Дисертації з теми "Finite Volume Solver"
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Car, David. "A generalized unstructured finite volume solver with application to turbomachinery." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/49953.
Повний текст джерелаJalali, Alireza. "An adaptive higher-order unstructured finite volume solver for turbulent compressible flows." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/60365.
Повний текст джерелаApplied Science, Faculty of
Mechanical Engineering, Department of
Graduate
Hoshyari, Shayan. "A higher-order unstructured finite volume solver for three-dimensional compressible flows." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62846.
Повний текст джерелаApplied Science, Faculty of
Mechanical Engineering, Department of
Graduate
Greiner, Ken. "A finite volume solver for viscous turbulent flows on mixed element unstructured meshes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0014/MQ40896.pdf.
Повний текст джерелаRees, Ian. "Development of an edge-based finite volume solver for porous media flow applications." Thesis, Swansea University, 2004. https://cronfa.swan.ac.uk/Record/cronfa43012.
Повний текст джерелаBaumann, Dirk. "A 3-D numerical field solver based on the finite-volume time-domain method /." Zürich : ETH, 2006. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16650.
Повний текст джерелаVantieghem, Stijn. "Numerical simulations of quasi-static magnetohydrodynamics using an unstructured finite volume solver: development and applications." Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209929.
Повний текст джерелаLa première partie de cette thèse (chapitres 2 et 3) est dédiée à la présentation de la machinerie numérique qui a été utilisée et implémentée afin de résoudre les équations de la MHD quasi-statistique (incompressible). Plus précisément, nous avons contribué au développement d’un solveur volumes finis non-structuré parallèle. La discussion sur ces méthodes est accompagnée d’une analyse numérique qui est aussi valable pour des mailles non-structurées. Dans le chapitre 3, nous vérifions notre implémentation par la simulation d’un certain nombre de cas tests avec un accent sur des écoulements dans un champ magnétique intense.
Dans la deuxième partie de cette thèse (chapitres 4-6), nous avons utilsé ce solveur pour étudier des écoulements MHD de proche paroi .La première géometrie considérée (chapitre 4) est celle d’une conduite circulaire infini d’axe à haut nombre de Hartmann. Nous avons investitgué la sensitivité des résultats numériques au schéma de discrétisation et à la topologie de la maille. Nos résultats permettent de caractériser in extenso l’écoulement MHD dans une conduite avec des bords bien conducteurs par moyen des lois d’échelle.
Le sujet du cinquième chapitre est l’écoulement dans une conduite toroïdale à section carée. Une étude du régime laminaire confirme une analyse asymptotique pour ce qui concerne les couches de cisaillement. Nous avons aussi effectué des simulations des écoulements turbulents afin d’évaluer l’effet d’un champ magnétique externe sur l’état des couches limites limites.
Finalement, dans le chapitre 6, nous investiguons l’écoulement MHD et dans un U-bend et dans un coude arrière. Nous expliquons comment générer une maille qui permet de toutes les couches de cisaillement à un coût computationelle acceptable. Nous comparons nos résultats aux solutions asymptotiques.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Johnson, Perry. "Thermoacoustic Riemann Solver Finite Volume Method with Application to Turbulent Premixed Gas Turbine Combustion Instability." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5952.
Повний текст джерелаM.S.M.E.
Masters
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering; Thermo-Fluids
Rycroft, Noel Christopher. "An adaptive, three-dimensional, finite volume, euler solver for distributed architectures using arbitrary polyhedral cells." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266866.
Повний текст джерелаMusta, Mustafa Nail. "Implementation Of Turbulence Models Into A Navier-stokes Solver." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605357/index.pdf.
Повний текст джерелаBhogireddy, Venkata Sai Pavan Kumar. "Phase Field modeling of sigma phase transformation in duplex stainless steels : Using FiPy-Finite Volume PDE solver." Thesis, KTH, Materialvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-161712.
Повний текст джерелаOzdemir, Enver Doruk. "Implementation Of Rotation Into A 2-d Euler Solver." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606525/index.pdf.
Повний текст джерелаsecondly, implementation of first order Roe&rsquo
s flux splitting scheme and lastly, the implementation of rotation with the help of Arbitrary Lagrangian Eulerian (ALE) method. For the verification of steady and unsteady results of the code, the experimental and computational results from literature are utilized. For steady conditions, subsonic and transonic cases are investigated with different angle of attacks. For the verification of unsteady results of the code, oscillating airfoil case is used. The flow is assumed as inviscid, unsteady, adiabatic and two dimensional. The gravity is neglected and the air is taken as ideal gas. The developed code is run on computers housed in METU Mechanical Engineering Department Computational Fluid Dynamics High Performance Computing (CFD-HPC) Laboratory.
