Дисертації з теми "Simulations Euler-Lagrange"
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Senoner, Jean-Mathieu. "Simulations aux grandes échelles de l’écoulement diphasique dans un brûleur aéronautique par une approche Euler-Lagrange." Thesis, Toulouse, INPT, 2010. http://www.theses.fr/2010INPT0024/document.
Aeroautical gas turbines need to satisfy growingly stringent demands on pollutant emission. Pollutant emissions are directly related to the quality of fuel air mixing prior to combustion. Therefore, their reduction relies on a more accurate prediction of spray formation and interaction of the spray with the gaseous turbulent flowfield. Large-Eddy Simulation (LES) seems an adequate numerical tool to predict these mechanisms. The objective of this thesis is to evaluate the impact of simplified injection methods on the LES of the evaporating two-phase flow inside a complex geometry. The chosen target configuration is an aeronautical combustor installed on the MERCATO test-rig. The experimental setup includes an air-swirler injection system and a pressureswirl atomizer typical of realistic aeronautic combustors. In a first step, a simplified injection model for pressure swirl atomizers neglecting the impact of liquid disintegration on spray dynamics is presented. The main objective of this model lies in the reproduction of similar injection conditions for Eulerian and Lagrangian representations of the dispersed phase. In a second step, the Lagrangian injection method is combined to a secondary breakup model of the literature to partly account for the liquid disintegration process. The presented LES’s of the evaporating two-phase flow inside the MERCATO geometry consider two different aspects. First, the impact of injection modeling on spray dynamics is assessed. Second, Euler-Euler and Euler-Lagrange simulations relying on the common simplified injection model are compared
Hannebique, Grégory. "Etude de la structure des flammes diphasiques dans les brûleurs aéronautiques." Thesis, Toulouse, INPT, 2013. http://www.theses.fr/2013INPT0026/document.
Regulations on pollutants have led to the creation of new combustion systems. Giving that fuel is stored in a liquid form, its evolution until combustion is complex. The ability of Large Eddy Simulation has been demonstrated on academic cases, as well as on industrial configurations, by taking into account the multi-physics phenomena, but there is a lack of studies about two-phase flow flame structures. Two solvers for the simulation of two-phase flows are available in the AVBP code, hence both simulations are performed to compare and increase understanding of the phenomena involved such as dispersion, evaporation and combustion. The first part of the study focuses on the validation of the FIM-UR injection model. This model is able to build velocity and droplet profiles at the injector, without simulating primary and secondary break up. A validation in a turbulent case has already been done, and this study validates the model in a laminar case. Comparisons between monodisperse and polydisperse simulations, and experiments are performed. The monodisperse Lagrangian simulation shows good results but the polydisperse simulation is able to represent profiles in the center of the cone by small droplets and at the peripheral part of the cone, by big ones. Moreover, improvements in the Eulerian model exhibit good results. The next section tries to evaluate the impact of polydispersion. Indeed, when a polydisperse approach is not available, choosing the mean diameter can be tricky. A comparison between the behavior of polydisperse spray and monodisperse sprays ones is realised. Two academic cases are studied: Homogeneous Isotropic Turbulence with particles to analyze the dynamics, and 0D evaporation cases. For the dynamics, preferential concentration, mean drag and reduced mean drag are studied. The latter and preferential concentration are affected by small droplets, and the preferential concentration of a polydisperse spray is equivalent to the average of preferential concentration of classes, extracted from the polydisperse distribution, weighted by the inverse of the Stokes number of each class. The mean drag behaves like the D10 and D20 mean drags. This analysis allows us to choose the D10 to characterize a polydisperse distribution for the dynamics. Zero-D evaporation simulations cannot characterize the polydisperse spray evaporated mass by the evaporated mass of monodisperses sprays. New definitions of diameters from fluidized bed literature enable the use of D50%, which is close to D32. We propose to use this diameter to characterize the evaporation of a polydisperse spray. Finally, the last section studies the structure of two-phase flames in the MERCATO bench, using the Lagrangian formalism, monodisperse and polydisperse but also using the Eulerian formalism. The validation of FIM-UR model and improvements from the first section are used to represent liquid injection conditions. A polydisperse simulation is realized and two monodisperse simulations are computed using mean diameters D10 and D32, thanks to the previous section. Qualitative comparisons and validations are realized, comparing gaseous velocity profiles and liquid velocity profiles. Good agreements are found and the mean diameter D32 seems to be close to the polydisperse spray. A comparison between mean flames is done with an Abel transform of the flame from the experiments. The flame has an "M shape", anchored by small recirculation zones out of the swirler, and by a point at the tip of the central recirculation zone. Then, the impact of droplet distributions is analyzed. Even if few bigger droplets from the polydisperse distribution are convected in the hot gases due to bigger particular time and evaporation time, two-phase flow flame structures are equivalent. Different combustion regimes appeared with premixed flames and pockets of fuel burning in the hot gases
Ali, Abd El Aziz Essa Mohamed. "COUPLED LAGRANGE-EULER MODEL FOR SIMULATION OF BUBBLY FLOW IN VERTICAL PIPES CONSIDERING TURBULENT 3D RANDOM WALKS MODELS AND BUBBLES INTERACTION EFFECTS." Doctoral thesis, Universitat Politècnica de València, 2012. http://hdl.handle.net/10251/18068.
