Dissertations / Theses on the topic 'Fluid-dynamic models'
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Durazzo, Gerardo. "Simulation of supply chains dynamics using fluid-dynamic models." Doctoral thesis, Universita degli studi di Salerno, 2013. http://hdl.handle.net/10556/887.
Full textThe aim of thesis is to present some macroscopic models for supply chains and networks able to reproduce the goods dynamics, successively to show, via simulations, some phenomena appearing in planning and managing such systems and, finally, to dead with optimization problems... [edited by author]
XI n.s.
Kachani, Soulaymane, and Georgia Perakis. "A Fluid Model of Dynamic Pricing and Inventory Management for Make-to-Stock Manufacturing Systems." Massachusetts Institute of Technology, Operations Research Center, 2002. http://hdl.handle.net/1721.1/5137.
Full textHolmlund, Petter. "Computational fluid dynamic simulations of pulsatile flow in stenotic vessel models." Thesis, Umeå universitet, Institutionen för fysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-93007.
Full textLivelli, Mark Andrew. "Providing flow parameters for approximate die design models and the improvement and verification of those models using CFD analysis /." Online version of thesis, 2010. http://hdl.handle.net/1850/12222.
Full textKachani, S. (Soulaymane). "Dynamic travel time models for pricing and route guidance : a fluid dynamics approach." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8527.
Full textIncludes bibliographical references (leaves 193-201).
This thesis investigates dynamic phenomena that arise in a variety of systems that share similar characteristics. A common characteristic of particular interest in this work is travel time. We wish to address questions of the type: How long does it take a driver to traverse a route in a transportation network? How long does a unit of product remain in inventory before being sold? As a result, our goal is not only to develop models for travel times as they arise in a variety of dynamically evolving environments, but also to investigate the application of these models in the contexts of dynamic pricing, inventory management, traffic control and route guidance. To address these issues, we develop general models for travel times. To make these models more accessible, we describe them as they apply to transportation systems. We propose first-order and second-order fluid models. We enhance these models to account for spillback and bottleneck phenomena. Based on piecewise linear and piecewise quadratic approximations of the departure or exit flows, we propose several classes of travel time functions. In the area of supply chain, we propose and study a fluid model of pricing and inventory management for make-to-stock manufacturing systems. This model is based on how price and level of inventory affect the time a unit of product remains in inventory. The model applies to non-perishable products. Our motivation is based on the observation that in inventory systems, a unit of product incurs a delay before being sold. This delay depends on the level of inventory of this product, its unit price, and prices of competitors.
(Cont.) The model includes joint pricing, production and inventory decisions in a competitive capacitated multi-product dynamic environment. Finally, we consider the anticipatory route guidance problem, an extension of the dynamic user-equilibrium problem. This problem consists of providing messages to drivers, based on forecasts of traffic conditions, to assist them in their path choice decisions. We propose two equivalent formulations that are the first general analytical formulations of this problem. We establish, under weak assumptions, the existence of a solution to this problem.
by Soulaymane Kachani.
Ph.D.
Ang, Keng Cheng. "A computational fluid dynamic study of blood flow through stenosed arteries /." Title page, table of contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09pha5808.pdf.
Full textHorin, Brett. "Applying Computational Fluid Dynamic Simulations and Predictive Models to Determine Control Schedules for Natural Ventilation." Thesis, Illinois Institute of Technology, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10843192.
Full textThis thesis investigates natural ventilation in building design, culminating in a final project to design optimal ventilation in an underground parking garage. The aim of this research is to explore a method combining computational fluid dynamic (CFD) simulations with neural networks as a means of performing a robust, yet computationally inexpensive simulation. The final project has the objective of simulating an annual operation schedule for louvers at the openings of the garage to achieve a desired airflow rate. Concepts in computational design and building science are explored to fully capture how the geometric domain of architectural modeling can be expressed in computational parameters to successfully perform effective simulations. It was important to make these workflows accessible to architects, so common software in the architecture industry was used. The results of this project support a coupled approach of using CFD simulations and neural networks to predict airflow parameters of interest. Validation CFD simulation results were compared to the results using the neural network and they were in good agreement. Ultimately, this project proves that using this approach is a relatively computationally inexpensive alternative to solely using CFD simulations, making design optimization possible.