Edelvik, Fredrik. "Hybrid Solvers for the Maxwell Equations in Time-Domain." Doctoral thesis, Uppsala universitet, Avdelningen för teknisk databehandling, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-2156.
Повний текст джерелаAGARWAL, SIDDHANT. "Implementation of k-Exact Finite Volume Reconstruction in DLR’s Next-Generation CFD Solver: Flucs and its Comparison to Other Methods." Thesis, KTH, Mekanik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-220315.
Повний текст джерелаDetta examensarbete vidareutvecklade ordningen av rekonstruktion av tillståndet för konvektiva flöden som används av FV-algoritmen i DLR’s nästa generations CFD-lösare: Flucs, från konstant och linjär till kvadratisk och kubisk. Två metoder för beräkning av derivatorna genomfördes i Flucs och några testfall försökades. För att möjliggöra integrationen av momenten inom varje cell och integrationen av flöden på en högre ordning, matades det nät som används av DG till FV-algoritmen. Otillräcklig geometrisk behandling av gränscellerna och dummycellerna antas vara skadlig för ordning av felreduceringen i NACA0012-fallet och det Smmoth Bump-fallet. I det Smooth Bump-Fallet fick FV-algoritmerna inte visa högre än andra ordning av felreducering på grund av denna anledning. Ordningen av schemana bort från gränserna verifierades med Ehrenfried Vortex-testfallet. För åtminstone strukturerade nät och ostrukturerade nät med fyrkantiga celler nådde algorithmer med order k, k + 1 ordernoggrannhet på tillräckliga bra nät. Det ursprungliga målet för denna avhandling uppnåddes delvis och ytterligare arbete i koden förväntas.
Akturk, Ali. "Two-dimensional Finite Volume Weighted Essentially Non-oscillatory Euler Schemes With Different Flux Algorithms." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606387/index.pdf.
Повний текст джерелаLhebrard, Xavier. "Analyse de quelques schémas numériques pour des problèmes de shallow water." Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC1019/document.
Повний текст джерелаWe build and analyze mathematically numerical approximations by finite volume methods of weak solutions to hyperbolic systems for geophysical flows. In a first part we approximate the solutions of the shallow water magneto hydrodynamics system with flat bottom. We develop a Godunov scheme using an approximate Riemann solver defined via a relaxation method. Explicit formulas are established for the relaxation speeds, that lead to a scheme satisfying good properties of consistency and stability. It preserves mass, positivity of the fluid height, satisfies a discrete entropy inequality, resolves contact discontinuities, and involves propagation speeds controlled by the initial data. Several numerical tests are performed, endorsing the theoretical results. In a second part we approximate the solutions of the shallow water magneto hydrodynamics system with non-flat bottom. We develop a well-balanced scheme for several steady states at rest. We use the hydrostatic reconstruction method, with reconstructed states for the fluid height and the magnetic field. We get some new corrective terms for the numerical fluxes with respect to the classical framework, and we prove that the obtained scheme preserves the positivity of height, satisfies a semi-discrete entropy inequality, and is consistent. Several numerical tests are presented, endorsing the theoretical results. In a third part we prove the convergence of a kinetic scheme with hydrostatic reconstruction for the Saint-Venant system with topography. Some new estimates on the gradient of approximate solutions are established, by the analysis of energy dissipation. The convergence is obtained by the compensated compactness method, under some hypotheses concerning the initial data and the regularity of the topography
Haider, Jibran. "An upwind cell centred finite volume method for large strain explicit solid dynamics in OpenFOAM." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/565419.