Ali Abd El Aziz Essa ., M. (2012). COUPLED LAGRANGE-EULER MODEL FOR SIMULATION OF BUBBLY FLOW IN VERTICAL PIPES CONSIDERING TURBULENT 3D RANDOM WALKS MODELS AND BUBBLES INTERACTION EFFECTS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/18068
Palancia
Pérard-Lecomte, Aude. "Caractérisation de la dispersion des polluants particulaires dans le sillage des poids lourds en milieu urbain." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0207.
Road transportation is a major contributor to air quality pollution in urban areas, particularly in fine and ultrafine particles. These pollutants are harmful to human health, as they can worsen or cause lung and cardiovascular diseases. In this context, we are interested in the evolution of particles emitted from heavy truck exhausts, starting from their emission. The main objective of this thesis is to study the extent of particle dispersion emitted by heavy truck's exhausts, around and in the wake of heavy trucks. Numerical methods based on an Euler-Lagrange approach were used to simulate and characterize the airflow topology around the truck, using the Reynolds-Averaged Navier-Stokes (RANS) method for the fluid phase and a Lagrangian approach for the dispersed phase. These simulations were supported by wind tunnel measurements in the wake of a reduced-scale model of a heavy truck. Particle Image Velocimetry (PIV) was used for analyzing the air velocity fields, while the dispersion of ultrafine solid particles was characterized by measuring concentration fields using a granulometer. The truck's wake flow is completely detached at the rear of the trailer, revealing a recirculation zone mainly composed of a large vortex, coming from the under-trailer. Particles' dynamics appears to be dominated by turbulence and strongly correlated with vortical structures, especially in the wake of the truck. Indeed, particles tend to concentrate preferentially on the periphery of the main vortex formed behind the truck, as well as in areas of low turbulent intensity. The movement of most inertial particles (diameter > 2.5~mu m) is dominated by gravity, while turbulence is mainly responsible for the movement and deposition of the finest particles (diameter < 2.5~mu m). The position and orientation of the exhaust pipe also have a significant influence on the extent of dispersion and the distribution of particles in the underbody and in the wake of the heavy truck. Indeed, when particles are emitted from the under-trailer, most of them are concentrated in the recirculation zone, less than 1.85H away from the trailer (H being the height of the trailer), and at human height. On the other hand, the particles emitted on the top of the truck are very rarely re-entrained in the recirculation zone, and are mostly concentrated above it, at a height equivalent to 2.6~m (0,9H) above ground level. The exposure of populations to the particles emitted by heavy goods vehicles could therefore be sharply limited when the exhausts are released from top of the truck
Divaret, Lise. "U-RANS Simulation of fluid forces exerted upon an oscillating tube array." Thesis, KTH, Farkost och flyg, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-32747.
Vessiller, Cédric. "Contribution à l'étude des brouillards denses et dilués par la simulation numérique Euler-Euler et Euler-Lagrange." Châtenay-Malabry, Ecole centrale de Paris, 2008. http://www.theses.fr/2008ECAP1112.
The present work particularly focuses on direct injection engines, in which combustion is determined by the characteristics of theatomisation and of the fuel spray produced by the nozzle. Previous experimental and numerical studies show that transition between the dense liquid region at the nozzle exit and the domain where the liquid is dispersed is governed by a range of mechanisms including cavitation inside the injector, aerodynamic instabilities, and turbulence. This report describes the development of an atomisation model for eulerian description of two-phase flows produced by nozzles. The eulerian-eulerian description includes a system of balance equations for each phase:liquid fuel and gas (fuel vapour and air). The amount of interfacial area perunit volume between the gas and the liquid is obtained from a balance equation whose source terms figuring on the rightand side account for production and destruction of interfacial area. A balance equation for the void fraction is used too. Both quantities allow to calculate local spray characteristics from which are deduced interfacial exchange terms between both phases. Various numerical test cases have been carried out to check the numerical implementation of the model while the simulation of droplet laden jets showed the ability of the model to deal with two-phase flows. The model is then validated against experimental results with comparisons of phase penetration in high pressure test cells under conditions close to those prevailing in direct injection diesel engines. Numerical results in evaporating conditions do not follow experimental trends but possibilities to solve the remainaining problems are proposed
Weber, Andreas [Verfasser]. "Simulating bubble movement with the Euler-Lagrange approach / Andreas Weber." München : Verlag Dr. Hut, 2018. http://d-nb.info/117442690X/34.
Wysocki, Stefan. "Joint Euler-Lagrange method for moving surfaces in large-eddy simulation." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/10214.
Hu, Guanghui. "Numerical simulations of the steady Euler equations on unstructured grids." HKBU Institutional Repository, 2009. http://repository.hkbu.edu.hk/etd_ra/1106.
Baraglia, Federico. "Développement d'un modèle triphasique Euler/Euler/Lagrange pour la simulation numérique des écoulements liquide-gaz chargés en particules." Electronic Thesis or Diss., Université de Toulouse (2023-....), 2024. http://www.theses.fr/2024TLSEP017.
