Дисертації з теми "Écoulements incompressibles diphasiques"
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Amaziane, Brahim. "Application des techniques d'homogénéisation aux écoulements diphasiques incompressibles en milieu poreux." Lyon 1, 1988. http://www.theses.fr/1988LYO10030.
Повний текст джерелаAhmadi-Sénichault, Azita. "Utilisation de propriétés équivalentes dans les modèles de réservoir : cas des écoulements diphasiques incompressibles." Bordeaux 1, 1992. http://www.theses.fr/1992BOR10660.
Повний текст джерелаJasor, Marie-Josée. "Perturbations singulières d'équations non linéaires de diffusion-convection, modèlisant des écoulements diphasiques incompressibles en milieu poreux." Pau, 1992. http://www.theses.fr/1992PAUU3013.
Повний текст джерелаCayré, Florent. "Méthodes volumes finis sur maillages non structurés pour la simulation numérique des écoulements incompressibles monophasiques et diphasiques." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0025/MQ49061.pdf.
Повний текст джерелаTrontin, Pierre. "Développement d'une approche de type LES pour la simulation d'écoulements diphasiques avec interface : application à l'atomisation primaire." Phd thesis, Ecole nationale superieure de l'aeronautique et de l'espace, 2009. http://tel.archives-ouvertes.fr/tel-00499373.
Повний текст джерелаObelembia, Adande Hugo. "Contribution à l'étude de l'unicité pour des systèmes d'équations de conservation : cas des écoulements diphasiques incompressibles en milieu poreux." Pau, 1996. http://www.theses.fr/1996PAUU3025.
Повний текст джерелаDelage, Santacreu Stéphanie. "Méthode de raffinement de maillage adaptatif hybride pour le suivi de fronts dans des écoulements incompressibles." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2006. http://tel.archives-ouvertes.fr/tel-00012193.
Повний текст джерелаla taille mémoire. On montre au travers de cas d'étude 2D et 3D, judicieusement choisis, l'efficacité de cette méthode.
Fanzar, Abdelaziz. "Développement d’un code numérique pour la simulation et l’étude de l’hydrodynamique et de la physico-chimie de milieux diphasiques incompressibles. Cas d’une goutte d’eau dans l’huile de paraffine." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4339.
Повний текст джерелаFor several decades, an important scientific activity has focused on the numerical, theoretical and experimental hydrodynamics of drops. This work presents numerical results of a single droplet in the gravity field and in non-isothermal conditions. The simulation such a multiphase system is important in both academic and industrial world. This is particularly the case in the field of emulsions, wetting problems and evaporation. To achieve this goal, there are still important algorithmic problems due to the free moving interfaces and the description of capillary effects. Here, a Volume of Fluid technique has been implemented with high order temporal and spatial schemes to preserve the sharpness of the drop interface. The system under consideration is a simplified model consisting in a single water droplet in a continuous paraffin oil phase. These liquids are immiscible and non-compressible and the overall evolution is unsteady. Capillary contributions such as temperature and surfactant dependent surface tension are fully accounted for. This presentation is aimed to show the capabilities of VOF techniques for the simulations of unsteady multiphase systems in non-isothermal configurations. The role of the droplet initial position and temperature field is described with good numerical stability. There are still important problems remaining in the simulation of free interface systems with such a technique. Spurious currents induced by the description of capillarity can in particular come into play. But these latter can be controlled once the droplet average velocity due to drainage becomes large enough
Billaud, Friess Marie. "Eléments finis stabilisés pour des écoulements diphasiques compressible-incompressible." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2009. http://tel.archives-ouvertes.fr/tel-00565815.
Повний текст джерелаBillaud, Marie. "Eléments finis stabilisés pour des écoulements diphasiques compressible-incompressible." Thesis, Bordeaux 1, 2009. http://www.theses.fr/2009BOR13872/document.