Повний текст джерелаEn aplicaciones prácticas de ingeniería que implican geometrías extremadamente complejas, el mallado requiere típicamente una gran parte del tiempo total de diseño y análisis. En la comunidad de mecánica computacional, la capacidad de realizar cálculos sobre mallas tetraédricas está siendo cada vez más importante. Por estas razones, la generación automatizada de mallas tetraédricas por medio de técnicas de Delaunay y frente avanzado han recibido cada vez más atención en ciertas aplicaciones, a saber: simulaciones de impacto, modelado cardiovascular, modelado de explosión y fractura. Por desgracia, los códigos en la industria moderna para mecánica de sólidos se basan normalmente en el uso de formulaciones tradicionales de Elementos Finitos formulados en desplazamientos que poseen varias desventajas: (1) menor orden de convergencia para tensiones y deformaciones; (2) ruido de alta frecuencia cerca de las ondas de choque; y (3) inestabilidades numéricas asociadas con el bloqueo a cortante, el bloqueo volumétrico y oscilaciones de presión. Con el fin de abordar estas deficiencias, se introduce un nuevo conjunto de ecuaciones para mecánica del sólido formulada como un sistema de leyes de conservación de primer orden basada en una formulación mixta. Fundamentalmente, el nuevo sistema de leyes de conservación tiene una estructura similar a la de las famosas ecuaciones de Euler en el contexto de la Dinámica de Fluidos Computacional (CFD). Esto nos permite aprovechar algunas de las tecnologías CFD disponibles y adaptar el método en el contexto de la Mecánica de Sólidos. Esta tesis se basa en el trabajo realizado en Lee et al. 2013 mediante el desarrollo de la estructura de volúmenes finitos centrados en celdas upwind para el análisis numérico de dinámica del sólido explícita en grandes deformaciones y su implementación específicamente diseñada dentro del software de código abierto OpenFOAM, ampliamente utilizado ámbito académico e industrial. Además, la naturaleza orientada a objetos de su implementación proporciona una plataforma muy eficiente para su desarrollo posterior. En este marco computacional, las incógnitas básicas de este sistema son el momento lineal y el tensor gradiente de deformación. Asimismo, la formulación se extiende adicionalmente para un conjunto adicional de medidas de deformación que comprenden el cofactor del tensor gradiente de deformación y el jacobiano de deformación, con el fin de simular modelos constitutivos policonvexos que aseguran la estabilidad del material. El dominio se discretiza espacialmente usando un marco centrado en células de tipo Godunov estándar, donde se consigue la precisión de segundo orden empleando un procedimiento de reconstrucción lineal junto con un limitador de pendiente. Esto conduce a discontinuidades en las variables en la interfase de la célula que motivan el uso de un solucionador de Riemann mediante la introducción de un sesgo contra el viento en la evaluación de flujos de contacto numéricos. El presente solucionador acústico de Riemann es posteriormente desarrollado aplicando disipación pre-condicionada para mejorar su rendimiento en el cercano pero incompresibilidad régimen y extender su gama a aplicaciones de contacto. Además, se proponen dos marcos evolutivos en este estudio para satisfacer las involuciones subyacentes (o condiciones de compatibilidad) del sistema. Además, la discretización espacial se representa alternativamente a través de un marco de volumen finito centrado en células nodales para fines de comparación. Desde el punto de vista de la discretización temporal, se emplea un integrador temporal de Runge-Kutta de dos etapas con Disminución de Variación Total para asegurar segundo orden de precision. Finalmente, se simulan ejemplos numéricos de referencia para demostrar varios aspectos de la formulación que incluyen convergencia de malla, conservación de momento y la naturaleza libre de bloqueo de la formulación en dominios computacionales complejos.
Akin, Ayhan. "Development Of A Laminar Navier-stokes Solver For Incompressible Flows Using Structured Grids." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607206/index.pdf.
Повний текст джерелаAybay, Orhan. "Implementation Of The Spalart-allmaras Turbulence Model To A Two-dimensional Unstructured Navier-stokes Solver." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12605725/index.pdf.
Повний текст джерелаMustafa, Akdemir. "Development Of An Axisymmetric, Turbulent And Unstructured Navier-stokes Solver." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611904/index.pdf.
Повний текст джерелаContact (HLLC) upwind flux differencing scheme for spatial and uses Runge-Kutta explicit multi-stage time stepping scheme for temporal discretization on unstructured meshe is developed. Developed solver can solve the compressible axisymmetric flow. The spatial accuracy of the solver can be first or second order accurate. Second order accuracy is achieved by piecewise linear reconstruction. Gradients of flow variables required for piecewise linear reconstruction are calculated by Green-Gauss theorem. Baldwin-Lomax turbulent model is used to compute the turbulent viscosity. Approximate Riemann solver of HLL and HLLC implemented in solver are validated by solving a cylindrical explosion case. Also the solver&rsquo
s capability of solving unstructured, multi-zone domain is investigated by this problem. First and second order results of solver are compared by solving the flow over a circular bump. Axisymmetric flow in solid propellant rocket motor is solved in order to validate the axisymmetric feature of solver. Laminar flow over flat plate is solved for viscous terms validation. Turbulent model is studied in the flow over flat plate and flow with mass injection test cases.
Mullenix, Nathan Joel. "Fully Coupled Model for High-Temperature Ablation and a Reative-Riemann Solver for its Solution." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1271035105.
Повний текст джерелаLockwood, Brian Alan. "A two dimensional fluid dynamics solver for use in multiphysics simulations of gas cooled reactors." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/24820.
