (ion product and dielectric constant) in continuous flow reactors built for the purpose, allowed almost quantitative hydrolysis of hemicellulose and TAG. The effect of adding CO2 and therefore carbonic acid was positive on the hydrolysis of hemicellulose. Further, free fatty acids were transformed to ethyl esters using lipase within continuous flow super critical CO2 resulting in 95% yield. The hydrolysis and esterification reaction kinetics were studied. To address the complex interplay between multiple processing parameters response surface methodologies (RSM) were developed. Using the empirical data the models were successfully validated, therefore showing the utility of the RSM to assist process development. The important question of solubility of extractible in subcritical water was also addressed, through the development of a prediction method, validated with experimental data. In summary this work shows the possibility of applying the innovative Integrated Biorefining concept under continuous flow conditions -instead of the current application under batch conditions- for producing valuable compounds
Yehya, Mohamad. "Propriétés de transfert dans le béton par imagerie neutronique". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI103/document.
For civil engineering structures, especially containment buildings during a severe accident, the permeability of concrete is a key issue. Current permeability measurements allow only average (structural) magnitudes, which are not suitable for heterogeneous samples (cracks and/or reinforcements). Understanding the details of fluid flow is crucial because of the implications of preferred pathways (steel/concrete interface, cracks, etc.). The aim of this thesis is to propose a new methodology, and to test a new experimental setup, using neutron imaging at the D50 beam line at the Institute Laue Langevin in Grenoble to measure flow directly. The test consists of injecting normal water (H2O) under high pressure, into a concrete sample casted and saturated with heavy water (D2O), in order to follow the evolution of a waterfront over time by difference of attenuation between these two waters. An experimental campaign was launched on concrete specimens in different configurations (proper concrete, cracked concrete and concrete with reinforcement) and measurements of local permeability in singularities (cracked zone, reinforcement-concrete interface, etc.) were done. Tests have shown that classical permeability measurements are underestimated and flows in concrete are controlled by defects
Goy, Laurent. "Contribution à l'analyse du comportement des produits de fission en situation accidentelle dans un réacteur à eau pressurisée". Lyon 1, 1998. http://www.theses.fr/1998LYO19004.
Mihiretie, Besira. "Effets mécaniques de la lumière sur des particules anisotropes micrométriques et dynamique du mouillage à l’interface eau-air". Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14813/document.
We report experiments on ellipsoidal micrometre-sized polystyrene particles. The particle aspect ratio (k) varies between about 0.2 and 8. These particles are manipulated in water by means of a moderately focused laser beam. We observe the levitation and the dynamical state of each particle in the laser beam, in bulk water or in contact to an interface (water-glass, water-air, water-oil). In the first part, we show that moderate-k particles are radially trapped with their long axis lying parallel to the beam. Conversely, elongated (k>3) or flattened (k<0.3) ellipsoids never come to rest, and permanently “dance” around the beam, through coupled translation-rotation motions. The dynamics are periodic or irregular (akin to chaos) depending on the particle type and beam characteristics. We propose a 2d model that indeed predicts the bifurcation between static and oscillating states. In the second part, we apply optical levitation to study the transition from total to partial wetting of the particles at the water-air interface. We show that the dynamics of the transition is about independent of particle shape, and mainly governed by the pinning-depinning mechanism of the contact line
Landazuri, Gomez Gabriel. "Les études de la dynamique du système micellaire P103/Eau et système de rhéoépaississement CTA-n-Fluorobenzoato". Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00955891.
Fevrier, Laureline. "Transfert d'un mélange Zn-Cd-Pb dans un dépôt fluvio-glaciaire carbonate : approche en colonnes de laboratoire". Lyon, INSA, 2001. http://theses.insa-lyon.fr/publication/2001ISAL0071/these.pdf.