Повний текст джерелаIn this work, we are interested in the numerical simulation of instationnary viscous flows of two immiscible fluids, separated by a mobile interface. In particular, flows without shock composed of a gas phase and a liquid phase are considered. In order to modelize such flows, an approach in which the gaz is described by compressible Navier-Stokes equations and the liquid by incompressible Navier-Stokes équations is proposed. The coupling between these two models is the originality and the stake of this thesis. To treat this important difficulty, a global (i.e. the same for each phase) and simple method is elaborated. In our procedure we propose, using the Navier-Stokes equations formulated in set of primitives unknowns (pressure, velocity and temperature), to elaborate a strategy that relies on the follow components: the stabilized finite element method to discretize spatially the Navier-Stokes equations; the Level Set method for tracking the interface precisely with a discontinuous Galerkin method to solve the associated transport equation; and some averaged quantities to treat the discontinuities at the interface. The good behaviour of this approach is performed on both one and two spatial dimensions
Sherif, Ahmed. "Compact High-Order Accurate Scheme for Laminar Incompressible Two-Phase Flows." Electronic Thesis or Diss., Ecole centrale de Nantes, 2023. http://www.theses.fr/2023ECDN0004.
Повний текст джерелаThe objective of this thesis is to develop a high-order accurate method to solve the two-phase incompressible laminar flowproblem. Three main tasks are to be achieved. First, the method has to be energy-stable meaning that the divergence-free condition of the incompressible Navier-Stokes equation is satisfied everywhere in the computational domain. Second, the local discontinuities arising in the two-phase flow field have to be captured accurately. Third, the material interface betweenthe two fluids has to be represented accurately in each time step. In this work, a novel Hybridizable Discontinuous Galerkin (HDG) method is used for the spatial discretization. This hybrid method that belongs to the family of DG-FEM methods satisfies the divergence-free condition by introducing velocity and pressure trace variables of the same order plus a tailoredvelocity and pressure approximation inside the elements. Furthermore, the concepts of eXtended FEM (X-FEM) are used toapproximate discontinuities in the flow field by enriching the standard FEM approximation in elements where two fluids exist. Finally, the moving material interface between the twofluids is captured using the Level-Set method
Vincent, Stéphane. "Modélisation d'écoulements incompressibles de fluides non-miscibles." Bordeaux 1, 1999. http://www.theses.fr/1999BOR10648.
Повний текст джерелаMichel, Anthony. "Convergence de schémas volumes finis pour des problèmes de convection diffusion non linéaires." Phd thesis, Université de Provence - Aix-Marseille I, 2001. http://tel.archives-ouvertes.fr/tel-00002553.
Повний текст джерелаNasser, El Dine Houssein. "Étude mathématique et numérique pour le modèle Darcy-Brinkman pour les écoulements diphasiques en milieu poreux." Thesis, Ecole centrale de Nantes, 2017. http://www.theses.fr/2017ECDN0022.
Повний текст джерелаThe system modeling a two incompressible phase flow with high porosity in an oil-field is governed by the law of Darcy-Brinkman. The velocity of filtration of Darcy leads to an elliptic equation in pressure and a degenerate parabolic equation in saturation. This system is widely used in porous media. In this thesis, we are interested in the modification of Brinkman which consists in modifying Darcy’s law by adding a viscosity disspative term. This system leads to an elliptic equation in pressure and unstandard parabolic equation in saturation regularized in time. First, we are interested in the mathematical study of the Darcy-Brinkman’s system and in the regularity of the solutions. To simulate numerically the solutions of this problem, we study the convergence of a finite-volume scheme on an admissible mesh for a homogeneous porous media. Then, we propose a combined method of finite volume - nonconforming finite element type to deal with the anisotropic of the media. In the second part of this thesis we deal with the compressibility of the fluids. We suggest a model of Darcy- Brinkman to describe the compressible monophasic case. We show that this model is well posed in dimension one in the whole space. Then, under the hypothesis of Bear, we also show that this model is well posed in dimension d ≥ 2
Larocque, Jérôme. "Modélisation et simulation numérique d’écoulements incompressibles turbulents diphasiques à phases non miscibles : application à l’interaction d’un jet turbulent avec une surface libre dans une cavité." Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13628/document.
Повний текст джерелаThe scope of this dissertation is to model and simulate non-miscible two-phase turbulent and incompressible flows. The modeling and the simulation of this kind of flows are carried out in the framework of the Large Eddy Simulation (LES) which consists in calculating directly the largest structures of the flow and in modeling the finest ones. These numerical methods, applied usually to the simulation of single-phase turbulent flows, are extended to the simulation of two-phase turbulent flows in this work. Hence, the LES methods are coupled with an Eulerian ’Volume of Fluid’ (VOF) approach which is particularly adapted to interfacial flows. The relevance of this numerical coupling bewtween LES and VOF methods is validated in the following industrial configuration of the CEA-CESTA: the impact of a turbulent round jet on a free water/air surface in a cavity. Some experimental velocity measurements (Particle Image Velocimetry PIV), carried out at the CEA-CESTA, are available to validate the numerical results
Lesage, Anne-Cécile. "Méthodes Level Set pour les écoulements bi-fluides incompressibles avec tension de surface et angle de contact sur maillages non-structurés." Nice, 2006. http://www.theses.fr/2006NICE4047.