Zohora, Fatematuz. "Study of pipe leak fluid dynamic characteristics and their influences on acoustic emission generation." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/207823/1/Fatematuz_Zohora_Thesis.pdf.
Full textCommon, David N. "Development of a system for the measurement of the static bulk modulus of fluids." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17579.
Full textMolale, Dimpho Millicent. "A computational evaluation of flow through porous media." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/686.
Full textNelson, Edward L. "Development of an infrared gaseous radiation band model based on NASA SP-3080 for computational fluid dynamic code validation applications." Thesis, Virginia Tech, 1992. http://hdl.handle.net/10919/42950.
Full textMaster of Science
Kaul, Himanshu. "A multi-paradigm modelling framework for simulating biocomplexity." Thesis, University of Oxford, 2013. https://ora.ox.ac.uk/objects/uuid:a3e6913d-b4c1-49fd-88fb-7e7155de2e2f.
Full textKayabasi, Iskender. "Numerical Investigation Of Characteristics Of Pitch And Roll Damping Coefficients For Missile Models." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614917/index.pdf.
Full textChen, Ru-Ching. "Development of a Supersonic Nozzle and Test Section for use with a Magnetic Suspension System for Re-Entry Aeroshell Models." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1544179612537658.
Full textStell, Brandon. "Thermal-Fluid Dynamic Model of Luge Steels." DigitalCommons@CalPoly, 2017. https://digitalcommons.calpoly.edu/theses/1793.
Full textHosseinpoor, Masoud. "Numerical simulation of fresh SCC flow in wall and beam elements using flow dynamics models." Thèse, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/9808.
Full textRésumé : Récemment, il y a un grand intérêt à étudier les caractéristiques d'écoulement des suspensions dans différentes applications environnementales et industrielles, telles que les avalanches des neiges, les coulées de débris, les systèmes de transport et les processus d’écoulement des matériaux. En ce qui concerne les aspects rhéologiques, la plupart des suspensions, comme le béton frais, se comportent comme un fluide non-Newtonien. Le béton est le matériau de construction le plus largement utilisé dans le monde. En raison de limites qui caractérisent le béton normal en termes de maniabilité et de capacité de remplissage de coffrage, il était nécessaire de développer une nouvelle classe de béton qui peut couler sous son propre poids, en particulier à travers les zones congestionnées du coffrage. Par conséquent, le béton autoplaçant (BAP) est un nouveau matériau de construction qui est de plus en plus utilisé dans les différentes applications. Étant donné sa fluidité élevée de BAP peut être utilisé dans certaines applications particulières, notamment dans la section densément renforcée. Cependant, la fluidité élevée rend le béton plus sensible à la ségrégation des gros granulats pendant l'écoulement (la ségrégation dynamique) et ensuite au repos (ségrégation statique). La ségrégation dynamique peut augmenter lorsque le BAP est coulé sur une longue distance ou en présence d'obstacles. Par conséquent, il est toujours nécessaire d'établir un compromis entre la fluidité, la capacité de passage, et la stabilité du BAP. Ceci doit être pris en considération afin de concevoir le processus de coulée et dosage des mélanges du BAP. Ceci est appelé la conception d'ouvrabilité du BAP. Une conception de maniabilité efficace et non coûteuse peut être achevée à travers la e prévision et l'optimisation de l'ouvrabilité des mélanges de béton pour les procédés de construction sélectionnés, notamment le transport, le pompage, la mise en place, le compactage, la finition, etc. En effet, les formulations de mélange doivent se confirmer à la qualité de la construction demandée, par exemple les niveaux exigés de fluidité, la capacité de passage, la capacité de remplissage, et la stabilité (statique et dynamique). Celui est nécessaire pour développer des outils théoriques afin d’évaluer dans quelles conditions les exigences de qualité de la construction sont satisfaites. Cette thèse est consacrée à la réaliser des simulations analytiques et numériques pour prédire la performance d'écoulement du BAP dans différents procédés de la mise en