Dissertations / Theses on the topic 'Darcy's Law'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 44 dissertations / theses for your research on the topic 'Darcy's Law.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Welsh, Wendy Denise, and wendywelsh@yahoo com au. "Groundwater balance modelling with Darcy's Law." The Australian National University. Faculty of Science, 2007. http://thesis.anu.edu.au./public/adt-ANU20070703.165654.
Full textPunpocha, Mahosut. "Flow in a porous medium driven by differential heating." Thesis, City University London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340050.
Full textHood, Jonathan Patrick. "Changes in Oriented Strandboard Permeability During Hot-Pressing." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/10049.
Full textMaster of Science
Arimoto, Shinichi. "Numerical method for coupled analysis of Navier-Stokes and Darcy flows." Kyoto University, 2018. http://hdl.handle.net/2433/232352.
Full text0048
新制・課程博士
博士(農学)
甲第21151号
農博第2277号
新制||農||1059(附属図書館)
学位論文||H30||N5125(農学部図書室)
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 村上 章, 教授 川島 茂人, 教授 藤原 正幸
学位規則第4条第1項該当
Franks, Susan J. "Mathematical modelling of tumour growth and stability." Thesis, Nottingham Trent University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366363.
Full textTangpithakkul, Rawee. "Study of permeability of pavement base materials." Ohio University / OhioLINK, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1184344573.
Full textZafar, Saleem. "Strength and hydraulic conductivity characteristics of roller compacted concrete." Ohio : Ohio University, 1997. http://www.ohiolink.edu/etd/view.cgi?ohiou1184617589.
Full textMattos, Tiago Souza. "Avaliação do impacto da substituição de pastagem por eucalipto na recarga de aquífero freático." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-14082015-144441/.
Full textHistorically forest plantations are associated with intense debate about its impact on soil water dynamics or groundwater. Thus, the objective of this study was to evaluate the potential impacts of land cover change of pasture to eucalyptus on the groundwater in an outcrop zone of the Guarani Aquifer System. The study area is located in the Ribeirão da Onça watershed, located in the municipality of Brotas, in the center-east of the state of São Paulo. To assess the impact of land cover change, I used two methods: i. iWTF and ii. Darcy. From these methods, we estimated groundwater recharge rates, lateral flow, water storage variation and deep percolation. Furthermore, I obtained the water table variation, saturated thickness and horizontal hydraulic gradient into the aquifer in the study area. During the hydrological years 2005-2011, the direct recharge through the results of iWTF method varied between 256 and 876 mm, equivalent to 21% and 51% of the corresponding annual precipitation. After 2011, with the land cover change of pasture to eucalyptus, the direct recharge was computed at about 210 mm (2012) and 147 mm (2013), equivalent to 13% and 10% of the annual precipitation. I did not find significant difference in the annual precipitation in these years compared to the historical mean. Therefore, my findings have shown that the decrease of direct recharge are associated to the land cover change of pasture to eucalypts. The decrease in direct recharge leads to the reduction of saturated thickness, the water level variation, horizontal hydraulic gradient, lateral flow and annual storage. Moreover, it can be seen that the forest plantation has influenced the pasture area, adjacent to the plantation. It has been observed that influence through the existence of cross flow toward the forest plantation, which has high storage, especially in the dry season. The results indicate that the eucalyptus plantation significantly affected the seasonal and annual behavior of the water balance in the study area.
Erdmann, Robert Gerald. "Image-Based Numerical Simulation of Stokes Flow in Porous Media." Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/195724.
Full textHendrick, Angus Greer. "Effects of domain size on transverse permeability through random arrays of cylinders." Thesis, The University of Arizona, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3592730.
Full textResearchers using Darcy's law to model flow in porous media must satisfy the requirement for sufficient scale separation between the pore scale and the model scale. This requirement is analogous to that for any continuum model, where application is restricted to scales larger than the underlying discrete structure. In the case of Darcy's law when the model scale becomes too small, the measurement of the permeability—the material property required to close the relationship—becomes polluted by the boundary conditions, either physical or numerical. The requirements for adequate scale separation to obtain permeability measurements (also known as satisfying the conditions for a representative elementary volume, or REV, for permeability) have not been previously reported. Likewise, the behavior of Darcy models when applied at sub-REV length scales has not been reported.