Повний текст джерелаDjati, Nabil. "Study of interface capturing methods for two-phase flows." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI052/document.
Повний текст джерелаThis thesis is devoted to the development and comparison of interface methods for incompressible two-phase flows. It focuses on the selection of robust interface capturing methods, then on the manner of their coupling with the Navier-stokes solver. The level-set method is first investigated, in particular the influence of the advection scheme and the reinitialization step on the accuracy of the interface capturing. It is shown that the volume constraint method for reinitialization is robust and accurate in combination with the conservative fifth-order WENO schemes for the advection. It is found that interface errors increase drastically when the CFL number is very small. As a remedy, reinitializing the level-set field less often reduces the amount of numerical diffusion and non-physical interface displacement. Mass conservation is, however, not guaranteed with the level-set methods. The volume-of-fluid (VOF) method is then investigated, which naturally conserves the mass of the reference fluid. A geometrical consistent and conservative scheme is adopted, then an alternative technique more easily extended to 3D. It is found that both methods give very similar results. The moment-of-fluid (MOF) method, which reconstructs the interface using the reference fluid centroid, is found to be more accurate than the VOF methods. Different coupled level-set and VOF methods are then investigated, namely: CLSVOF, MCLS, VOSET and CLSMOF. It is observed that the level-set method tends to thicken thin filaments, whereas the VOF and coupled methods break up thin structures in small fluid particles. Finally, we coupled the level-set and volume-of-fluid methods with the incompressible Navier-Stokes solver. We compared different manners (sharp and smoothed) of treating the interface jump conditions. It is shown that the VOF methods are more robust, and provide excellent results for almost all the performed simulations. Two level-set methods are also identified that give very good results, comparable to those obtained with the VOF methods
Vaudor, Geoffroy. "Atomisation assistée par un cisaillement de l'écoulement gazeux. Développement et validation." Rouen, 2015. http://www.theses.fr/2015ROUES024.
Повний текст джерелаAssisted atomization enables to transform a liquid jet into drops using a co-flowing high-speed gas jet. This method is applied in cryogenic engines and aircraft propulsion systems. However, numerical study of these configurations is challenging, due to the high shearing associated with the high density ratio between the liquid and gaseous phases, which make most solvers unstable, including the ARCHER solver developed in CORIA laboratory. Numerical developments on the modeling of the convective term based on Rudman's work have been performed. The main idea is to re-establish the consistency between numerical mass and momentum transport. The original discretization requires moving the interface onto a dual grid. This method has proved to be stable but numerically costly. A new discretization which enables to get rid of the second grid is suggested and validated on different test cases. Experimental studies on assisted atomization have been carried out in LEGI laboratory for years and the new numerical scheme developed during these studies have enabled to simulate numerically a 2D sheared liquid film and a coaxial liquid jet in 3D, which have then been compared to the experimental results
Zhang, Xin. "Étude qualitative des solutions du système de Navier-Stokes incompressible à densité variable." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1215/document.
Повний текст джерелаThis thesis is dedicated to two different problems in the mathematical study of the viscous incompressible fluids: the persistence of tangential regularity and the motion of a free surface.The first problem concerns the study of the qualitative properties of some thermodynamical quantities in incompressible fluid models, such as the temperature for Boussinesq system with no diffusion and the density for the non-homogeneous Navier-Stokes system. Typically, we assume those two quantities to be initially piecewise constant along an interface with H"older regularity.As a consequence of stability of certain directional smoothness of the velocity field, we establish that the regularity of the interfaces persist globally with respect to time both in the two dimensional and higher dimensional cases (under some smallness condition). Our strategy is borrowed from the pioneering works by J.-Y.Chemin in 1990s on the vortex patch problem for ideal fluids.Let us emphasize that, apart from the directional regularity, we only impose rough (critical) regularity on the velocity field. The proof requires tools from para-differential calculus and multiplier space theory.In the last part of this thesis, we are concerned with the free boundary value problem for two-phase density-dependent Navier-Stokes system.This model is used to describe the motion of two immiscible liquids, like the oil and the water. Such mixture may occur in different situations, such as in a fixed bounded container, in a moving bounded droplet or in a river with finite depth. We establish the short time well-posedness for this problem. Our result strongly relies on the $L_p$-$L_q$ maximal regularity theoryfor parabolic equations
Ottino, Gabriele. "Two approaches to the study of detached flows." Thesis, Bordeaux 1, 2009. http://www.theses.fr/2009BOR13786/document.