place du béton. L'objectif spécifique de cette étude consiste à simuler l'écoulement du BAP dans essais empiriques, notamment la boite en L et la boite en T pour évaluer la performance du BAP pendent la mise en place (la fluidité, la capacité de passage, la capacité de remplissage, et la ségrégation dynamique induite par cisaillement ou par gravité). Par conséquent, le BAP est modélisé comme matériau hétérogène. En outre, un modèle analytique est proposé pour prédire la performance à l'écoulement du BAP dans la boite en L en utilisant la théorie de Dam Break. D'autre part, les résultats des simulations numériques de l’écoulement du BAP dans une poutre renforcée sont comparés aux résultats expérimentaux par des profils de surface libres. Les résultats des simulations numériques de BAP coulée (modélisée comme un fluide homogène unique), sont utilisés pour déterminer les zones critiques correspondant à des risques plus élevés de ségrégation et de blocage. Les effets des paramètres rhéologiques, la masse volumique, le contenu des particules, la distribution de barres d'armature, et les interactions particule-barres sur les performances d'écoulement du BAP sont évaluées à l'aide de simulations MFN d’écoulement du BAP par les essais des L-Box et T-box (modélisée comme une matériau hétérogène). Deux nouvelles approches sont proposées pour classifier les mélanges du BAP sur la base de la capacité de remplissage, et les propriétés de performabilité, en fonction de la fluidité, la capacité de passage et de la stabilité dynamique du BAP.
Barney, Anna. "Fluid flow in a dynamic mechanical model of the larynx." Thesis, University of Southampton, 1995. https://eprints.soton.ac.uk/250087/.
Full textHedges, Collin R. "Computational fluid dynamic model of steam ingestion into a transonic compressor." Thesis, Monterey, Calif. : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Jun/09Jun%5FHedges.pdf.
Full textThesis Advisor(s): Gannon, Anthony J. "June 2009." Author(s) subject terms: Computational Fluid Dynamics, Transonic, Compressor, Steam Ingestion, Sanger Rotor. Description based on title screen as viewed on July 10, 2009. Includes bibliographical references (p. 61). Also available in print.
Scharf, Frank H. "Fluid dynamic and kinetic modeling of the near cathode region in thermal plasmas." Berlin Logos-Verl, 2008. http://d-nb.info/994080492/04.
Full textVaitekunas, David A. "A generic dynamic model for crossflow heat exchangers with one fluid mixed /." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59591.
Full textThe solution algorithms are presented in two forms: one-way dependence and two-way dependence: for the constant and variable property version of the model, respectively. Variable time step algorithms are also developed to predict the optimal time step for the finite difference solution. The first one uses a first order predictor method and the second one uses a combined first/second order predictor method.
Finally, the generic model is configured to model the economizer and tubular air preheater of an existing boiler. Steady-state tests validate the numerical solution against available theoretical relations and transient tests investigate the parameters in the solution and time step algorithms to determine their effect on simulation speed and accuracy.
Tucker, Russell P. "Validating a new in vitro model for dynamic fluid shear stress mechanobiology." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:0ea8b159-5cb6-4bf0-9a60-4c580824016a.
Full textKachani, Soulaymane, and Georgia Perakis. "A Fluid Model of Spillback and Bottleneck Phenomena for Determining Dynamic Travel Times." Massachusetts Institute of Technology, Operations Research Center, 2001. http://hdl.handle.net/1721.1/5313.
Full textBolland, Scott William. "FAE : the fluid analogies engine : a dynamic, hybrid model of perception and mental deliberation /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18899.pdf.
Full textWicks, Matthew L. "A modal analysis method for a lumped parameter model of a dynamic fluid system." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-07292009-090406/.
Full textHeß, Julian [Verfasser]. "A consistent debris flow model with intergranular friction and dynamic pore-fluid pressure / Julian Heß." Düren : Shaker, 2019. http://d-nb.info/1196487375/34.