The use of stormwater infiltration basins in urban area can generate a risk of contamination for soils and groundwater. The aim of this work is ta increase the knowledge of the hydraulic and the chemical mechanisms implied in the transfer of pollutants. The porous matrix studied is a carbonated fluvio-glacial deposit usually found in the infiltration basins of the Lyon area. Some columns were designed at the laboratory scale, with the fluvio-glacial deposit sieved at 1 cm. The pollution studied was a mixture of Zn-Cd-Pb - 1 o•3 mol. -1. Some flow tracer. Experiments coupled with modeling (MIM model) were used to characterize the hydrodynamic behaviour of the columns, as a function of water content and flow rate. At saturation, the flow is divided in mobile (50 %) and immobile regions whereas for unsaturated conditions, the flow is more homogeneous. This property seems to be a consequence of the particle size distribution of the fluvio-glacial deposit. The interactions between the metals and the fluvio-glacial deposit were studied thanks to batch and transfer experiments, coupled with modeling (PHREEQC model). From a qualitative point of view, the main reactions are the dissolution of the fluvio-glacial deposit's calcite, the metals precipitation in a carbonated form (cerusite and hydrocerussite for Pb, an unknown mixed specie for Cd and Zn) and the cationic exchange reactions. During the transfer, the metals retention is governed by the chemical kinetic dissolution of the calcite and by the physical kinetic exchange between the mobile and the immobile regions. The retention is maximized for transfer in unsaturated conditions and law flow rates
Maes, Pauline. "Circulations de fluides et interactions eau/roche passées et actuelles dans la pile sédimentaire du site de Meuse/Haute-Marne : apport des isotopes du Sr et conséquences". Montpellier 2, 2002. http://www.theses.fr/2002MON20174.
Dailloux, Damien. "Video measurements of the Adour plume dynamic and its surface water optical characteristics". Pau, 2008. http://www.theses.fr/2008PAUU3042.
The suspended particulate matter (SPM), rejected into the ocean by a river, is often visualized by the presence of a turbid surface plume. These SPM can be associated with organic or metal contaminants. It is thus necessary to understand the mechanisms which control their dispersion in order to evaluate water quality in the adjacent areas of a river mouth. Recently, the video techniques were used to study coastal dynamics. These techniques allow to automatically acquire high frequency data with a resolution of centimetre to hundred meters. This study presents a single use of a classic digital camera to study the Adour surface plume dynamic and the optical characteristics of its water
Soetens, Jean-Christophe. "Développement d'un programme de dynamique moléculaire incluant des modèles électrostatiques élaborés : application à l'étude de fluides polarisables et de solutions ioniques". Nancy 1, 1996. http://www.theses.fr/1996NAN10241.
Mihiretie, Besira. "Effets mécaniques de la lumière sur des particules anisotropes micrométriques et dynamique du mouillage à l'interface eau-air". Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00869331.
Marfaing, Olivier. "Contributions à la modélisation fine de la réaction sodium-eau". Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066343.
The fine-scale modeling of sodium-water reaction is motivated by its applications to sodium-cooled fast nuclear reactors and experimental irradiation reactors. As shown by several experiments from the literature, the contact between liquid sodium and water gives rise to a gaseous film where the reaction takes place in the form of a gaseous diffusion flame. In this manuscript, we have chosen to focus on the combustion of a liquid sodium drop immersed in an infinite volume of water. Several simplifying assumptions are introduced : in particular, we limit ourselves to the one-dimensional problem.Assuming the gaseous film has constant density, an analytical study shows that the physical state of sodium hydroxide has a strong influence on the behavior of the system : if soda is entirely vaporized, the flame gets choked, while, on the opposite, if it is entirely condensed, a self-similar solution can be exhibited and the combustion is sustained. A numerical algorithm is developed.Then, the previous model is improved by taking into account the gas compressibility. We develop a low Mach number algorithm. The computations show an oscillatory behavior of the one-dimensional film, due to the inertia of water. The calculated reaction rates are found to be in good agreement with Ashworth’s measurements. Initial conditions in the film are unknown : a simplified mechanism of film formation is therefore proposed, and a sensitivity analysis on initial conditions is carried out. The results are seen to be only slightly dependent on the initial state of the system
Sanchez, Célia. "Hydrodynamique et transfert de matière gaz-liquide dans un nouveau contacteur à haute énergie : application à la désodorisation de l'air en assainissement". Rennes 1, 2006. http://www.theses.fr/2006REN1S159.
Salman, Aswed Taef. "Modeling of the contamination in the Alsatian aquifer by chlorinated solvents". Université Louis Pasteur (Strasbourg) (1971-2008), 2008. http://www.theses.fr/2008STR13201.
Cochard, Thomas. "Injection de tensioactif pour la récupération assistée du pétrole : implication sur les lois régissant les écoulements eau-hydrocarbure-tensioactif en milieu poreux". Electronic Thesis or Diss., Paris 6, 2017. http://www.theses.fr/2017PA066647.