This manuscript sums up work carried out during a thesis at the MFEE department of EDF R&D on liquid-gas flows laden with dispersed particles under the supervision of Olivier Simonin (IMFT), Jérôme Laviéville (EDF), and Nicolas Mérigoux (EDF). The thesis aims at providing a working environment for the numerical simulation of two-phase bubbly flows, free-surface flows or in a mixed regime, loaded with particles that can interact with the fluids present in their continuous or dispersed form. These flows can be found in industrial situations such as chemical reactors, power plants, or wastewater treatment plants, as well as in natural situations such as during a flood. The developed tool allows predictions to be made about the performance of these industrial devices or the damage caused by exceptional natural events. The developments are included in the most up-to-date version of neptune_cfd, a multi-fluid solver developed by EDF, CEA, IRSN, and Framatome, based on the standard multi-fluid method that allows the simulation of multiphase flow independently of their typology.The methods implemented are based on well-known two-phase approaches. The stochastic Lagrangian particle tracking method is adapted so that each particle can interact with all the fluids. Closures are proposed to determine the impact of each phase on the behavior of the particles. To verify certain assumptions, a new closure for the Langevin equation on the fluid velocity seen by the particle is proposed. Its behavior is compared to standard models and literature on simple verification cases of homogeneous isotropic turbulence and inhomogeneous cases. The Lagrangian equations obtained are used to close an Eulerian model based on the probability density function approach. The performance of the two developed threephase models is established in terms of particle deposition driven by turbulence or gravity.A significant part of the thesis focuses on an issue that arose during preliminary checks: the phenomenon of air entrainment in plunging jets. Indeed, due to the nature of the solver, bubbles or dispersed droplets can detach from the free-surface depending on the flow conditions. The quantity of these transferred structures and their characteristic size being crucial quantities which drives their behavior, a new model had to be developed. Mass transfer between continuous structures and dispersed inclusions is ensured by the model that describes the evolution of resolved interfaces, the latter was not modified. The one regarding the size of the created bubbles/droplets is integrated into the evolution equation of the interfacial area, a quantity that allows tracking the diameter of the inclusions.All developed models are compared to experimental measurements. The air entrainment model is first tested without the presence of particles in various cases. A hydraulic jump case is also considered to establish the generality of the model. Then, the threephase models are tested in various configurations. First, configurations without air entrainment to isolate the behavior of the particles, and then with air entrainment. The different cases highlighted the importance of certain models and the differences between stochastic Lagrangian and Eulerian methods
Victorino, Silveira Luís. "Simulação numérica da cavitação em turbomáquinas usando uma formulação Euler-Lagrange." Universidade do Estado do Rio de Janeiro, 2014. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=7703.
Turbomáquinas são máquinas operacionais que transferem energia mecânica entre um rotor e um fluido. Estas máquinas têm muitas aplicações industriais. Um dos componentes de uma turbomáquina responsável pela transferência da energia, ou receber a rotação do eixo e transformar em energia de fluido em caso de bomba ou transferir a energia do fluido para o eixo em caso de uma turbina, é o impelidor ou rotor. O fenómeno da cavitação envolve escoamento bifásico: o líquido a ser bombeado e as bolhas de vapor que são formadas durante o processo de bombeamento. O processo de formação dessas bolhas é complexo, mas ocorre principalmente devido a presença de regiões de pressões muito baixas. O colapso dessas bolhas pode muitas vezes levar a deterioração do material, dependendo da intensidade ou da velocidade de colapso das bolhas. O principal objetivo deste trabalho foi estudar o comportamento hidrodinâmico do escoamento nos canais do impelidor de uma turbomáquina do tipo radial usando recursos de fluidodinâmica computacional (CFD). Uma abordagem Euler-Lagrange acoplada com o modelo da equação de Langevin foi empregada para estimar a trajetória das bolhas. Resultados das simulações mostram as particularidades de um escoamento líquido-bolha de vapor passando em um canal de geometria curva, fornecendo assim informações que podem nos ajudar na prevenção da cavitação nessas máquinas.
Turbomachines are operational machines that transfer mechanical energy between a rotor and a fluid. This type of machinery is employed in many industries. One of the main components of a turbomachine responsible for the energy transference, either receiving the rotation of the shaft and transforming it into fluid energy in the case of a pump or transferring energy from the fluid to the shaft in the case of a turbine, is the impeller or rotor. The cavitation phenomenon involves two-phase flow: the liquid to be pumped and the vapor bubbles which are formed during pumping. The formation process of these bubbles is complex, but occurs mainly due to the presence of regions of very low pressure. The collapse of the bubbles can often lead to a deterioration of the material, depending on the intensity or speed of bubbles collapse. The main objectives of this work was to study the hydrodynamic behavior of the flow in the impeller channels of a turbomachine (radial flow turbopump) using computational fluid dynamics (CFD resources). An Euler-Lagrange approach coupled with the Langevin equation model, was employed to estimate the bubbles tracking trajectory. Results of the simulations show the details of liquid-vapor bubble flow in a curved channel, providing insights that help us in the cavitation prevent of this machines.
Lipowsky, Justus Verfasser], Martin [Akademischer Betreuer] Sommerfeld, and Bernd [Akademischer Betreuer] [Platzer. "Zur instationären Euler-Lagrange-Simulation partikelbeladener Drallströmungen / Justus Lipowsky. Betreuer: Martin Sommerfeld ; Bernd Platzer." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2013. http://d-nb.info/1047796384/34.