Full textFONTALVO, ERIC MAURICIO GONZALEZ. "ASSESSMENT OF THE DYNAMIC PRESSURE CLOSURE IN 1D TWO-FLUID MODEL FOR VERTICAL ANNULAR FLOW." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=28235@1.
Full textCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Uma análise numérica de escoamento anular vertical ascendente é realizada utilizando o Modelo de Dois Fluidos unidimensional. Para escoamentos verticais, na ausência de mecanismos estabilizadores, o sistema de equações resultante é incondicionalmente mal posto. Dessa forma, visando tornar o sistema de equações bem posto, adicionou-se às equações de quantidade de movimento um termo de pressão dinâmica. Dois modelos disponíveis na literatura são investigados. O primeiro só considera a pressão dinâmica na equação de quantidade de movimento do líquido, a qual é baseada em uma simples expressão para a velocidade da onda na interface. O segundo modelo inclui uma contribuição da pressão dinâmica em ambas equações de quantidade de movimento. No presente trabalho, um terceiro modelo é proposto, o qual é baseado no primeiro modelo, com uma avaliação mais realista da velocidade da onda na interface. O efeito estabilizante da pressão dinâmica é demonstrado através de um rigoroso teste de convergência de malha. As equações de conservação são discretizadas com o método de volumes finitos, com uma integração temporal de primeira ordem e uma discretização espacial TVD de segunda ordem. Tanto o segundo quanto o terceiro modelo considerados apresentaram solução independente da malha. Parâmetros do escoamento como gradiente de pressão, espessura do filme, e variáveis características da onda obtidos numericamente são comparados com dados experimentais disponíveis na literatura, apresentando boa concordância.
A numerical analysis of vertical ascending annular flow with the 1D Two-Fluid model is performed. It is well known that, in vertical flows, the resulting system of equations is unconditionally ill-posed in the absence of stabilizing mechanisms. Therefore, in the present work, to render the system of equations well-posed, modeling of dynamic pressure is included in the momentum equations. Two models available in the literature are examined. The first one only considers the dynamic pressure in the liquid momentum equation, which is based on a simple expression for the interface wave velocity. The second model includes a dynamic pressure contribution to both momentum equations. A third model is proposed based on the first, with a more realistic estimation of the interface wave velocity. A systematic grid convergence test is performed to demonstrate the stabilizing effect of the dynamic pressure. The conservation equations are discretized with the finite volume method, with a first order time integration, and a second order TVD spatial discretization. A grid-independent solution can be found when applying the second and third models considered. Flow parameters such as pressure drop, film thickness and wave characteristics numerically obtained are compared against available experimental data, presenting good agreement.
Chang, Junxia. "Dynamic Scheduling of Open Multiclass Queueing Networks in a Slowly Changing Environment." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4844.
Full textBadioli, Rodolfo. "development of a computational fluid dynamic numerical model for the hydrodynamic forces evaluation on subsea structures." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Find full textYin, Youbing. "MDCT-based dynamic, subject-specific lung models via image registration for CFD-based interrogation of regional lung function." Diss., University of Iowa, 2011. https://ir.uiowa.edu/etd/1112.
Full textAldana, y. Villalobos Gerardo. "Hydraulic behaviour and performance improvement of waste stabilisation ponds using a computational fluid dynamic and a physical model." Thesis, University of Surrey, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402777.
Full textAldana, Gerardo. "Hydraulic behaviour and performance improvement of waste stabilisation ponds (WSPs) using a computational fluid dynamic (CFD) and a physical model." Thesis, University of Surrey, 2004. http://epubs.surrey.ac.uk/843814/.
Full textMcGuire, Jeffrey Robert Aerospace Civil & Mechanical Engineering Australian Defence Force Academy UNSW. "Ignition enhancement for scramjet combustion." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Aerospace, Civil and Mechanical Engineering, 2007. http://handle.unsw.edu.au/1959.4/38748.