The main objective of the PhD is to study experimentally the oil mobilization using surfactant in a porous media below the residual oil saturation. At the residual oil saturation, the oil network is disconnected and organized in ganglia of different sizes and shapes all along the sample. This residual oil is difficult to produce in the classical conditions of water flooding because of capillary trapping created by the interfacial tension between oil and water. Injection of surfactant is able to mobilize the remaining oil at flow rates consistent with the real case of an oil mature reservoir. The use of surfactant allows lowering the interfacial tension by several orders of magnitude, towards ultra-low values (10-3 mN/m), strongly decreasing the capillary forces and so, mobilizing the oil. The first main study of the PhD work was to characterize the displacement of the surfactant injected in a sandstone sample in monophasic conditions (without oil). Breakthrough curves have been analyzed in term of dispersivity and adsorption. Experiments have shown that a better way to model the surfactant transport is to use a Langmuir kinetic adsorption model. For the diphasic case, we have developed a microfluidic 2D system with a random pore geometry of controlled conditions. The experiments are based on the injection of a small ganglia through a central channel, then, a surfactant flood is generated. The aim is to see how ganglia are displaced within the micromodel. New mechanisms have been identified and a way to model those phenomena has been proposed. A better understanding of surfactant and oil transport in porous media is key for chemical enhanced oil recovery processes
Chatellier, Patrice. "Simulation de l'hydrodynamique des chenaux d'oxydation par l'utilisation des équations de Navier-Stokes associées au modèle k-epsilon : évaluation de la vitesse de circulation". Toulouse, INSA, 1991. http://www.theses.fr/1991ISAT0027.
Guimard, Laura. "Étude du comportement et modélisation d’une installation de dessalement d’eau de mer par distillation soumise à des régimes transitoires". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1025/document.
Demand for water will continue to increase over the next decades, leading to more stress on limited resources and ecosystems. However, ¾ of the Earth is water and 97% of it is seawater. Therefore, it is highly interesting to desalinate seawater. It is within this framework that this work was carried out. The goal of this PhD was to model desalination plants, based on the Multiple-Effect Distillation (MED) process, when they are operated under dynamic conditions. The MED plants are mature desalination processes with high energetic performances and are very flexible to load variations. For this study, a coupling between a MED plant and a renewable energy source, therefore transient, was assumed. To study the potential and the feasibility of such an association, a dynamic model representative of the MED plants was developed. With this, it is now possible to study the evolution of all the variables that have a consequence on the plant’s performances as well as to identify which variables are the most critical to the dynamic operation of the MED plant. This model was then combined with a concentrated solar power plant to conclude about the potential of this coupling. To assure an optimal operation of the MED plant under dynamic conditions, a regulation strategy was developed and implemented
Molle, Boris. "Etude des propriétés dynamiques de structures cellulaires formées dans un système eau/huile/surfactant/alcool". Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10249.
Zouhri, Lahcen. "Structure et modélisation hydrodynamique de l'aquifère de la Mamora (Maroc)". Lille 1, 2000. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2000/50376-2000-7.pdf.
Ben, Slimane Férid. "Méthodologie d'étude et modélisation du transport de polluants organiques en milieux poreux naturels : application à l'étude de deux cas de pollutions issues de l'industrie du bois". Vandoeuvre-les-Nancy, INPL, 1997. http://www.theses.fr/1997INPL081N.
Stref, Philippe. "Application à grande échelle d'un modèle hydrodispersif tridimensionnel". Montpellier 2, 1987. http://www.theses.fr/1987MON20068.
Martin, Xavier. "Modélisation d'écoulements fluides en milieu encombré d'obstacles". Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4759/document.
This document focuses on the modeling of compressible flows in one-dimensional (1D) pipes with variable cross-section, and in two or three-dimensional domains containing many small obstacles. The basic motivation is urged by the modeling of flows in the coolant circuit of pressurised water reactors (PWR). Thus this work aims at providing a new formulation for such a variety of flows. The basic idea consists in using an integral approach that is applied to the governing set of partial differential equations. Here the keystone is the conservative Euler set of equations, including mass, momentum and energy balance for any equation of state.Hence, the first chapter investigates the case of one-dimensional pipes with continuous or discontinuous cross-section. Once the 1D+ integral formulation has been presented, numerical results are compared with : (i) the classical Well-Balanced (WB) approach, and (ii) the reference solution obtained with a multi-dimensional code with huge mesh refinement.The second and third chapters provide some new insight on the numerical modeling of compressible flows in domains obstructed with many tubes. The integral formulation is derived, and numerical schemes are detailed, in order to handle fluid/fluid interfaces and wall boundaries. Schemes may be explicit (chapter 2), or implicit (chapter 3). A few analytic test cases are investigated. Focus is made on the flow incoming a region containing many tiny and aligned tubes. Here again, a comparison with the reference "fluid" solution is achieved; results are also compared with those arising from the WB approach, and with those coming from the 1D+ integral approach proposed in the first chapter
Salemi, Bamdad. "Contributions expérimentales sur les écoulements diphasiques dans un évaporateur de climatisation : essais en eau-air et en réfrigérant R134a". Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0282/document.