Here, the results of Stokes simulations of transverse flow in 90,000 sequential random packings of monodisperse cylinders at a variety of liquid fractions and averaging-volume sizes show that approximately 200 cylinders must be present in an averaging volume before the effects of periodic boundary conditions on the Stokes simulations (the conventional choice for permeability measurements using Stokes flow) are no longer evident in the measured permeability. Direct comparisons between flow predictions from a two-dimensional, tensor-based Darcy model and a Stokes model for additional 10,000 domains show that the Darcy model is an unbiased predictor of the flow distribution in the system, even when the permeability is expected to contain boundary-condition artifacts. Though unbiased, the Darcy models do show considerable reduction in accuracy as the model scale shrinks toward the pore scale, with significant declines observed after the side length of a square averaging volume reaches 10 times the cylinder diameter. Finally, a novel approach for visualizing flows using the linear properties of the Stokes equations shows how the periodic boundary conditions affect the flow, and motivates the development of a generalized approach for obtaining permeability that does not require periodic boundary conditions. Modest improvements in the Darcy model relative to the actual Stokes flow result when the new approach is used to obtain permeability at small averaging volumes.
Yamashita, Hiroshi, Shingo Satake, and Kazuhiro Yamamoto. "Microstructure and particle-laden flow in diesel particulate filter." Elsevier, 2009. http://hdl.handle.net/2237/20047.
Full textCarling, Gregory T. "The rate and timing of direct mountain front recharge in an arid environment, Silver Island Mountains, Utah." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2187.pdf.
Full textMat, Isa Zaiton. "Mathematical modelling of fumigant transport in stored grain." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/75420/1/Zaiton_Mat%20Isa_Thesis.pdf.
Full textSita, Ram Rao K. V. "Wall Effects In Packed Beds." Thesis, Indian Institute of Science, 1994. https://etd.iisc.ac.in/handle/2005/126.
Full textSita, Ram Rao K. V. "Wall Effects In Packed Beds." Thesis, Indian Institute of Science, 1994. http://hdl.handle.net/2005/126.
Full textBernales, chavez Braulio. "Modélisation de l'hydrodynamique et des transferts dans les procédés de filtration membranaire." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4779/document.
Full textConcentration polarization of solute at the membrane surface, because of osmotic pressure effects, is an important phenomenon that can cause substantial reductions in permeation. To understand these phenomena: we first analyze the filtration process for a pure solvent, imposing the influence of the driving pressure on permeation at the membrane. We obtain accurate analytical solutions for the flow fields. We then derive an analytical solution that coupled hydrodynamics to mass transfer for filtration systems working in a situation of High Pressure and Low Recovery. Second, we develop a numerical model that incorporates both physical aspects: the dependency of pressure on permeation and the influence of concentration polarization and their related osmotic effects in the effective pressure at the membrane. For that, the numerical approach solves the solute conservation equation coupled with the Navier-Stokes equations under the steady Prandtl approximation. The solution of the system is performed using a finite difference method of order 2. The validity of this approach is successfully demonstrated with the previous analytical solutions for hydrodynamics, as well as for the coupling with mass transfer. We then test the influence of the main operating parameters (inlet concentration, axial flow rate, operating pressure and membrane permeability) on the performance of the filtration system and compare the results with other numerical models that takes into account concentration polarization phenomenon. Finally, the validity of this model is quantitatively well-proved when using the reported data resulting from reverse osmosis experiments
Bailly, David. "Vers une modélisation des écoulements dans les massifs très fissurés de type karst : étude morphologique, hydraulique et changement d'échelle." Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT027H/document.
Full textKarstic aquifers contain large subsurface water resources. These aquifers are complex and heterogeneous on a large range of scales. Their management requires appropriate numerical tools and approaches. Various tools and numerical methodologies have been developed to characterize andmodel the geometry and hydraulic properties of karstic aquifers, more generally, of highly fissured 2D and 3D porous media. In this study, we emphasize morphological characterization, and we analyze hydrodynamic behavior through the concept of upscaling ("second upscaling"). Concerning the morphology of fissured porous media, several axes are explored : random media, composite random Boolean media with statistical properties, and morphogenetic models. Hydrodynamic upscaling is developed using the macro-permeability concept. This upscaling method is based on either Darcy's linear law, or on a linear/quadratic combination of Darcy's and Ward-Forchheimer's quadratic law (inertial effects). First, the study focuses on Darcy's linear head loss law, and Darcian effective permeabilities are calculated numerically in terms of volume fractions of fissures and "fissure/matrix" permeability contrasts. The results are analysed and compared with analytical results and bounds. A special study of percolation and quasi-percolation effects, for high contrasts, leads to defined three critical fractions. These critical fractions are "connected" to percolation thresholds. Secondly, in order to consider inertial effect in fissures, the study is extended to a local law with a quadratic velocity term (Darcy/Ward-Forchheimer). Then, an equivalent nonlinear macroscopic permeability is defined and analysed using a generalized inertial model (linear/power). Finally, the large scale hydraulic anisotropy of fissured medium is studied, in terms of directional permeabilities, using an "immersion" numerical method
Dib, Serena. "Méthodes d'éléments finis pour le problème de Darcy couplé avec l'équation de la chaleur." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066294/document.