Full textLiu, Huolong. "Modeling and control of batch pulsed top-spray fluidized bed granulation." Thesis, De Montfort University, 2014. http://hdl.handle.net/2086/11006.
Full textPiassi, Viviane da Silva Mendes. "Comportamento complexo na formação de bolhas de ar em líquidos." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-05052008-173305/.
Full textWe have investigated the air bubble formation in viscous fluid with some control parameters. We have characterized the sistem using the air flow and the length of the hose that connects the air flow control system and the injector nozzle as control parameters. The hose corresponds to a system dissipative element. We have found period adding routes with and without chaotic behavior, frequency locking, and evidences of homoclinic chaos. We have elaborated mathematic models that emule the experimental data. With cubic model we have explained atractors observerd in a period adding route. With a discontinous model we have elucidated some bubble formation dynamic properties as bistability. We have also developed intergrate-and-fire like model that have led us to results in accordance with the maps properties of Arnold family. We also developed a new experimental technique to study the sistem behavior by measuring the bubbling pressure wave inside the hose.
Guillou, Florian. "CFD Study of the Flow around a High-Speed Train." Thesis, KTH, Aerodynamik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102033.
Full textWillschütz, Hans-Georg, and Eberhard Altstadt. "Development of an Integral Finite Element Model for the Simulation of Scaled Core-Meltdown-Experiments." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-30008.
Full textWillschütz, Hans-Georg, and Eberhard Altstadt. "Development of an Integral Finite Element Model for the Simulation of Scaled Core-Meltdown-Experiments." Forschungszentrum Rossendorf, 2000. https://hzdr.qucosa.de/id/qucosa%3A21827.
Full textLiu, Hua. "A study of the cutting performance in abrasive waterjet contouring of alumina ceramics and associated jet dynamic characteristics." Thesis, Queensland University of Technology, 2004. https://eprints.qut.edu.au/16110/1/Hua_Liu_Thesis.pdf.
Full textLiu, Hua. "A Study of the Cutting Performance in Abrasive Waterjet Contouring of Alumina Ceramics and Associated Jet Dynamic Characteristics." Queensland University of Technology, 2004. http://eprints.qut.edu.au/16110/.
Full textHall, Brenton Taylor. "Using the Non-Uniform Dynamic Mode Decomposition to Reduce the Storage Required for PDE Simulations." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492711382801134.
Full textLopes, Gabriela Cantarelli. "Desenvolvimento de modelo numerico tridimensional e eliptico para o estudo de escoamentos no interior de dutos cilindricos." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266262.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Processos que envolvem escoamentos de fluidos no interior de dutos estão presentes em muitas aplicações industriais. Na indústria petroquímica um desses processos que vem se tornando cada vez mais importante é o craqueamento catalítico de frações pesadas do petróleo, já que as converte em frações leves e mais nobres. Por causa da crescente demanda mundial por gasolina e GLP e à sua alta rentabilidade para uma refinaria de petróleo, unidades de craqueamento catalítico em leito fluidizado (FCC) estão presentes em todo o mundo. Testes experimentais costumam ser usados no estudo dos fenômenos envolvidos nesse processo. Porém esse tipo de análise possui alto custo, que pode ser reduzido com o uso de simulações computacionais em seu estudo inicial. Assim, o objetivo deste trabalho foi desenvolver um modelo tridimensional e elíptico, em linguagem Fortran, capaz de fornecer dados para a análise preliminar de escoamentos no interior de reatores de FCC. Na modelagem desses problemas são usadas equações diferenciais parciais, e essas não possuem solução analítica conhecida, sendo necessário o emprego de métodos numéricos para esse fim. Neste trabalho foi usado o Método dos Volumes Finitos, que tem a função de substituir as equações diferenciais parciais por equações algébricas aplicadas a pequenos volumes de controle finitos pertencentes ao domínio. Uma das maiores dificuldades encontradas no tratamento numérico de escoamentos incompressíveis é a determinação de um campo de pressão que satisfaça a Equação da Continuidade. Esse problema foi resolvido fazendo-se uso da abordagem acoplp.da de solução. Para análise do modelo foram obtidos perfis numéricos de velocidade e pressão para fluidos escoando em regimes laminar e turbulento, que foram validados usando-se os dados obtidos com a solução analítica das equações, por correlações (semi-) empíricas ou por dados experimentais, conforme cada um dos casos. Notou-se que o modelo representa muito bem casos laminares, e gue 11.oS casos turbulentos foi necessário um maior refino da malha próximo a parede do tubo. Também foram feitas simulações para que se pudessem observar as características tridimensionais, elípticas e transientes da modelagem do escoamento. De maneira geral o modelo se mostrou bastante rápido, convergindo em poucas iterações. Palavras-Chave: Fluidodinâmica computacional; dutos cilíndricos; modelo tridimensional e elíptico; método dos Volumes Finitos; solução acoplada; turbulência