Understanding of multiphase flows in mini-channel evaporators is essential for the performance of air-conditioning systems, particularly in automotive sector. This thesis is mainly interested in behavior of inlet flow and phase distribution in the mini-channels. Initially, an adiabatic two-phase flow at the evaporator's inlet was studied. A transparent experimental apparatus with the same geometry as an evaporator's inlet has been designed. This test section helped us to reproduce the same flow regimes with air-water as flow regimes encountered with R134a in an evaporator. Several characterization techniques were used (visualization, conductance probes, Pitot tube and pressure taps) to determine pressure losses, liquid film thickness and gas velocity in a predominantly annular flow regime. Following the same principle, another experimental facility in stainless steel was developed to directly characterize the R134a flow at the evaporator's inlet. Finally, we have extended the study to the case of a compact evaporator in two adiabatic situations: single-phase (water) and two-phase (air-water). Pressure losses, phase distribution along the evaporator and flow regime in mini-channels were studied on an evaporator made of transparent materials (polycarbonate) with a close geometry to that of a real evaporator. Numerous results were obtained to provide a consistent database that would be useful for numerical simulation of this type of two-phase flows
Valle, Medina Maria Elena. "Modélisation des décanteurs secondaires : étude en mécanique des fluides numériques de la dynamique de la sédimentation des boues activées". Thesis, Strasbourg, 2019. https://publication-theses.unistra.fr/public/theses_doctorat/2019/VALLEMEDINA_MariaElena_2019_ED269.pdf.
The conventional activated sludge process is the most widely used process for treating urban wastewater. Biomass (activated sludge) grows and forms biological flocs that must be separated from the treated water. This is usually performed by gravity in a clarifier. Activated sludge particles are subject to different settling processes, depending on their properties. Clarifier simulation is probably the most developed field of application for computational fluid dynamics applied to wastewater treatment. However, all sedimentation mechanisms are not always fully represented. This work began by adding the compression mechanism as a second-order term in the partial differential equation describing sludge sedimentation. The parameters of the modified model were identified based on experimental data from a closed system. Then, simulations of a full-scale clarifier allowed the model to be validated based on the measured sludge blanket height and particle velocity profiles. Small treatment plants are characterized by very dynamic inlet conditions (flow variations, on/off cycles). Thus, the validated model was used to simulate these operating conditions
El proceso de lodos activados convencional para el tratamiento del agua residual es el más usado para remover los contaminantes del agua residual urbana. La biomasa (lodo activado) crece y forma flocs biológicos que deben ser separados del agua tratada. Normalmente esta acción se realiza por medio de la gravedad en un sedimentador. Las partículas de lodo activado pueden someterse a diferentes comportamientos de sedimentación dependiendo de sus propiedades. La simulación de los clarificadores secundarios es probablemente el área más desarrollada para la aplicación de la mecánica de fluidos computacional en el tratamiento del agua residual. Sin embargo, no todos los mecanismos de sedimentación están siempre representados en un modelo. Este trabajo presenta la adición de la compresión como un término de segundo orden en una ecuación diferencial parcial que describe la sedimentación del lodo. La identificación de los parámetros del modelo se realizó a través de experimentos realizados en un sistema cerrado. Luego, simulaciones en un clarificador a escala real permitieron validar el modelo basándose en la medición de la altura del manto de lodos y los perfiles de velocidad de las partículas. Estaciones depurados de pequeña capacidad se caracterizan por una dinámica discontinua de las condiciones de entrada (variaciones en el caudal, ciclos de encendido/apagado). Así el modelo validado se usó para simular estas condiciones operacionales
Luna, Valencia Juan Esteban. "Étude du refroidissement d'un assemblage combustible par un écoulement vertical vapeur/gouttes à l'échelle d'un sous-canal". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0041.