Paulhiac, Damien. "Modélisation de la combustion d’un spray dans un brûleur aéronautique." Phd thesis, Toulouse, INPT, 2015. http://oatao.univ-toulouse.fr/14495/1/paulhiac_partie_1_sur_2.pdf.
Emans, Maximilian. "Numerische Simulation des unterkühlten Blasensiedens in turbulenter Strömung ein Euler-Lagrange-Verfahren auf orthogonalen Gittern /." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=970212860.
Mathieu, Jean. "Simulation des interactions fluide-structure en théorie des grands déplacements." Paris 11, 1985. http://www.theses.fr/1985PA112362.
An arbitrary Lagrange Euler (ALE) formulation is used to construct a method for solving the transient equations of motion of a coupled fluid structure system with free surface. A variational formulation including the incompressibility condition for fluid in a weak form is retained, so that the coupling conditions are naturally treated. This leads to a spatial discretization method using finite elements coherent in the whole system. The velocities are advanced in time by an explicit scheme while the hydrostatic pression is computed by inversion of a square matrix. A subcycling process permits a reduction of computing time when the structural stability criterion is too restrictive. Numerical results are then discussed
Hoppe, Felix [Verfasser]. "Euler-Lagrange Simulationen von turbulenten, blasenbeladenen Strömungen unter Berücksichtigung von Koaleszenz und Aufbrechen / Felix Hoppe." Hamburg : Helmut-Schmidt-Universität, Bibliothek, 2020. http://d-nb.info/1205078312/34.
Hagan, Daniel S. "Large Eddy Simulation of Oscillatory Flow over a Mobile Rippled Bed using an Euler-Lagrange Approach." ScholarWorks @ UVM, 2018. https://scholarworks.uvm.edu/graddis/848.
Hervo, Loïc. "Simulation numérique de l’écoulement d’un mélange air et phase dispersée pour l’allumage d’une chambre de combustion aéronautique via un formalisme Euler Lagrange." Thesis, Toulouse, ISAE, 2017. http://www.theses.fr/2017ESAE0043/document.
The goal of this thesis is to contribute to the development and validation of numerical tools for the Large Eddy Simulation (LES) of the ignition of a turbulent multiphase flow in a combustion chamber. An energy deposition method that models the energy supplied by the spark plug to the flow was implemented in the CEDRE code. This method was validated on a simulation of the ignition of a purely gaseous laminar propane-air flow. Then, a LES of the non-reacting gas flow in the monosector combustor MERCATO was performed with the Navier-Stokes solver CHARME of the CEDRE code. The comparison between simulations and experiments demonstrates that the main flow field features are well reproduced. In order to simulate the non-reacting dispersed two-phase flow of the same configuration, a simplified injection method called FIMUR was implemented in the Lagrangian solver SPARTE of the CEDRE code. In this method, droplets are injected directly at the tip of the injector with velocities deduced from experimental correlations while the size distribution is directly obtained from experimental data. The comparison of the mean droplet velocity and diameter fields in the vicinity of the injector between simulations and experiments appears satisfactory. Finally, LES's of the ignition of the MERCATO were performed using the non-reacting two-phase flow simulations and the aformentioned energy deposition method. Depending on the instant of energy deposition, the simulations lead to successful or failed ignitions. The flame propagation in a successful ignition was analysed in order to attempt to determine the physical phenomena at play and to better understand them
Feng, Aichun. "Numerical simulation of nonlinear wave-body problem based on desingularized Rankine source and mixed Euler-Lagrange method." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/366540/.
García, Martinez Marta. "Development and validation of the Euler-Lagrange formulation on a parallel and unstructured solver for large-eddy simulation." Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT006H/document.
Particle-laden flows occur in industrial applications ranging from droplets in gas turbines tofluidized bed in chemical industry. Prediction of the dispersed phase properties such as concentration and dynamics are crucial for the design of more efficient devices that meet the new pollutant regulations of the European community. The objective of this thesis is to develop an Euler-Lagrange formulation on a parallel and unstructured solver for large- eddy simulation. This work is motivated by the rapid increase in computing power which opens a new way for simulations that were prohibitive one decade ago. Special attention is taken to keep data structure simplicity and code portability. Developments are validated in two configurations : an academic test of a decaying homogeneous isotropic turbulence and a polydisperse two-phase flow of a confined bluff body. The use of load-balancing capabilities is highlighted as a promising solut! ion in Lagrangian two-phase flow simulations to improve performance when strong imbalance of the dispersed phase is present
Chouippe, Agathe. "Étude numérique de la réduction de traînée par injection de bulles en écoulement de Taylor-Couette." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0052/document.
The study deals with drag reduction induced by bubble injection, its application concerns naval transport. The aim of the study is to shed more light on mechanisms that are involved in this wall friction reduction. The study is based on a numerical approach, and use the JADIM code with an Euler-Lagrange approach: the continuous phase is solved by Direct Numerical Simulation, and the disperse phase by a tracking of each bubble. Within the framework of this study we consider the Taylor-Couette flow configuration (flow between two concentric cylinders in rotation). The first part of the study deals with the modification of the numerical tool, in order to take into account the influence of the disperse phase on the continuous one through forcing terms in the mass and momentum balance equations. The aim of the second part is to study de Taylor-Couette flow in its monophasic configuration, for the purpose of providing a reference of the undisturbed flow. The third part deals with the passive dispersion of bubble in Taylor-Couette flow, in order to analyze the migration mechanisms involved. And the aim of the last part is to study the effects of the disperse phase on the continuous one, by analyzing the influence of bubbly phase parameters (like void fraction and buoyancy)
Schümichen, Michel, Frank Rüdiger, Jochen Fröhlich, and Jürgen Weber. "Simulation of the cavitating flow in a model oil hydraulic spool valve using different model approaches." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199607.