Повний текст джерелаCommittee Co-Chair: de Oliveira, Cassiano; Committee Co-Chair: Ghiaasiaan, S. Mostafa; Committee Member: Martineau, Richard C.; Committee Member: van Rooijen, W.F.G
Coskun, Korhan. "Three Dimensional Laminar Compressible Navier Stokes Solver For Internal Rocket Flow Applications." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12609086/index.pdf.
Повний текст джерелаs upwind flux differencing scheme for spatial and Runge-Kutta explicit multi-stage time stepping scheme and implicit Lower-Upper Symmetric Gauss Seidel (LU-SGS) iteration scheme for temporal discretization on unstructured and hybrid meshes is developed for steady rocket internal viscous flow applications. The spatial accuracy of the solver can be selected as first or second order. Second order accuracy is achieved by piecewise linear reconstruction. Gradients of flow variables required for piecewise linear reconstruction are calculated with both Green-Gauss and Least-Squares approaches. The solver developed is first verified against the three-dimensional viscous laminar flow over flat plate. Then the implicit time stepping algorithms are compared against two rocket motor internal flow problems. Although the solver is intended for internal flows, a test case involving flow over an airfoil is also given. As the last test case, supersonic vortex flow between concentric circular arcs is selected.
Andriulli, Raoul. "Development of an OpenFOAM solver for particle migration in the casting process of solid rocket motors." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/24352/.
Повний текст джерелаGenc, Balkan Ziya. "Implementation And Comparison Of Turbulence Models On A Flat Plate Problem Using A Navier-stokes Solver." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1096668/index.pdf.
Повний текст джерелаs k-epsilon and Wilcox&rsquo
s k-omega turbulence models. To evaluate the performances of these turbulence models and to compare them with each other, the solver has been tested for a case of subsonic, laminar - transition fixed - turbulent flow over a flat plate. The results are verified by analytical solutions and empirical correlations.
Cao, Zhixin. "Non-oscillatory forward-in-time method for incompressible flows." Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/33265.
Повний текст джерелаGhavamian, Ataollah. "Un cadre de calcul pour un système de premier ordre de lois de conservation en thermoélasticité." Thesis, Ecole centrale de Nantes, 2020. http://www.theses.fr/2020ECDN0004.
Повний текст джерелаIt is evidently not trivial to analytically solve practical engineering problems due to their inherent nonlinearities. Moreover, experimental testing can be extremely costly and time-consuming. In the past few decades, therefore, numerical techniques have been progressively developed and utilised in order to investigate complex engineering applications through computer simulations. In the context of fast thermo-elastodynamics, modern commercial packages are typically developed on the basis of second order displacement-based finite element formulations and, unfortunately, that introduces a series of numerical shortcomings (e.g. detrimental locking, hour-glass modes, spurious pressure oscillations). To rectify these drawbacks, a mixed-based set of first order hyperbolic conservation laws for thermo- elastodynamics is presented in terms of the linear momentum per unit undeformed volume, the deformation gradient, its co-factor, its Jacobian and the balance of total Energy. Interestingly, the conservation formulation framework allows exploiting available CFD techniques in the context of solid dynamics. From a computational standpoint, two distinct spatial discretisations are employed, namely, Vertex-Centred Finite Volume Method (VCFVM) and Smooth Particle Hydrodynamics (SPH). A linear reconstruction procedure together with a slope limiter is employed in order to ensure second order accuracy in space whilst avoiding numerical oscillations in the vicinity of sharp gradients. The semi-discrete system of equations is then temporally discretised using a second-order Total Variation Diminishing (TVD) Runge-Kutta time integrator. Finally, a wide spectrum of challenging examples is presented in order to assess both the performance and applicability of the proposed schemes. The new formulation is proven to be very efficient in nearly incompressible thermoelasticity in comparison with classical finite element displacement-based approaches
Edelvik, Fredrik. "Finite volume solvers for the Maxwell equations in time domain." Licentiate thesis, Uppsala universitet, Avdelningen för teknisk databehandling, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-86389.
Повний текст джерелаMontagnier, Julien. "Etude de schémas numériques d'ordre élevé pour la simulation de dispersion de polluants dans des géométries complexes." Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00502476.
Повний текст джерелаMARTINS, ROBERTO SANTOS. "FINITE ELEMENT METHOD BASED ON CONTROL VOLUME TO SOLVE FLOW FIELD." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1996. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=18995@1.