During a Loss of Coolant Accident (LOCA), an increase in fuel temperature and a drop in core pressure can occur and eventually lead to significant deformation or even rupture of the fuel rod cladding. Consequently, the effectiveness of the safety systems can be compromised. Understanding all these phenomena is an important safety issue, which is why IRSN is developing the DRACCAR software, the aim of which is to reproduce all the mechanical, chemical and thermal-hydraulic phenomena of a LOCA.Simulation tools such as DRACCAR need to be compared with experimental results. It is in this context that the present thesis was written. From a thermal-hydraulic point of view, it is essential that DRACCAR can accurately simulate the different heat transfer mechanisms occurring in a sub-channel of an assembly. The aim of this thesis is to contribute to the improvement of DRACCAR models and to the validation of the software. For this purpose, experimental tests are carried out on the COLIBRI loop, allowing to reproduce the characteristic fluid flow of a PRCA in a partially plugged sub-channel and the wall/fluid exchanges taking place there. This setup, developed in a previous thesis (Peña Carillo, 2018), is associated with software (NECTAR) dedicated to the modeling of coupled heat and mass transfer phenomena, as well as drop dynamics in the COLIBRI test section. This software allows to analyze COLIBRI results but also to test different physical models before eventually integrating them into DRACCAR
Cochard, Thomas. "Injection de tensioactif pour la récupération assistée du pétrole : implication sur les lois régissant les écoulements eau-hydrocarbure-tensioactif en milieu poreux". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066647/document.
The main objective of the PhD is to study experimentally the oil mobilization using surfactant in a porous media below the residual oil saturation. At the residual oil saturation, the oil network is disconnected and organized in ganglia of different sizes and shapes all along the sample. This residual oil is difficult to produce in the classical conditions of water flooding because of capillary trapping created by the interfacial tension between oil and water. Injection of surfactant is able to mobilize the remaining oil at flow rates consistent with the real case of an oil mature reservoir. The use of surfactant allows lowering the interfacial tension by several orders of magnitude, towards ultra-low values (10-3 mN/m), strongly decreasing the capillary forces and so, mobilizing the oil. The first main study of the PhD work was to characterize the displacement of the surfactant injected in a sandstone sample in monophasic conditions (without oil). Breakthrough curves have been analyzed in term of dispersivity and adsorption. Experiments have shown that a better way to model the surfactant transport is to use a Langmuir kinetic adsorption model. For the diphasic case, we have developed a microfluidic 2D system with a random pore geometry of controlled conditions. The experiments are based on the injection of a small ganglia through a central channel, then, a surfactant flood is generated. The aim is to see how ganglia are displaced within the micromodel. New mechanisms have been identified and a way to model those phenomena has been proposed. A better understanding of surfactant and oil transport in porous media is key for chemical enhanced oil recovery processes
Jules, Valentin. "Écoulement dans un aquifère non confiné profond alimenté par la pluie". Thesis, Université de Paris (2019-....), 2020. http://www.theses.fr/2020UNIP7074.
During a rain event, water infiltrates into the ground where it flows slowly towards a river. The time scale and the geometry of this flow control the chemical composition and the discharge of the river. We use a tank filled with glass beads to simulate this process in a simplified laboratory experiment. A sprinkler pipe generates rain, which infiltrates into the porous material. Groundwater exits this laboratory aquifer througha side of the tank. Guérin et al. (2014) investigated the case of a quasi-horizontal flow. In nature, however, groundwater often follows non-horizontal flowlines. To create a vertical flow, we place the outlet of our experiment high above its bottom. Long after the rain started, in steady state, we can describe the flow in our aquifer with a combination of complex analysis and numerical methods. The distribution of travel times can thus gives informations about the aquifer geometry. More over, we find that, during rainfall, the discharge Q increases as the rainfall rate R times the time t (Q ∝ Rt). This laboratory aquifer thus responds linearly to the forcing. This response give informations about hydrological properties of the aquifer
Defrance, Laure. "Bioréacteur à membrane pour le traitement des eaux résiduaires : étude du colmatage de membranes minérales et amélioration du flux de perméat par application de techniques hydrodynamiques". Compiègne, 1997. http://www.theses.fr/1997COMP1055.