Jaegle, Félix. "LARGE EDDY SIMULATION OF EVAPORATING SPRAYS IN COMPLEX GEOMETRIES USING EULERIAN AND LAGRANGIAN METHODS." Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2009. http://tel.archives-ouvertes.fr/tel-00452501.
Marta, Garcia. "Développement et validation du formalisme Euler-Lagrange dans un solveur parallèle et non-structuré pour la simulation aux grandes échelles." Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2009. http://tel.archives-ouvertes.fr/tel-00414067.
Baillard, Clément. "Simulation numérique du refroidissement par spray en régime de Leidenfrost." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0327/document.
In the metallurgy industry, the cooling is a fundamental stage which allows to bring certain qualities to materials (mechanical resistance, flexibility). The impact of a spray is one known process but it is not well understood, limiting its today's scopes. This thesis aims at developing a simulation procedure, in order to obtain a useful numerical tool for the study and the future optimization of the spray cooling. Literature highlights the multitude of the mechanisms of spray cooling, but also the few existing information linking these mechanisms and the characteristics of the spray (diameter, speed and space distribution of droplets). In order to simulate the spray cooling, one proposes to split this process in two stages, the spray flow and the calculation of the cooling. Based on the literature, a correlation on the density of flow of heat removed from the plat is used to link the two stages. A full spray characterization is realized thanks to several experimental tools: Phase Doppler Analyser, speed-camera, measure of surface liquid flow density. Key elements required to characterize and also to initialize the spray in the simulation, are highlighted as well. The method of initialization, the numerical configuration (Eulerian-Lagrangian simulation, RANS k-ω turbulence model), as well as the domain of calculation are validated with the simulation of a free-fall spray. The method is then used to calculate characteristics of the spray in the presence of a surface. Finally, the cooling of plate is simulated, bringing results on the heat flow density removed from the plate in accordance with characteristics of the spray. Main results concern the highlighting of major points of simulation communally used but leading to error in the cooling simulation
Gaston, Laurence. "Simulation numérique par éléments finis bidimensionnels du remplissage de moules de fonderie et étude experimentale sur maquette hydraulique." ENSMP, 1997. http://www.theses.fr/1997ENMP0741.
This work deals with the numerical simulation of unsteady free surface flows of incompressible viscous fluids with the finite element method. In order to overcome the limitations due to both purely Eulerian and purely Lagrangian approaches, an intermediate ALE (Arbitrary Lagrangian Eulerian) formulation is proposed : at each time increment, the mechanical equilibrium (incompressible Navier-Stokes equations) is solved on the fluid domain, after time and space discretization. At the same time, a mesh velocity is computed using a regularization technique that enables to keep the mesh as near as possible to the optimum and respects the material flux. The thermal equilibrium is solved in an uncoupled way, and turbulent effects, if present, are taken into account via a standard k-Є model. The resulting filling software has been validated on various classical test cases, and succesfully compared to results of metal flows on an instrumented mould. In addition, hydraulic experiments on a transparent model have shown the ability of the present approach to describe free surface evolutions in complex geometries, such as those encoutered in casting
Euzenat, Florian. "Simulation numérique directe et analyse des transferts de chaleur dans les lits de particules fixes et mobiles." Phd thesis, Toulouse, INPT, 2017. http://oatao.univ-toulouse.fr/21358/1/EUZENAT_Florian.pdf.
Dellinger, Nicolas. "Modélisation de la formation et de l’évolution des particules de suie en approche hybride Euler-Lagrange pour la simulation de foyers aéronautiques." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS074.
Soot has become an important issue in the design of aeroengine combustors. New certifications on soot particles are to be applied in 2020 due to growing concern about pollutant emissions in the transportation industry. Soot particles also modify radiative heat transfers in combustion chambers affecting thermal load at walls and NOx formation. Still, efficient and accurate prediction of soot particles formation and evolution is an open field in CFD. This manuscript proposes to combine a Eulerian description of soot precursors and a Lagrangian description of particles evolution, which has the advantage to be well suited to follow the evolution of the particle size distribution. The growth of polycyclic aromatic hydrocarbons is modelled by a sectional method to obtain the soot inception rate and create the particles tracked in the gas flow. The particles are described as spheres interacting with the gas through chemical processes and between each other by coalescence, bounded to young liquid-like particles depending on their diameter. The method is implemented in the CEDRE code and completed by an algorithm for the reduction of the particles population to limit the cost of its statistical convergence. Applied to steady laminar premixed C2H4-air flames, it is confronted with some success to measurements of soot volume fraction, particle diameter and species molar fractions. The method is then applied combined with the Quasi-Steady State Approximation for gas chemistry to a swirled pressurized C2H4-air flame, similar to RQL configurations of aeroengine combustors, and confronted with some success to velocity, temperature, composition and soot volume fraction measurements
Bernard, Manuel. "Approche multi-échelle pour les écoulements fluide-particules." Phd thesis, Toulouse, INPT, 2014. http://oatao.univ-toulouse.fr/12239/1/Bernard.pdf.