Повний текст джерелаCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
Neste trabalho estudou-se um método numérico para simulação de processos Envolvendo transporte convectivo de calor e massa. A metodologia é baseada no Método de elementos finitos, utilizando-se o conceito de volumes de controle, e tem Como objetivo lidar com geometrias irregulares e malhas não uniformes. A formulação é baseada em variáveis primitivas, e atribui-se grande importância à interpretação da formulação em termos de grandezas com significado físico tais como fluxos, forças e fontes. Em problemas que não envolvem o cálculo do escoamento,o domínio de cálculo é discretizado utilizando-se elementos triangulares de três nós. Nos demais problemas, o domínio é primeiramente discretizado utilizando-se macroelementos triangulares de seis nós, então cada macroelemento é dividido em quatro subelementos triangulares de três nós. Não há restrições quanto á forma ou tamanho destes elementos. Após esta triangularização do domínio de cálculo, associa-se a cada nó um volume de controle poligonal. A natureza do problema a ser resolvido determina as formas das funções de interpolação para as variáveis dependentes. Em problemas de condução, todas as variáveis dependentes são interpoladas linearmente em cada elemento triangular de três nós. Entretanto, em problemas envolvendo escoamento, utiliza-se funções especiais de interpolação para todas as variáveis dependentes, exceto a pressão. Estas funções de interpolação são exponenciais na direção de um vetor velocidade média no elemento e lineares na direção perpendicular ao mesmo, elas dependem do número de Peclet para o elemento, reduzindo-se a completamente linear quando este se aproxima de zero. Na formulação do método, os princípios de conservação de interesse são impostos aos volumes de controle associados aos nós. Os sistemas resultantes de equações integrais de conservação são então aproximados por equações algébricas, utilizando-se as funções de interpolação discutidas anteriormente. Estas equações algébricas,que são em geral não lineares e acopladas, são resolvidas através de um processo iterativo similiar ao método das aproximações sucessivas. Em cada ciclo deste procedimento, a pressão, os componentes da velocidade, a correção da pressão e todas as demais variáveis dependentes são resolvidas de uma forma seqüencial. Problemas testes foram realizados, apresentando bons resultados.
A general numerical method for the prediction of convenctive heat and mass transfer Process has been studied. The method has been designed to handle irregularshaped Domains and work with highly non-uniform grids. The formulation is based on Primitive variables. Considerable importance has been attached to the interpretation of the formulation in terms of physically meaningful qualities like fluxes, forces, and sources. In problems in discretized into three-node triangular elements. In all other problems, the domain is first discretized into six-node triangular macroelements, then each mecroelement is divided into four thrree-node triangular subelements. No restrictions are placed on either the shape or the dize of these elements.Following this domain triangulation, each node solved determines the forms of the interpolation fuctions for the dependent variables. In conduction-type problems,all interpolation functions for the interpolated linearly in each- three-node element. In problems involving fluid flow, however, special interpolation functions are used in each three node element,for all dependent variables expect pressure. These interpolation functions are exponencial in the direction of an element-averaged velocity vector and linear in a direction normal to it, they respond to an element Peclet number, reducing to a completely linear form when it approaches zero. In the formulation of the method, appropriate conservation laws are imposed on the polygonal control volumes associated with the nodes. The resulting sets of integral conservation equations are then aproximated by algenbraic equations, using the interpolation functions discussed above. These algebraic equations, which are non-linear and coupled, in general, are solved by an iterative procedure similar to the method of sucessive approximations. In each cycle of this procedure, the pressure, the velocity components, and all other Dependent variables are solved for in a sequencial manner. Test problems have been solved, and the results are very encouraging.
Oriani, Mattia. "A mixed hybrid finite volumes solver for robust primal and adjoint CFD." Thesis, Queen Mary, University of London, 2018. http://qmro.qmul.ac.uk/xmlui/handle/123456789/39760.
Повний текст джерелаVittoz, Louis. "Contributions au développement d’un solveur volumes finis sur grille cartésienne localement raffinée en vue d’application à l’hydrodynamique navale." Thesis, Ecole centrale de Nantes, 2018. http://www.theses.fr/2018ECDN0020/document.
Повний текст джерелаAn original strategy to address hydrodynamic flow was recently proposed through a high-order weakly-compressible Cartesian grid approach. The method is based on a fully-explicit temporal scheme for solving the Navier-Stokes equations. The present thesis aims to reduce the computational time required to obtain the results without deteriorating the accuracy.A first part is dedicated to the implementation of a truly incompressible formulation with an implicit solution for the pressure field through a projection scheme. The incompressible solver allows larger time step size for time integration since the speed of sound tends to infinity. In return the algorithms are no longer straight forward and a linear system has to be solved through the Pressure Poisson Equation. Comparisons carried out between both formulations show that the projection scheme can be better adapted to efficiently simulate unsteady viscous flows. Then an improvement of the immersed boundary method has been proposed. Results are not fully satisfactory for now. However, it seems easier to develop a numerical scheme for the incompressible approach rather than the weakly-compressible one.Finally, the last part addresses the setup up of complex triangulations in immersed boundary simulations. A fast and robust procedure is developed for distance computation with an octree data structure
Tesser, Federico. "Solveur parallèle pour l’équation de Poisson sur mailles superposées et hiérarchiques, dans le cadre du langage Python." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0129/document.