Повний текст джерелаIn the present work flow separation phenomena are investigated by means of two different approaches. In the first part, 2D unsteady incompressible inviscid flows are studied. An analytical-numerical model, based on the conjunction of a conformal mapping and a point vortex method, is built to define the potential flow field in a doubly connected domain where bodies are characterized by a variation in time of their circulation. In particular, the study of the unsteady flow past a 2-blade Darrieus VAWT is addressed. Until now the study of vortex motions has only been described in doubly-connected flow fields where the circulations have a constant null value. The flow field here analysed has a deep unsteadiness, which determines the circulations varying in time: so a technique is developed to uniquely define the circulations around the bodies. Three conditions result necessary to be imposed: in addition to the two Kutta conditions at the trailing edges, another one has to be imposed in order to respect the Kelvin theorem. With a classical configuration, this machine, experiencing angles of attack of opposite values, gives rise to complex vortex shedding phenomena that reduce its performances and stress its structure. In order to control the flow separation from the blades, an innovative solution is qualitatively investigated which consists of taking blade profiles provided with vortex trapping cavities. Interesting results are obtained, even if in the limit of inviscid flow. In the second part compressible viscous flows are taken into account. A fully Navier-Stokes equations solver is implemented introducing the penalization technique. The idea is to replace the bodies by the fluid, in a way that also into the bodies the penalized Navier-Stokes equations remain valid, respecting the boundary conditions on their contours. Starting from this purpose, the bodies are considered as porous media with a little porosity with respect to that of the external flow, which tends to infinity. This technique allows simple Cartesian meshes to be used, also for very complex geometries like those of industrial interest. The resulting code is tested on different flow fields, both steady and unsteady, both subsonic and supersonic, obtaining always a good agreement with other theoretical and numerical results described in literature
Ahmed, Aqeel. "LES of atomization and cavitation for fuel injectors." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR048/document.
Повний текст джерелаThis thesis presents Large Eddy Simulation (LES) of fuel injection, atomization and cavitation inside the fuel injector for applications related to internal combustion engines. For atomization modeling, Eulerian Lagrangian Spray Atomization (ELSA) model is used. The model solves for volume fraction of liquid fuel as well as liquid-gas interface surface density to describe the complete atomization process. In this thesis, flow inside the injector is also considered for subsequent study of atomization. The study presents the application of ELSA model to a typical diesel injector, both in the context of RANS and LES. The model is validated with the help of experimental data available from Engine Combustion Network (ECN). The ELSA model which is normally designed for diffused (unresolved) interfaces, where the exact location of the liquid-gas interface is not considered, is extended to work with Volume of Fluid (VOF) type formulation of two phase flow, where interface is explicitly resolved. The coupling is achieved with the help of Interface Resolution Quality (IRQ) criteria, that takes into account both the interface curvature and modeled amount of interface surface. ELSA model is developed first considering both phases as incompressible, the extension to compressible phase is also briefly studied in this thesis, resulting in compressible ELSA formulation that takes into account varying density in each phase. In collaboration with Imperial College London, the Probability Density Function (PDF) formulation with Stochastic Fields is also explored to study atomization. In modern fuel injection systems, quite oftenthe local pressure inside the injector falls below the vapor saturation pressure of the fuel, resulting in cavitation. Cavitation effects the external flow and spray formulation. Thus, a procedure is required to study the phase change as well as jet formulation using a single and consistent numerical setup. A method is developed in this thesis that couples the phase change inside the injector to the external jet atomization. This is achieved using the volume of fluid formulation where the interface is considered between liquid and gas; gas consists of both the vapor and non condensible ambient air
Cayré, Florent. "Méthodes volumes finis sur maillages non structurés pour la simulation numérique des écoulements incompressibles monophasiques et diphasiques." Thèse, 1999. http://constellation.uqac.ca/973/1/11965610.pdf.
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