Full textIn this thesis, we study the heat equation coupled with Darcy's law by a nonlinear viscosity depending on the temperature in dimension d=2,3 (Hooman and Gurgenci or Rashad). We analyse this problem by setting it in an equivalent variational formulation and reducing it to an diffusion-convection equation for the temperature where the velocity depends implicitly on the temperature.Existence of a solution is derived without restriction on the data by Galerkin's method and Brouwer's Fixed Point. Global uniqueness is established when the solution is slightly smoother and the dataare suitably restricted. We also introduce an alternative equivalent variational formulation. Both variational formulations are discretized by four finite element schemes in a polygonal or polyhedral domain. We derive existence, conditional uniqueness, convergence, and optimal a priori error estimates for the solutions of the three schemes. Next, these schemes are linearized by suitable convergent successive approximation algorithms. We present some numerical experiments for a model problem that confirm the theoretical rates of convergence developed in this work. A posteriori error estimates are established with two types of errors indicators related to the linearisation and discretization. Finally, we show numerical results of validation
Zhang, Andi. "Numerical investigation of multiphase Darcy-Forchheimer flow and contaminant transport during SO₂ co-injection with CO₂ in deep saline aquifers." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49065.
Full textQin, Xiaowen. "Modeling Study of Pyrolysis of Composite Materials : Application to Wood and Carbon/Epoxy Composite." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2021. http://www.theses.fr/2021ESMA0006.
Full textComposite materials occupy a critical position in industrial applications or more broadly in our daily life. Synthetic composites substitute metallic materials due to their lightweight properties to achieve identical mechanical performance. They are widely used in the fields of energy transportation and storage. Natural composites (wood) are also widely used, especially in construction industry. The disadvantage of these materials involves the disability in maintaining their mechanical characteristics in a fire scenario, and the study of their fire resistance is therefore a major issue. This thesis aims to develop a mathematical model of thermal decomposition of composite materials subjected to different heating conditions. The simulations of different cases of thermal decomposition make it possible to study the interactions among the processes of heat and mass transfer as well as chemical reactions within the solid. The developed 3D model describes the gas transport within the pores of materials at the Darcy scale. Thermal conductivity is formulated in a tensor form allowing the definition of heat transfer in three directions of the domain. For the two types of materials, a multi-step reaction scheme is defined to describe the pyrolysis process. The cone calorimeter tests used to validate the model were carried out under an inert atmosphere (Nitrogen) which makes it possible to eliminate the presence of flame on the material surface as well as the heterogeneous reactions which can occur in the presence of oxygen. Therefore, the defined boundary conditions are quite simple and well-controlled to characterize without considering the unsteady flame. Pyrolysis gasses are assembled into inert gas, therefore, the gas reactions in the pore are neglected and the local thermal equilibrium between the solid and gas phase is assumed. The implementation of this pyrolysis model follows a scale separation process with two types of materials. The different heat and mass transfer processes, as well as chemical reactions, are studied separately to avoid the interactions, then the model is reconstructed to take these interactions into account. The pyrolysis behavior is firstly studied at a "0D" scale to develop the part of chemical reactions. The thermogravimetric analysis (TGA) is used at this scale and related experiments are conducted at different heating rates under an inert atmosphere. At this scale, only the chemical reactions are involved with known kinetics, and the heat and mass transport within the solid can be neglected with homogeneous temperature distribution. The different chemical reactions are described with the Arrhenius-type equation. The kinetic parameters are calculated by the inverse modeling method. The influence of the heating rate on the pyrolysis process is analyzed and 2D simulations are conducted at two heating rates to analyze the evolution of thermal and pressure gradients within the solid. The phenomena of heat and mass transport are considered and studied by bench-scale experiments which are conducted in the cone calorimeter. The corresponding simulations are implemented under two heat flux. The interactions among the heat and mass transport as well as chemical reaction processes are studied by analyzing the local time and length scales to identify what are the dominant phenomena through the whole pyrolysis process
Zhang, Wenxiang. "Optimization of protein concentration from alfalfa juice by high shear rate dynamic filtration." Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2281/document.