Повний текст джерелаAdaptive discretizations are important in compressible/incompressible flow problems since it is often necessary to resolve details on multiple levels,allowing large regions of space to be modeled using a reduced number of degrees of freedom (reducing the computational time).There are a wide variety of methods for adaptively discretizing space, but Cartesian grids have often outperformed them even at high resolutions due totheir simple and accurate numerical stencils and their superior parallel performances.Such performance and simplicity are in general obtained applying afinite-difference scheme for the resolution of the problems involved, but this discretization approach does not present, by contrast, an easy adapting path.In a finite-volume scheme, instead, we can incorporate different types of grids,more suitable for adaptive refinements, increasing the complexity on thestencils and getting a greater flexibility.The Laplace operator is an essential building block of the Navier-Stokes equations, a model that governs fluid flows, but it occurs also in differential equations that describe many other physical phenomena, such as electric and gravitational potentials, and quantum mechanics. So, it is a very importantdifferential operator, and all the studies carried out on it, prove itsrelevance.In this work will be presented 2D finite-difference and finite-volume approaches to solve the Laplacian operator, applying patches of overlapping grids where amore fined level is needed, leaving coarser meshes in the rest of the computational domain.These overlapping grids will have generic quadrilateral shapes.Specifically, the topics covered will be:1) introduction to the finite difference method, finite volume method, domainpartitioning, solution approximation;2) overview of different types of meshes to represent in a discrete way thegeometry involved in a problem, with a focuson the octree data structure, presenting PABLO and PABLitO. The first one is anexternal library used to manage each single grid’s creation, load balancing and internal communications, while the second one is the Python API ofthat library written ad hoc for the current project;3) presentation of the algorithm used to communicate data between meshes (beingall of them unaware of each other’s existence) using MPI inter-communicators and clarification of the monolithic approach applied building the finalmatrix for the system to solve, taking into account diagonal, restriction and prolongation blocks;4) presentation of some results; conclusions, references.It is important to underline that everything is done under Python as programmingframework, using Cython for the writing of PABLitO, MPI4Py for the communications between grids, PETSc4py for the assembling and resolution partsof the system of unknowns, NumPy for contiguous memory buffer objects.The choice of this programming language has been made because Python, easy to learn and understand, is today a significant contender for the numerical computing and HPC ecosystem, thanks to its clean style, its packages, its compilers and, why not, its specific architecture optimized versions
Gosavi, Shekhar Vishwanath. "An integrated finite element and finite volume code to solve thermo-hydro-mechanical problems in porous media." Diss., Manhattan, Kan. : Kansas State University, 2006. http://hdl.handle.net/2097/157.
Повний текст джерелаNguyen, Hung Chinh. "Simulation de modèles hydrodynamiques et de transfert radiatif intervenant dans la description d'écoulements astrophysiques." Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112073.
Повний текст джерелаThis topic is a multidisciplinary work between mathematics and astrophysics. The aim of this thesis is the study of radiation hydrodynamic models of which application is obviously very broad in physics and astrophysics. M1-multigroup models are explored to describe the radiative transfer without a priori assumption on the optical depth of the medium. The interest ensuing directly from this work is the development of a radiation hydrodynamic code, namely HADES 2D, for massively parallel computing. It allows simulations in realistic astrophysical configurations in terms of Mach number, density and temperature contrasts between different environments. We focused on two interesting applications: the jets from young stars and the radiative shocks of which first simulations will be presented
MacHardy, Laura C. "Numerical modelling of phase-averaged nearshore hydrodynamics using finite volumes and a new Roe-type Riemann solver." Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423289.
Повний текст джерелаChauveheid, Daniel. "Ecoulements multi-matériaux et multi-physiques : solveur volumes finis eulérien co-localisé avec capture d’interfaces, analyse et simulations." Thesis, Cachan, Ecole normale supérieure, 2012. http://www.theses.fr/2012DENS0032/document.