Thuillet, Swann. "Simulation multi-échelle de l’atomisation d’un jet liquide sous l’effet d’un écoulement gazeux transverse en présence d’une perturbation acoustique." Thesis, Toulouse, ISAE, 2018. http://www.theses.fr/2018ESAE0033/document.
The reduction of polluting emissions is currently a major issue in the aeronautics industry.Among the solutions developed by the engine manufacturers, lean combustion appears as an effectivetechnology to reduce the impact of combustion on the environment. However, this type oftechnology enhances the onset of combustion instabilities, resulting from a thermo-acoustic coupling.Experimental studies previously conducted at ONERA have highlighted the importanceof atomization in a multipoint injector to the combustion instabilities. The aim of this thesis isto implement the multi-scale methodology to reproduce the coupling phenomena between theatomization of the liquid jet in the presence of a crossflow (which is a simplified configuration ofan injection point of a multipoint injector) and an imposed acoustic perturbation, representativeof the effect of combustion instabilities. This type of approach can ultimately be used for the unsteadysimulation of a combustion system, and will determine the characteristic convection timesof the liquid fuel that can affect the phenomena of evaporation and combustion, and therefore theappearance of combustion instabilities. In order to validate this approach, the results obtainedfrom the simulations are systematically compared with the experimental observations obtainedwithin the framework of the SIGMA project. First, a simulation of the liquid jet in gaseous crossflowis performed. This simulation enabled us to validate the multi-scale approach : to this end,the large scales of the jet, as well as the atomization mechanisms reproduced by the simulations,are analyzed. Then, the influence of an acoustic perturbation on the atomization of the liquidjet is studied. The unsteady behavior of the jet and the spray resulting from the atomization arecompared with the experimental results using time averages and phase averages
Caillau, Philippe. "Modélisation et simulation de la combustion turbulente par une approche probabiliste eulérienne lagrangienne." Rouen, 1994. http://www.theses.fr/1994ROUES080.
Pit, Fabienne. "Modélisation du mélange pour la simulation d'écoulements réactifs turbulents : essais de modèles eulériens lagrangiens." Rouen, 1993. http://www.theses.fr/1993ROUE5020.
Olmos, Eric. "Étude expérimentale et numérique des écoulements gaz-liquide en colonne à bulles." Vandoeuvre-les-Nancy, INPL, 2002. http://www.theses.fr/2002INPL045N.
Chagras, Valérie. "Simulation eulérienne-lagrangienne d'écoulements gaz-solide non isothermes : interactions particules-turbulence, application aux écoulements en conduite." Phd thesis, Université Henri Poincaré - Nancy I, 2004. http://tel.archives-ouvertes.fr/tel-00007697.
Guerdoux, Simon. "Simulation numérique du soudage par frottement malaxage." Phd thesis, École Nationale Supérieure des Mines de Paris, 2007. http://tel.archives-ouvertes.fr/tel-00271234.
Barras, Guillaume. "Interaction fluide-structure : application aux explosions sous-marines en champ proche." Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10003/document.
In military shipbuilding, ships are designed to withstand conventional threats such as mines or torpedoes. These designs are based on calculations of structural response to underwater explosions in far field, what is relatively well controlled today. The thematic of underwater explosions has indeed benefited from extensive research since the Second World War. This has resulted in robust numerical methods to simulate the main phenomena that characterize such events. These methods used in engineering are based on assumptions that limit their scope. These restrictions are discriminatory when we attempt to simulate underwater explosions in near field which are mainly nonlinear phenomena. In this context, the Multi-Material Arbitrary Lagrangian-Eulerian method with Euler-Lagrange coupling is chosen to simulate these problems. To make the method more easily applicable in engineering, its adaptation is based on two points. (1) Firstly the method is developed for two-dimensional cases in order to solve 2D axisymmetric problems with higher speed and accuracy compared to 3D simulations. (2) Then the projection of results from two-dimensional analysis on 2D or 3D grids is implemented. The projection from one grid to the other allows solving the whole problem through successive phases for physics on very different time scales and space scales, what necessitates adapted meshes. The developments are implemented in LS-DYNA code for the revised version 5.1.1 and validated for the different phases of the problem from theoretical and experimental results
Cesco, Nathalie. "Étude et modélisation de l'écoulement diphasique à l'intérieur des propulseurs à poudre." Toulouse, ENSAE, 1997. http://www.theses.fr/1997ESAE0019.
Bendjeddou, Zaky. "Méthodologie pour la simulation numérique des vibrations induites par écoulements dans les faisceaux de tubes." Lille 1, 2005. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2005/50376-2005-81.pdf.
Aquelet, Nicolas. "Modélisation de l'impact hydrodynamique par un couplage fluide-structure." Lille 1, 2004. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2004/50376-2004-Aquelet.pdf.
Abbas, Fatima. "Modélisation et simulation numérique de la déformation et la rupture de la plaque d'athérosclérose dans les artères." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMLH05/document.