Full textAlfalfa leaf proteins extracted from plants are an important protein source. As an environmentally friendly separation technology with high productivity and low cost, membrane filtration was used to separate and concentrate leaf protein from alfalfa juice. However membrane fouling seriously reduces flux and protein separation and is an important limitation in the application of membrane filtration. To improve protein recovery and fouling control, dynamic shear-enhanced membrane filtration with high shear rate on membrane surface and excellent anti-fouling capacity was used for alfalfa juice filtration in this work. In order to optimize filtration process, filtration mode and operation parameters were investigated to reduce membrane fouling and improve separation performance. Then, alfalfa wastewater was also treated by dynamic shear-enhanced membrane filtration to recycle proteins. Furthermore, the fouling mechanism was studied and served as a valuable evaluation for fouling strategies. In this study, process optimization including “Filtration mode” and “Operation parameters” was studied to improve protein recovery and fouling control. In “Filtration mode”, three types of filtration modules (dead end filtration using laboratory Amicon cell (DA), dynamic cross filtration using rotating disk module (CRDM) and dead end filtration using rotating disk module (DRDM)) were used to investigate the filtration performance. As for “Operation parameters”, the operation parameters including membranes (ultrafiltration (UF) and microfiltration (MF)), rotating speed, temperature and transmembrane pressure (TMP) were studied to optimize the filtration process. Flux behavior (permeate flux and flux decline), separation performance (clarification and concentration capacity), membrane cleaning efficiency (permeability recovery) and productivity in full recycling tests and concentration tests were utilized to evaluate the various operation strategies. In addition, alfalfa wastewater was treated by UF membrane, while waste proteins were recycled. Fouling mechanism for alfalfa juice filtration was investigated. The fouling process showed significantly stepwise multisite patterns. Based on Darcy’s law, the stepwise multisite Darcy’s law model (SMDM) was proposed to better describe and understand the fouling process. The effects of feed composition, membrane and hydraulic conditions played an important role in stepwise fouling process. Moreover, the resistance coefficient and compressibility for different steps and sites were calculated to explain the complex fouling process and estimate the efficiency of flux decline control strategies. Besides, a series of long tests were utilized to study flux decline and membrane fouling at various fouling step process. These results can be used to understand the protein recovery and fouling control during shear-enhanced membrane filtration process of alfalfa juice. They have important implications for process design of membrane technology in industrial scale
Söderberg, Karolina. "Utredning av igensättningsproblematik i markfilter av sorbtionstyp vid Gräfsåsens avfallsanläggning." Thesis, Mittuniversitetet, Avdelningen för ekoteknik och hållbart byggande, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-29261.
Full textFilters for treatment of leachate have been developed over the years to hold tailor-made properties for the treatment of leachate. Leachate contains a variety of pollutants, which depends on the waste upon the landfill. In sorption-filters the traditional filter’s mechanical ability to remove particles and biological ability to break down organic material, is combined with one or several sorbents which act to precipitate or trap contaminants. However, it is rather common that these types of filters suffer from clogging which result in reduction of the filter’s capacity and lifetime. At the landfill in Gräfsåsen, belonging to the municipality of Östersund, a sorption filter developed by a consultant was installed in 2013, which was estimated to have a lifespan of 10-15 years. When installed, the capacity of the filter was lower than expected and also decreased rapidly over time. The filter media had to be redesigned after a couple of months in operation, but the problem with clogging/low capacity remained. This thesis was shaped to investigate the causes of the clogging problem of the filter at Gräfsåsen and to suggest improvements. The study consisted mainly of two parts, one part consisted of interpreting and comparing test results and characterize the leachate from a study of leachate from IVL (Swedish Environmental Research Institute). The second part consisted of controlling the consultant’s sizing and compare with other models for sizing filters. The analytical results and calculations were supplemented with a practical test to filter leachate and tap water in separate filter columns, designed with the same proportions and materials as the existing filter. The purpose of the filtering columns was to assess the material's hydraulic capacity and to examine whether there were any differences in the flow times of the leachate and tap water. The filtering showed that the degree of compaction of the filter material is of great importance for the permeability, no conclusions regarding the water quality’s impact could be drawn. The characterization indicated that the leachate in Gräfsåsen contained high concentrations of BOD, POC, aluminum, sulfur, calcium and phosphorus. Analyzes and comparisons collectively indicated that metal oxides and carbonates precipitated in the filter. The calculations showed that the filter is dimensioned for an average flow rate less than what was assessed appropriate. The hydraulic conductivity of the filter material was lower than the consultant's recommendations, which in practice meant that the capacity of the filter was a third of the flow it intended to be designed for.