Повний текст джерелаThis work is devoted to the extension of a eulerian cell-centered finite volume scheme with interfaces capturing for the simulation of multimaterial fluid flows. Our purpose is to develop a simulation tool which could be able to handle multi-physics problems in the following sense. We address the case of radiating flows, modeled by a two temperature system of equations where the hydrodynamics are coupled to radiation transport. We address a numerical scheme for taking surface tension forces into account. An implicit scheme is proposed to handle low Mach number fluid flows by means of a renormalization of the numerical diffusion. Eventually, the scheme is extended to three-dimensional flows and to multimaterial flows, that is with an arbitrary number of materials. At each step, numerical simulations validate our schemes
Schmidtmann, Birte [Verfasser], Manuel [Akademischer Betreuer] Torrilhon, and Antonio [Akademischer Betreuer] Marquina. "On building blocks of finite volume methods : Limiter functions and Riemann solvers / Birte Schmidtmann ; Manuel Torrilhon, Antonio Marquina." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1162629509/34.
Повний текст джерелаMagalhÃes, Madson Linhares. "Modeling and simulation of process of drying convective using differential model diffusive - convective solved by method of numerical finite volumes." Universidade Federal do CearÃ, 2016. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16573.
Повний текст джерелаO consumo de energia à um fator determinante na viabilidade de qualquer processo industrial. A desidrataÃÃo tÃrmica à responsÃvel por um alto consumo de energia tÃrmica. Em paÃses desenvolvidos, o consumo da energia da indÃstria nacional à atribuÃdo, em mÃdia, entre 9-25% a desidrataÃÃo tÃrmica. Assim, o estudo do processo de secagem se mostra bastante promissor. Em produtos biolÃgicos, a secagem tem uma importÃncia especÃfica, a conservaÃÃo do produto, pois a matÃria orgÃnica do produto e a Ãgua presente nele torna este um local propÃcio para a proliferaÃÃo de micro-organismos que irÃo deteriorar o produto, tornando-o inapropriado para consumo. Neste trabalho, realizou-se a modelagem e simulaÃÃo do processo de secagem convectiva utilizando modelo diferencial difusivo-convectivo resolvido pelo mÃtodo numÃrico dos volumes finitos para predizer o comportamento do conteÃdo de umidade mÃdio durante a secagem de cubos, definir os coeficientes de transferÃncia de massa molecular e convectivo e encontrar os perfis do conteÃdo de umidade no interior do sÃlido. Para avaliar a influÃncia das resistÃncias interna e externa, o nÃmero de Biot de Massa foi obtido. A implementaÃÃo dos modelos deste trabalho foi realizada na ferramenta livre Python utilizando seus mÃdulos cientÃficos de resoluÃÃo de equaÃÃes diferenciais. Esta ferramenta foi utilizada porque à livre, implementaÃÃo simples, quando comparada com outras linguagens e possui alta performance nas simulaÃÃes. Como estudos de caso, utilizaram-se dados experimentais da secagem convectiva assistida por ultrassom de cubos de maÃà (Malus domestica L. var Royal Gala) com 8 mm de aresta nas seguintes condiÃÃes operacionais: velocidades de secagem: 1, 2, 3 e 5 m/s; temperatura do ar de secagem: 45 ÂC e 60 ÂC; presenÃa e ausÃncia de ultrassom durante a secagem; presenÃa e ausÃncia de etapa de prÃ-tratamento com ultrassom. Os cubos de maÃà dos experimentos tinham, em mÃdia, 25Â1 g. A secagem foi realizada atà que as amostras perdessem 80% da massa inicial. Os parÃmetros, difusividade e coeficiente de transferÃncia de massa, foram ajustados por regressÃo nÃo linear pelo mÃtodo de Levenberg-Marquardt. Os resultados obtidos nas simulaÃÃes mostraram que o modelo implementado à promissor, pois representa bem o processo. Os valores obtidos da difusividade e coeficiente de transferÃncia de massa foram plausÃveis. Analisou-se a influÃncia da velocidade do ar de secagem, da temperatura, da assistÃncia do ultrassom no processo e da utilizaÃÃo de uma etapa de prÃ-tratamento com ultrassom no processo de secagem.
Resende, Ferreira Cháulio de [Verfasser], Michael G. [Akademischer Betreuer] Bader, Michael G. [Gutachter] Bader, and Olaf [Gutachter] Schenk. "Vectorization and Patch-Based Adaptive Mesh Refinement for Finite Volume Solvers / Cháulio de Resende Ferreira ; Gutachter: Michael G. Bader, Olaf Schenk ; Betreuer: Michael G. Bader." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/119723263X/34.