This thesis is devoted to the mathematical modeling of the blood flow in stenosed arteries due to atherosclerosis. Atherosclerosis is a complex vascular disease characterized by the build up of a plaque leading to the narrowing of the artery. It is responsible for heart attacks and strokes. Regardless of the many risk factors that have been identified- cholesterol and lipids, pressure, unhealthy diet and obesity- only mechanical and hemodynamic factors can give a precise cause of this disease. In the first part of the thesis, we introduce the three dimensional mathematical model describing the blood-wall setting. The model consists of coupling the dynamics of the blood flow given by the Navier-Stokes equations formulated in the Arbitrary Lagrangian Eulerian (ALE) framework with the elastodynamic equations describing the elasticity of the arterial wall considered as a hyperelastic material modeled by the non-linear Saint Venant-Kirchhoff model as a fluid-structure interaction (FSI) system. Theoretically, we prove local in time existence and uniqueness of solution for this system when the fluid is assumed to be an incompressible Newtonian homogeneous fluid and the structure is described by the quasi-incompressible non-linear Saint Venant-Kirchhoff model. Results are established relying on the key tool; the fixed point theorem. The second part is devoted for the numerical analysis of the FSI model. The blood is considered to be a non-Newtonian fluid whose behavior and rheological properties are described by Carreau model, while the arterial wall is a homogeneous incompressible material described by the quasi-static elastodynamic equations. Simulations are performed in the two dimensional space R^2 using the finite element method (FEM) software FreeFem++. We focus on investigating the pattern of the viscosity, the speed and the maximum shear stress. Further, we aim to locate the recirculation zones which are formed as a consequence of the existence of the stenosis. Based on these results we proceed to detect the solidification zone where the blood transits from liquid state to a jelly-like material. Next, we specify the solidified blood to be a linear elastic material that obeys Hooke's law and which is subjected to an external surface force representing the stress exerted by the blood on the solidification zone. Numerical results concerning the solidified blood are obtained by solving the linear elasticity equations using FreeFem++. Mainly, we analyze the deformation of this zone as well as the wall shear stress. These analyzed results will allow us to give our hypothesis to derive a rupture model
Frank, Thomas. "Parallele Algorithmen für die numerische Simulation dreidimensionaler, disperser Mehrphasenströmungen und deren Anwendung in der Verfahrenstechnik." Universitätsbibliothek Chemnitz, 2002. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200201013.
Viele der in Natur und Technik ablaufenden Strömungsvorgänge sind durch die Koexistenz zweier oder mehrerer Phasen gekennzeichnet. Diese sogenannten Zwei- oder Mehrphasensysteme zeichnen sich durch ein hohes Maß an Komplexität aus und erfordern oft einen sehr hohen rechentechnischen Aufwand zu deren numerischer Simulation. Die vorliegende Arbeit faßt langjährige Forschungs- und Entwicklungsarbeiten des Autors und seiner Forschungsgruppe "Numerische Methoden für Mehrphasenströmungen" an der TU Chemnitz zusammen, die sich mit der Entwicklung und Anwendung numerischer Berechnungsverfahren für disperse Fluid-Partikel-Strömungen auf dem Gebiet der Strömungs- und Verfahrenstechnik befassen. Ein wesentlicher Teil der Arbeit befaßt sich mit der Modellierung unterschiedlicher physikalischer Phänomene in Fluid-Partikel-Strömungen unter dem Paradigma der Lagrange'schen Betrachtungsweise der Partikelbewegung. Das Euler-Lagrange-Verfahren hat sich als besonders geeignetes Berechnungsverfahren für die numerische Simulation disperser Mehrphasenströmungen erwiesen, stellt jedoch in seiner Anwendung auch höchste Anforderungen an die Ressourcen der verwendeten (parallelen) Rechnerarchitekturen. Die näher ausgeführten mathematisch-physikalischen Modelle liefern eine Beschreibung der auf eine kugelförmige Einzelpartikel im Strömungsfeld wirkenden Kräfte und Momente, der Partikel-Wand-Wechselwirkung und der Partikelerosion. Weitere Teilmodelle dienen der Berücksichtigung von Partikel-Partikel-Stoßvorgängen und der Wechselwirkung zwischen Fluidturbulenz und Partikelbewegung. Der Schwerpunkt dieser Arbeit liegt im Weiteren in der Entwicklung, Untersuchung und vergleichenden Bewertung von Parallelisierungsverfahren für das Euler-Lagrange-Verfahren zur Berechnung von dispersen Mehrphasenströmungen. Zuvor von anderen Autoren entwickelte Parallelisierungsmethoden für das Lagrange'sche Berechnungsverfahren basieren im Wesentlichen auf Shared-Memory-Ansätzen, Quasi-Seriellen Verfahren oder statischer Gebietszerlegung (SDD) und sind somit in ihrer Einsetzbarkeit und Skalierbarkeit auf Rechnerarchitekturen mit relativ geringer Parallelität und auf weitgehend homogene Mehrphasenströmungen mit geringer Komplexität der Phasenwechselwirkungen beschränkt. In dieser Arbeit wird eine vom Autor entwickelte, neuartige Parallelisierungsmethode vorgestellt, die eine dynamische Lastverteilung für das Lagrange-Verfahren ermöglicht (DDD - Dynamic Domain Decomposition) und mit deren Hilfe eine deutliche Reduzierung der Gesamtausführungszeiten einer Mehrphasenströmungsberechnung mit dem Euler-Lagrange-Verfahren möglich ist. Im Ergebnis steht mit dem vom Autor und seiner Forschungsgruppe entwickelten vollständig parallelisierten Euler-Lagrange-Verfahren MISTRAL/PartFlow-3D ein numerisches Berechnungsverfahren zur Verfügung, mit dem disperse Mehrphasenströmungen mit höheren Konzentrationen der dispersen Phase und daraus resultierenden starken Phasenwechselwirkungen (Vier-Wege-Kopplung) effektiv untersucht werden können
Ould, Salihi Mohamed Lemine. "Couplage de méthodes numériques en simulation directe d'écoulements incompressibles." Phd thesis, Université Joseph Fourier (Grenoble), 1998. http://tel.archives-ouvertes.fr/tel-00004901.