Pollet, Ingrid. "Simulation numérique de la contamination de la nappe par le perchloroéthylène depuis un site industriel en bordure du piémont alsacien". Université Louis Pasteur (Strasbourg) (1971-2008), 2004. https://publication-theses.unistra.fr/restreint/theses_doctorat/2004/POLLET_Ingrid_2004.pdf.
A hydrodynamic model of the contaminated aquifer was built to study the groundwater contamination by percholoroethylen in the south west of Strasbourg. The studied domain stretches from piedmont to plain and covers an area of several hundreds of hectares. A relation between fluctuations of hydraulic conditions and piezometric levels was established to reproduce the groundwater behaviour in transient time. Then, dissolved pollutant transport was modelled with one-phase transport numerical model using velocities determined before. Simulations pointed out the influence of hydrodynamic properties of media and of boundaries conditions on the evolution of the dissolved plume. Otherwise, it seems the media description to be refined, particularly by considering a media more heterogeneous and by modelling dissolution of the pollutant in aqueous phase. A several-phases transport numerical model was also used to localise more precisely the pollutant phase in order to reproduce the percholoroethylen concentrations observed. This step is based on an analytical study realised to determine the vertical distribution of residual pollutant from concentrations and velocities profiles measured near the supposed source. This study ends in several heterogeneous sources trapped in the less permeable zones increasing considerably the treatment duration
Meyer, Nadège. "Simulation numérique de la viscosité de liquides : effets des paramètres d'interaction, de la température et de la pression sous conditions ambiantes et extrêmes". Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0293/document.
This work is devoted to the study of the shear viscosity by numerical simulation of equilibrium classical molecular dynamics with a particular attention to the influence of high pressures on this property. From trajectories generated by these simulations and using the Grenn-Kubo formula, the viscosity is obtained. A broad range of systems has been studied, covering from pure atomic fluids to a molecular liquid, as well as binary mixtures. First, we focused on alkali metals. The main outcome of this study is that the viscosity of these metals has a universal behavior over a wide range of phase diagram. Furthermore, over this interval, the universal relation that we have proposed permits the prediction of the viscosity value of any elements with an uncertainty lower than 10%. The validity of the Stokes-Einstein relation, connecting the self-diffusion coefficient and the viscosity, has also been verified. Then, a systematic study has been carried out on model mixtures of Lennard-Jones fluids to test the influence of interaction parameters on the viscosity behavior. A theoretical estimation based on the effective one-component fluid model has been proposed. Moreover, the Stokes-Einstein relation has been successfully extended to mixtures. These observations have been compared with two real alloys: K-Cs and Li-Bi. Lastly, a preliminary study on water has been undertaken by modeling the interactions with two models: SPC/E, non-polarizable and BK3, polarizable. The effect of the introduction of the polarizability on the viscosity has been studied. The validity of Stokes-Einstein and Stokes-Einstein-Debye, involving the rotation of the molecule, has been evaluated under very high pressure
Kositsakulchai͏̈, Ekasit. "Modélisation de la dynamique de l'hydrosystème du bassin du Mae Klong (Thai͏̈lande). Une esquisse de système interactif d'aide à la décision pour la gestion de l'eau". Montpellier 2, 2001. http://www.theses.fr/2001MON20008.
David, Lucas. "Sodium-water reaction : a heterogeneous runaway process". Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0580.
The reaction of sodium metal with water is a heterogeneous reaction: reactants are in two distinct condensed phases, separated by a layer of gas. In such configuration, a runaway of the reaction is theoretically not possible, yet experimental observations show the opposite. An explosive runaway of sodium-water reaction can indeed be triggered, generating pressure waves and ejecting matter. A mechanism is proposed to explain these observations by sodium vaporization. As a consequence of the heat generated by the heterogeneous reaction, sodium would vaporize intensely and mix with water vapor in gas-phase, which would generate a homogeneous configuration enabling a runaway. The study of this mechanism is presented through a three-way approach: analytical, numerical and experimental. An analytical, Semenov-type 0d model, adapted to the heterogeneous configuration, first demonstrates that this mechanism can result in a reaction runaway. Numerical simulations of sodium-water reaction, in 1d and in 2d with the “diffuse-interface” approach, then show that this mechanism can produce explosive effects such as shock waves and ejection of matter. Finally, an experimental study confirms the presence of sodium vapor, although the temperature measured inside the liquid sodium is far from its boiling temperature. This study therefore shows that the explosive effects of the sodium-water reaction can theoretically be explained by a rapid vaporization of sodium, although as experimental results suggest, the actual phenomenology is probably more complex. It possibly involves subscale phenomena such as turbulence or fragmentation mechanisms that were not considered in this study
Ganfoud, Nidhal. "Simulation moléculaire d'électrolytes aqueux dans les carbones nanoporeux : énergie bleue et désalinisation de l'eau". Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS108.