Повний текст джерелаChauveheid, Daniel. "Ecoulements multi-matériaux et multi-physiques : solveur volumes finis eulérien co-localisé avec capture d'interfaces, analyse et simulations." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2012. http://tel.archives-ouvertes.fr/tel-00749651.
Повний текст джерелаMasella, Jean-Marie. "Quelques méthodes numériques pour les écoulements diphasiques bi-fluide en conduites pétrolières." Paris 6, 1997. http://www.theses.fr/1997PA066459.
Повний текст джерелаCioni, Jean-Pierre. "Résolution numérique des équations de Maxwell instationnaires par une méthode de volumes finis." Phd thesis, Université de Nice Sophia-Antipolis, 1995. http://tel.archives-ouvertes.fr/tel-00005612.
Повний текст джерелаGuillemaud, Vincent. "Modélisation et simulation numérique des écoulements diphasiques par une approche bifluide à deux pressions." Phd thesis, Université de Provence - Aix-Marseille I, 2007. http://tel.archives-ouvertes.fr/tel-00169178.
Повний текст джерелаDans un premier temps, on élabore un cadre thermodynamique théorique pour décrire les écoulements liquide-vapeur. Dans ce cadre, on réalise la fermeture du modèle de Baer et Nunziato. De nouvelles modélisations sont proposées pour les termes d'interaction entre les phases. Ces nouvelles modélisations dotent le modèle bifluide à deux pressions d'une inégalité d'entropie. On étudie ensuite les propriétés mathématiques de ce modèle. Sa partie convective hyperbolique se présente sous une forme non-conservative. On étudie tout d'abord la définition de ses solutions faibles. Divers régimes d'écoulement sont alors mis à jour pour le mélange diphasique. Ces différents régimes d'écoulement présentent des analogies avec le comportement fluvial et torrentiel des écoulements en rivière. Les stabilités linéaire et non-linéaire de l'équilibre liquide-vapeur sont ensuite établies. Pour affiner notre description des interactions diphasiques, on étudie pour finir l'implémentation d'un modèle de turbulence, ainsi que l'implémentation d'une procédure de reconstruction pour la densité d'aire interfaciale.
On s'intéresse ensuite à la simulation de ce modèle. Suivant une approche à pas fractionnaires, une méthode numérique est élaborée dans un formalisme Volumes Finis. Pour réaliser l'approximation de la partie convective, diverses adaptations non-conservatives de solveurs de Riemann standard sont tout d'abord proposées. A l'inverse du cadre non-conservatif classique, l'ensemble de ces schémas converge vers une unique solution. Un nouveau schéma de relaxation est ensuite proposé pour approcher la dynamique des transferts interfaciaux. L'ensemble de la méthode numérique se caractérise alors par la préservation des équilibres liquide-vapeur. Dans un premier temps, cette méthode numérique est employée à la comparaison des différentes modélisations bifluides à une et deux pressions. On l'applique ensuite à la simulation des écoulements liquide-vapeur dans les circuits hydrauliques des réacteurs à eau sous pression en configuration accidentelle.
Gressier, Jérémie. "Robustesse et précision des schémas décentrés pour les écoulements compressibles." Phd thesis, Toulouse, ENSAE, 1999. http://oatao.univ-toulouse.fr/2350/1/Gressier_2350.pdf.
Повний текст джерелаTryoen, Julie. "Méthodes de Galerkin stochastiques adaptatives pour la propagation d'incertitudes paramétriques dans les modèles hyperboliques." Phd thesis, Université Paris-Est, 2011. http://pastel.archives-ouvertes.fr/pastel-00795322.
Повний текст джерелаGalié, Thomas. "Couplage interfacial de modèles en dynamique des fluides : application aux écoulements diphasiques." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2009. http://tel.archives-ouvertes.fr/tel-00395593.
Повний текст джерелаFaucher, Eric. "Simulation numérique des écoulements unidimensionnels instationnaires avec autovaporisation." Phd thesis, Université Paris XII Val de Marne, 2000. http://tel.archives-ouvertes.fr/tel-01026372.
Повний текст джерелаErsoy, Mehmet. "Modélisation, analyse mathématique et numérique de divers écoulements compressibles ou incompressibles en couche mince." Phd thesis, Chambéry, 2010. http://tel.archives-ouvertes.fr/tel-00529392.
Повний текст джерелаYousef, Soleiman. "Etude d'estimations d'erreur a posteriori et d'adaptivité basée sur des critères d'arrêt et raffinement de maillages pour des problèmes d'écoulements multiphasiques et thermiques. Application aux procédés de récupération assistée d'huile." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2013. http://tel.archives-ouvertes.fr/tel-00918782.
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