Abstract: Processes involving fluid flow in tubes are present in many industrial applications. In petrochemical industry one of these processes that are becoming more and more important is the fluid catalytic cracking of heavy petroleum fractions. This fact is due to the process capacity to convert heavy fractions in light and valuable ones. Because of the increasingly worldwide demand for gasoline and LPG and its high yield for a petroleum refinery, fluid catalytic cracking (FCC) units are present in the whole world. Experimental tests are used in the study of the phenomena involved in this processo However this kind of analysis has high cost which can be reduced by using computational simulations in its initial study. Thus, the aim of this work was the development of a three-dimensional and elliptical mo dei in Fortran language in order to provide data for fluid flow preliminary analysis in FCC reactors. Partial differential equations were used in the modeling of these problems. These equations do not have known analytical solution, being necessary therefore the use of numerical methods. In this work the Finite Volume Method were applied with this purpose. This method has as a role to substitute the partial differential equations of the mo dei for algebric equations applied to small finite control volumes of the domain. One of the biggest difficulties found in the numerical treatment of incompressible fluid flows is the determination of apressure field that satisfies the Continuity Equation. This problem was solved using the coupled solution approach. For model analysis, numerical velocity and pressure proJ:iles for laminar and turbulent flows were obtained, that had been validated using the data obtained through the analytical solution of the equations, by empirical correlations or by experimental data, according to each one of the cases. The model represented well laminar cases, and in the turbulent ones the mesh had to be more refined near the tube wall. Other simulations were performed, in aQalyzing the three-dimensional, elliptical and transient model characteristics. In general, the mo dei was very fast, converging in a few interations. Keywords: Computational fluid dyn~mic; cylindrical ducts; three-dimensional and elliptical model; Finite Volume Method; coupled solution; turbulence
Mestrado
Desenvolvimento de Processos Químicos
Mestre em Engenharia Química
Kestering, Daniel Augusto. "Simulação fluidodinâmica de um leito fluidizado empregando correlações de arrasto gás-sólido ajustadas por valores experimentais." Universidade do Vale do Rio dos Sinos, 2016. http://www.repositorio.jesuita.org.br/handle/UNISINOS/6093.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares
A investigação dos modelos de arrasto gás-sólido é fundamental para se obter bons resultados de fluidização utilizando dinâmica dos fluidos computacional. A tecnologia de fluidização é muito utilizada para conversão térmica de combustíveis sólidos e tem como principal vantagem a boa mistura entre gás e sólido. O presente trabalho utiliza dois softwares para simulação de leitos fluidizados, MFIX e Ansys Fluent, para comparar os modelos de arrasto de Syamlal e O`Brien (1987) e Di Felice (1994). A abordagem utilizada para modelagem do problema é o modelo de dois fluidos (Two Fluid Model, TFM), juntamente com a teoria cinética para escoamento laminar (Kinetic Theory for Granular Flow, KTGF). Um método para ajuste do modelo de DF (DI FELICE, 1994), baseado no trabalho de Esmaili e Mahinpey (2011), é sugerido, assim como o modelo de SO (SYAMLAL; O`BRIEN,1987) é ajustado utilizando dados em condição de mínima fluidização. Foram conduzidos experimentos para obtenção de velocidade e fração de vazios em condição de mínima fluidização a fim de ajustar ambos os modelos. As partículas utilizadas nos experimentos foram esferas de vidro de 1,21 mm, 0,8 mm e areia de fundição de 0,29 mm. O método proposto representa de forma adequada os dados obtidos em mínima fluidização das três partículas. Com os modelos de arrasto ajustados, simulações numéricas em regime de fluidização foram conduzidas em domínio bidimensional e tridimensional. Os resultados obtidos nestas simulações apresentam boa concordância com resultados experimentais em queda de pressão do leito e borbulhamento. Concomitantemente, um código para obtenção de modelo de arrasto utilizando o algoritmo EMMS/Bubbling foi desenvolvido e simulações numéricas bidimensionais foram conduzidas, para teste e validação. Os resultados do código mostram que o modelo segue a mesma tendência de Shi, Wang e Li (2011), que desenvolveram o modelo EMMS/Bubbling.