Alastal, Khalil. "Ecoulements oscillatoires et effets capillaires en milieux poreux partiellement saturés et non saturés : applications en hydrodynamique côtière." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0039/document.
Full textIn this thesis, we study hydrodynamic oscillations in porous bodies (unsaturated or partially saturated), due to tidal oscillations of water levels in adjacent open water bodies. The focus is on beach hydrodynamics, but potential applications concern, more generally, time varying and oscillating water levels in coupled systems involving subsurface / open water interactions (natural and artificial beaches, harbor dykes, earth dams, river banks, estuaries). The tidal forcing of groundwater is represented and modeled (both experimentally and numerically) by quasi-static oscillations of water levels in an open water reservoir connected to the porous medium. Specifically, we focus on vertical water movements forced by an oscillating pressure imposed at the bottom of a soil column. Experimentally, a rotating tide machine is used to achieve this forcing. Overall, we use three types of methods (experimental, numerical, analytical) to study the vertical motion of the groundwater table and the unsaturated flow above it, taking into account the vertical head drop in the saturated zone as well as capillary pressure gradients in the unsaturated zone. Laboratory experiments are conducted on vertical sand columns, with a tide machine to force water table oscillations, and with porous cup tensiometers to measure both positive pressures and suctions along the column (among other measurement methods). Numerical simulations of oscillatory water flow are implemented with the BIGFLOW 3D code (implicit finite volumes, with conjugate gradients for the matrix solver and modified Picard iterations for the nonlinear problem). In addition, an automatic calibration based on a genetic optimization algorithm is implemented for a given tidal frequency, to obtain the hydrodynamic parameters of the experimental soil. Calibrated simulations are then compared to experimental results for other non calibrated frequencies. Finally, a family of quasi-analytical multi-front solutions is developed for the tidal oscillation problem, as an extension of the Green-Ampt piston flow approximation, leading to nonlinear, non-autonomous systems of Ordinary Differential Equations with initial conditions (dynamical systems). The multi-front solutions are tested by comparing them with a refined finite volume solution of the Richards equation. Multi-front solutions are at least 100 times faster, and the match is quite good even for a loamy soil with strong capillary effects (the number of fronts required is small, no more than N≈ to 20 at most). A large set of multi-front simulations is then produced in order to analyze water table and flux fluctuations for a broad range of forcing frequencies. The results, analyzed in terms of means and amplitudes of hydrodynamic variables, indicate the existence, for each soil, of a characteristic frequency separating low frequency / high frequency flow regimes in the porous system
RASOLOARIJAONA, MAMY NIRINA. "Non-linearites de la loi de darcy : etudes theorique, numerique et experimentale." Grenoble 1, 1993. http://www.theses.fr/1993GRE10124.
Full textBergman, Karin, Linn Berkelund, Maria Nylander, Malin Olsson, and Terese Renström. "HYDROGEOLOGISKA FÖRHÅLLANDEN I GÄVLEÅSEN : Analys av stabila syreisotoper och kemiska parametrar samt beräkning av flöden i Gävleåsen." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-295020.
Full textPegaz-fiornet, Sylvie. "Etude de modèles pour la migration des hydrocarbures dans les simulateurs de bassin." Thesis, Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10049.