When fresh river water mixes with salty sea water, a large amount of energy is lost. Conversely, the desalination of seawater for the production of drinking water requires very large amounts of energy. A new approach has been proposed in 2009 to harvest this "blue energy", thanks to the charge/discharge of electrodes in electrolytes with high/low salt concentration. The use of nanoporous carbon electrodes seems promising, but the traditional models (such as Poisson-Boltzmann) used to determine the relevant quantities do not apply in this case where molecular interactions play an essential role. We overcome this difficulty by performing molecular dynamics simulations of nanoporous carbon electrodes in the presence of an aqueous electrolyte. We evaluate the electrical capacity and the amount of ions adsorbed inside the electrodes as a function of the electrolyte composition and its concentration. In addition, these simulations allow us to understand the microscopic mechanisms leading to the storage of the charge, the effect of the structure of the carbon electrode, the salt concentration in the electrolyte and the chemical nature of the salt
Bohy, Martine. "Caractérisation de sources de pollution composées d'un mélange de solvants chlorés en aquifère alluvial : Expérimentations en laboratoire et sur site contrôlé associées à la simulation numérique". Université Louis Pasteur (Strasbourg) (1971-2008), 2003. https://publication-theses.unistra.fr/public/theses_doctorat/2003/BOHY_Martine_2003.pdf.
Two large-scale experiments were conducted on the controlled site SCERES to study the transport of a mixture of two chlorinated solvents in the saturated and unsaturated zones of the sandy aquifer and to quantify the mass transfers across the capillary fringe and towards the atmosphere or to the groundwater. The experiments involved an injection of trichloroethylene (TCE) and perchloroethylene (PCE) in SCERES, under controlled conditions, with multidepth sampling of gas in the unsaturated zone and water in the capillary zone and the groundwater. The mass transfer of TCE and PCE vapors from the vadose zone to the atmosphere was quantified using a vertical flux chamber and calculated with a semi-experimental method. The multiphase multicomponent code SIMUSCOPP was used in order to simulate the vapor transport in the unsaturated zone of the artificial aquifer environment. The calculated vapor concentrations were in good agreement with those observed. The obtained results point out that vertical dispersion of chlorinated solvent vapors across the capillary fringe can cause a significant groundwater pollution in spite of the slowness of the aqueous diffusion process. The study of the partitioning tracer method for quantification and location of TCE sources in the saturated zone of the aquifer constitutes the second part of this work. As the transposition of the method from laboratory columns to the experimental site failed, we decided to realize several complementary column-tests to determine the role of the volume of pollutant, its repartition in the porous medium, the presence of heterogeneities and the influence of the contact time of the tracers with the organic phase. We could thus show a partitioning kinetics of the reactive tracer
Mercier, Matthieu. "Etude expérimentale de la génération de structures linéaires et non-linéaires (solibores, solitons) en milieu stratifié". Lyon, Ecole normale supérieure, 2010. http://www.theses.fr/2010ENSL0574.
Our experimental approach models interactions of internal waves with topographies or background stratification. Signal processing of experimental data such as complex demodulation has also been developed. Different types of internal waves have been generated, thanks to the characterization and control of a new wave maker. Internal plane waves reflecting on slopes have been studied to verify the absence of back-reflected waves near critical reflection. The interaction of a vertical mode with a large topography have revealed the importance of sub-critical slopes and of the height of the topography on the conversion of the incident mode. We have realized the first experimental generation of nonlinear wave trains (solitons) by internal wave beams impinging on a pycnocline. Finally, the study of the coupled dynamics of a boat with the surrounding stratified fluid have shown that the « dead water » regime is solely defined by the Froude number associated to the stratification considered
Arvengas, Arnaud. "Cavitation acoustique dans l'eau et quelques liquides organiques : densité et limite de rupture". Phd thesis, Université Paris-Diderot - Paris VII, 2011. http://tel.archives-ouvertes.fr/tel-00710980.