The investigation of gas-solid drag models is a key to obtain good results of fluidization by using computational fluid dynamic tools. The fluidization technology is used for solid fuel thermal conversion and its main advantage is the high gas-solid mixture. The present effort uses two software for fluidized beds simulation, MFIX and Ansys Fluent, in order to compare the drag models of Syamlal and O`Brien (1987) and Di Felice (1994). Two Fluid Model is the approach used to model together with Kinetic Theory for Granular flow. A method to adjust DF drag model (DI FELICE, 1994), based on Esmaili and Mahinpey (2011), is suggested, as well as SO drag model (SYAMLAL; O’BRIEN, 1987) is adjusted using data obtained from minimum fluidization condition. Experiments were realized to obtain velocity and void fraction at minimum fluidization condition in order to adjust both models. Glass beads with diameter of 1,21 mm and 0,8 mm and sand with diameter of 0,29 mm were used on experiments. The purposed method fits the data obtained on minimum fluidization condition of the three particles, in accordance with experimental data. With the models adjusted, numerical simulation were conducted using drag models for two- and three-dimensional domain. The results of this simulations agrees with experimental data of pressure drop and bubble formation. Simultaneously, a code to obtain a drag model using EMM/Bubbling algorithm was developed and numerical simulation were conducted. Results of EMMS show that the model have the same tendency of results of Shi, Wand and Li (2011), who developed EMMS/Bubbling model.
Tavano, Matteo. "Seismic response of tank-fluid systems: state of the art review and dynamic buckling analysis of a steel tank with the added mass method." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/3006/.
Full textBraun, Meire Pereira de Souza. "Modelagem do particulado em sistemas gás-sólido utilizando o modelo de dois fluidos e o método dos elementos discretos." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18149/tde-16092013-160059/.
Full textThe purpose of the present study is to perform a theoretical study and develop numerical simulations involving dynamic in gas-solid systems. The focus of the work is the modeling of particulate matter using continuous models based on soil mechanics and the kinetic theory of granular flows (large systems with many particles, Eulerian formulation - Finite Volume) and discrete models based on physical characteristics of the particles (intermediate systems and limited number of particles, Lagrangian formulation - Discrete Element Method). It is proposed a new approach to determine the normal spring stiffness coefficient of the linear model through the numerical solution for the overlap between particles in non-linear models. The linear spring stiffness is determined using an equivalence between the linear and the non-linear models. It is used the MFIX computational code to perform numerical simulations of the dynamics of gas-solid systems. It is analyzed the processes of fluidization, mixing and particle segregation and the influence of drag correlations. The proposed approach for normal spring stiffness coefficient is applied in the numerical simulations of two problems: single freely falling particle and bubbling fluidized bed. The results were compared with numerical and experimental data from literature.
Najafi, Zahra. "Development of New Treatment Modalities for Kidney/Ureter Stones." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1435153573.
Full textDaepp, Hannes Gorkin. "Development of a multi-platform simulation for a pneumatically-actuated quadruped robot." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45927.