Pachler, Klaus, Thomas Frank, and Klaus Bernert. "Simulation of Unsteady Gas-Particle Flows including Two-way and Four-way Coupling on a MIMD Computer Architectur." Universitätsbibliothek Chemnitz, 2002. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200200352.
Morvan, Antoine. "Impact sur le pont mouillé d’un navire SWATH pour la maintenance des éoliennes offshore." Thesis, Brest, École nationale supérieure de techniques avancées Bretagne, 2019. http://www.theses.fr/2019ENTA0003.
The aim of this PhD thesis is to develop simplified models about hydrodynamic impact (slamming) on the wet deck of a SWATH vessel for the maintenance of offshore wind turbines. The knowledge of the hydrodynamic loadings that the wet deck is subjected is an essential step in the design of the vessel’s bow. To realise this study we chose a parabolic twodimensional geometry which symbolises the wet deck and a regular Airy wave for the moving free surface. The models developed are based on the Wagner theory which provides relevant results for a low computational time. Two types of impact models have been developed. So-called asymptotic models, because they use a Taylor expansion of the wave profil and non-asymptotic models because they retain the whole shape of the wave. The pressure distributions on the parabolic shape are mainly calculated by the Modified Logvinovich Model (MLM). The results in terms of wetted corrections, pressure fields and hydrodynamic loadings are compared between the two types of models as a function of the wave radius of curvature We also determine the hydrodynamic impact arrangement which produces the highest hydrodynamic loadings by using reference configurations. For non-asymptotic models, the contribution of wave amplitude and phase velocity within hydrodynamic loadings is analysed in details. For non-asymptotic models, we made the study of the spatial and time variations of pressure fields computed with the linearized Bernoulli equation. We also compared the results of composite theory (COMP) to MLM theory and their consequences on hydrodynamic loadings. Finally, in order to get a basis of comparison for these regular Airy wave impact models, we implemented a numerical model using ABAQUS/CAE software. This model is based on a Coupled Eulerian-Lagrangian (CEL) coupling and show good matching with the results of non-asymptotic models in terms of relative errors. In a design office, all those results can be used to help design of the wet deck of a SWATH vessel
Bhatnagar, Akshay. "Direct Numerical Simulations of Fluid Turbulence : (A) Statistical Properties of Tracer And Inertial Particles (B) Cauchy-Lagrange Studies of The Three Dimensional Euler Equation." Thesis, 2016. http://etd.iisc.ac.in/handle/2005/2747.
Bhatnagar, Akshay. "Direct Numerical Simulations of Fluid Turbulence : (A) Statistical Properties of Tracer And Inertial Particles (B) Cauchy-Lagrange Studies of The Three Dimensional Euler Equation." Thesis, 2016. http://hdl.handle.net/2005/2747.
Matysiak, Andreas [Verfasser]. "Euler-Lagrange-Verfahren zur Simulation tropfenbeladener Strömung in einem Verdichtergitter / vorgelegt von Andreas Matysiak." 2007. http://d-nb.info/984896678/34.
Senoner, Jean-Mathieu. "Large-Eddy Simulation of the two-phase flow in an aeronautical combustor using an Euler-Lagrange approach." Phd thesis, 2010. http://oatao.univ-toulouse.fr/7215/1/senoner1.pdf.
Emans, Maximilian [Verfasser]. "Numerische Simulation des unterkühlten Blasensiedens in turbulenter Strömung : ein Euler-Lagrange-Verfahren auf orthogonalen Gittern / Maximilian Emans." 2003. http://d-nb.info/970212860/34.
Dapelo, Davide, and John Bridgeman. "Euler-Lagrange Computational Fluid Dynamics simulation of a full-scale unconfined anaerobic digester for wastewater sludge treatment." 2017. http://hdl.handle.net/10454/17925.
For the first time, an Euler-Lagrange model for Computational Fluid Dynamics (CFD) is used to model a full-scale gas-mixed anaerobic digester. The design and operation parameters of a digester from a wastewater treatment works are modelled, and mixing is assessed through a novel, multi-facetted approach consisting of the simultaneous analysis of (i) velocity, shear rate and viscosity flow patterns, (ii) domain characterization following the average shear rate value, and (iii) concentration of a non-diffusive scalar tracer. The influence of sludge’s non-Newtonian behaviour on flow patterns and its consequential impact on mixing quality were discussed for the first time. Recommendations to enhance mixing effectiveness are given: (i) a lower gas mixing input power can be used in the digester modelled within this work without a significant change in mixing quality, and (ii) biogas injection should be periodically switched between different nozzle series placed at different distances from the centre.
The first author is funded via a University of Birmingham Postgraduate Teaching Assistantship award.