Marty, Aurélie. "Formation de panaches bactériens lors de la filtration à travers des microsystèmes". Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1570/.
The operation of filtration units, such as those used in the production of drinking water, can be altered by the uncontrolled presence of bacteria. Bacterial adhesion and biofilm formation are complex processes influenced by factors (hydrodynamic, physico-chemical, microbiological, etc. ). The aim of this thesis was to make progress in the understanding of bacterial transfer during flow through a porous medium. Microfluidic devices made of polydimethylsiloxane with controlled geometries mimicking filtration systems were developed to follow, by optical microscopy, the adhesion dynamics. Experimental results, in non-nutritive conditions, show that Escherichia coli and other Gram- bacteria (Pseudomonas aeruginosa) or Gram+ bacteria (Enterococcus hirae, Staphylococcus aureus), accumulate as streamers in the downstream a zone of the microchannels and that streamers are promoted by medium's porous tortuosity. In parallel, a numerical flow study highlighted a link between streamer formation and the presence of secondary flow at the inlet and the outlet of the microchannels. From the numerical flow simulations and experimental results, a scenario for streamer formation is proposed: i) bacterial transport toward the wall, enhanced by the secondary flow at the microchannel entrance; ii) formation of filaments, driven towards the bulk by secondary flow at the microchannel outlet; iii) capture of bacteria by the filaments ("fishing net" effect) and streamers formation. A fuller understanding of these phenomena should allow better control of bacterial development in filtration processes (e. G. Sand filtration or membrane filtration) or other systems such as water distribution networks
Gauffre, Marie-Charlotte. "Simulation numérique des écoulements diphasiques 3D instationnaires au cours du remplissage d'une maquette expérimentale eau / air du dôme LOX d'un moteur-fusée". Thesis, Toulouse, INPT, 2013. http://www.theses.fr/2013INPT0050.
New generation cryogenic upper-stage rocket engines are planned to be restartable during the orbit mission. The re-ignition of the engine is particularly difficult in space flight conditions. The engine contains a LOX dome fed with liquid oxygen (LOX) supplied by a bushel valve through a pipe. The gas / liquid mixture forming in the dome is injected into the combustion chamber through a number of injectors. Therefore the two-phase flow distribution at injectors outlet carries a real importance in terms of the ignition from the opening to the closing phases of the main valve. These flight conditions are of paramount importance, however, they are truly difficult to reproduce by experimental ground tests. In the framework of these studies, a research program set up by CNES (the French Space Agency) and SAFRAN Snecma, tries to study the LOX dome filling, through experiments and numerical studies. The aim is to identify the phenomena at sake to know the limit conditions at injectors, which will determine the ignition stage in the combustion chamber. Experiments are carried out at LEGI (Geophysical and Industrial Flows Laboratory in Grenoble) with substitution fluids (air and water), without heat and mass transfer on a rocket engine mockup. The work presented here, conducted at IMFT (Fluid Mechanics Institute in Toulouse), intends to reproduce the experimental results using incompressible two-phase flow simulations. The geometry used is representative of the experimental mockup composed of a feeding pipe, a dome, an igniter pipe and injectors. The aim of this study is to demonstrate the feasibility of a 3D unsteady two-phase flow calculation with the industrial code NEPTUNE_CFD, to simulate the LOX dome filling of the rocket engine, by taking into account the real geometry and the preponderant physical phenomena. The comparison of the predictions with the experimental results is carried out in order to estimate the code capability to predict the flow behavior, according to available closure laws. Finally, several sensitivity studies on the closure laws have been conducted to assess their influence on the numerical results. An important work has been carried out to obtain the proper inlet conditions to be imposed in the code in coherence with the experiments. Studies have equally been conducted on an isolated injector
El, Mahi Imad. "Schémas volumes finis pour la simulation numérique de problèmes à fronts raides en maillages non structurés adaptatifs". Rouen, 1999. http://www.theses.fr/1999ROUES019.
Zeru, Allelign. "Numerical investigations on the inversion of pumped concentrations for groundwater pollution quantification". Université Louis Pasteur (Strasbourg) (1971-2008), 2004. https://publication-theses.unistra.fr/public/theses_doctorat/2004/ZERU_Allelign_2004.pdf.
Marcandella, Élise. "Caractérisation biophysicochimique du transfert d'un soluté réactif en milieu poreux saturé : application à la migration du phényl acétate de mercure à travers les sédiments du Rhin". Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL026N.