Full textLecuyer-Le, Bris Romain. "Modélisation numérique et expérimentale de la captation d'énergie houlomotrice : application aux essais à échelle réduite en bassin." Thesis, Brest, 2022. http://theses-scd.univ-brest.fr/2022/These-2022-SML-Mecanique_genie_mecanique_mecanique_des_fluides_et_energetique-LECUYER_LE_BRIS_Romain.pdf.
Full textThe behaviour of wave energy converters (WEC) is non-linear and complex to model accurately, especially due to the fluid–structure interaction and the randomness of the wave. The ability of a WEC to recover some of the wave energy depends on the control strategy used and the reliability of the behaviour model. Numerical computation time must remain reasonable in order to allow real–time control. In this context, perfect fluid calculations are used to model the fluid-structure interaction at first order. This diffraction–radiation approach highlights the delay functions of the system, a detailed analysis of which has been carried out in this work and illustrated on a reference case. This thesis proposes to establish a method applicable to the modelling of any type of multi-body WEC. The formulation of the hydrodynamic forces resulting from the assumptions of perfect fluid is then supplemented with semi–empirical terms in order to take into account non–linear effects. The viscous forces represented are particularly influential in the vicinity of the motion resonances. This method also allows the integration of experimental data into the numerical model. Experimental work was therefore carried out in order to understand, quantify and integrate the effects observed experimentally for an anchored body into the numerical model. Finally, elements in favor of an experimental campaign for a two-body system are presented
Tissot, Gilles. "Réduction de modèle et contrôle d'écoulements." Thesis, Poitiers, 2014. http://www.theses.fr/2014POIT2284/document.
Full textControl of turbulent flows is still today a challenge in aerodynamics. Indeed, the presence of a high number of active degrees of freedom and of a complex dynamics leads to the need of strong modelling efforts for an efficient control design. During this PhD, various directions have been followed in order to develop reduced-order models of flows in realistic situations and to use it for control. First, dynamic mode decomposition (DMD), and some of its variants, have been exploited as reduced basis for extracting at best the dynamical behaviour of the flow. Thereafter, we were interested in 4D-variational data assimilation which combines inhomogeneous informations coming from a dynamical model, observations and an a priori knowledge of the system. POD and DMD reduced-order models of a turbulent cylinder wake flow have been successfully derived using data assimilation of PIV measurements. Finally, we considered flow control in a fluid-structure interaction context. After showing that the immersed body motion can be represented as an additional constraint in the reduced-order model, we stabilized a cylinder wake flow by vertical oscillations
Wahl, Jean-Baptiste. "The Reduced basis method applied to aerothermal simulations." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAD024/document.
Full textWe present in this thesis our work on model order reduction for aerothermal simulations. We consider the coupling between the incompressible Navier-Stokes equations and an advection-diffusion equation for the temperature. Since the physical parameters induce high Reynolds and Peclet numbers, we have to introduce stabilization operators in the formulation to deal with the well known numerical stability issue. The chosen stabilization, applied to both fluid and heat equations, is the usual Streamline-Upwind/Petrov-Galerkin (SUPG) which add artificial diffusivity in the direction of the convection field. We also introduce our order reduction strategy for this model, based on the Reduced Basis Method (RBM). To recover an affine decomposition for this complex model, we implemented a discrete variation of the Empirical Interpolation Method (EIM) which is a discrete version of the original EIM. This variant allows building an approximated affine decomposition for complex operators such as in the case of SUPG. We also use this method for the non-linear operators induced by the shock capturing method. The construction of an EIM basis for non-linear operators involves a potentially huge number of non-linear FEM resolutions - depending on the size of the sampling. Even if this basis is built during an offline phase, we usually can not afford such expensive computational cost. We took advantage of the recent development of the Simultaneous EIM Reduced basis algorithm (SER) to tackle this issue
Poyi, Gwangtim Timothy. "A novel approach to the control of quad-rotor helicopters using fuzzy-neural networks." Thesis, University of Derby, 2014. http://hdl.handle.net/10545/337911.
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