Full textHydrocarbon migration modeling in sedimentary basins aims to localize and to quantify hydrocarbon accumulations in geological formations in order to estimate their petroleum potential. In this thesis, we study “Darcy” migration models and also simplified migration models such as “ray-tracing” and “invasion percolation”; the purpose is to conduct a critical analysis and to offer improvements while providing a guide for a relevant use on case studies.We start by a review of migration mechanisms from the pore scale to the basin scale, then we present each model.In a following part, we propose two invasion percolation algorithms: the first one is suited to structured grids, the second one allows to take better account of unstructured grids.In a third part, we take an interest in the comparison between the different models and particularly between “Darcy” and “invasion percolation” approaches. First we devote our attention to numerical aspects supported by several use cases; then we realize a formal comparison by studying the asymptotic limit of the “Darcy” model large time solution. Afterwards, we present several applications including the study of a 3D real case in complex geometry.Finally, we conclude this work with two articles. The first one shows an evolution of “Darcy” models by using the method of local grid refinement with an illustration on a case study from northern Kuwait. The second one synthesizes the main results on “Darcy” and “invasion percolation” methods
Keiser, Ludovic. "Formation et déplacement de gouttes confinées : Instabilités et dynamiques." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC080/document.
Full textBiphasic flows in porous media generally lead to the emulsification of one phase into the other. This may be due to several phenomena, such as viscous fingering or pure capillary instabilities. In this experimental thesis, we study a particular emulsifying phenomenon of oil in a model porous medium, as well as the transport of the produced droplets in confined regions. In the first part of the manuscript, the Rayleigh-Taylor instability is revisited in a wedge formed between two centimetric glass plates. The gradient of confinement leads to a capillary force not present in the canonical Rayleigh-Taylor instability. This new force can stabilize liquid layer above air submitted to gravity. The threshold of the instability, the characteristic wavelength and the growth rate are captured by a linear stability analysis of the interface. This characterization of the confinement-induced capillary force drove us to the study of a pure capillary instability occurring when a wetting liquid migrates toward the most confined regions of a wedge, initially filled with a less wetting liquid. The gradient of confinement generates a destabilizing force, leading to the complete inversion of the position of both phases. The less wetting liquid is fully emulsified and the produced droplets are convected towards the less confined regions. A linear stability analysis of the interface here again predicts the characteristic size of the droplets. However, the measured growth rates are not in agreement with the model, based on the Darcy law. This suggests a localization of viscous dissipation in the contact lines displaced during the development of the instability. Another source of viscous dissipation can be in the deposited lubrication films. Those "non-Darcian" dynamics motivated the second part of this thesis, which focuses on the motion of very viscous and non-wetting droplets confined in water. In this configuration, the lubrication film of water between the drop and the substrate ensures the localization of viscous dissipation in those films of low viscosity. This favors the extremely high mobility of the droplets. We also show that wall roughness may induce a thinning of these lubrication films. We shed light on the intricate coupling between viscous friction at the front of the drop and in its bulk. In a last part of this work, we study the capillary instability occurring when a binary droplet of water and alcohol is deposited at the surface of a vegetable oil bath. The dominant evaporation of alcohol at the surface of the drop induces local variations of surface tension. Interfacial Marangoni flows are thus observed, leading to the spectacular destabilization of the spreading droplet
Chevalier, Thibaud. "Écoulements de fluides à seuil en milieux confinés." Phd thesis, Université Paris-Est, 2013. http://tel.archives-ouvertes.fr/tel-00903850.
Full textCopol, Cédrick Nicolas. "Etudes mathématiques et numériques pour la modélisation des systèmes hydrothermaux. Applications à la géothermie haute énergie." Thesis, Antilles, 2016. http://www.theses.fr/2016ANTI0093/document.
Full textThe purpose of our study is to model a geothermal reservoir. When geothermal reservoirs are assumed to be composed of pure water, the transfer of mass and energy is classically described by two balance equations: the mass balance equation and the energy balance equation. In addition to those equations, fluid velocity is classically given by the Darcy law while thermodynamic properties, inferred from theoretical or empirical equations of state, are used to close the mathematical system. Once this system is closed, there exist different solutions. The first one is to solve for pressure and temperature with a variable switch to saturation in the two-phase region (e.g. TOUGH2). The second one is to solve for pressure and enthalpy to increase the stability of phase transition between single and two-phase states (e.g. Hydrotherm). We adopted the second option. We solve the system by using a splitting method — to get rid of the complexity of coupling equations — and a finite volume method for the spatial discretization. We offer some freedom to users thanks to the implementation of several methods like explicit or implicit Euler, Runge-Kutta or BDF2 for time solvers or GMRES and BICGSTAB for the linear solver. We can handle several boundary conditions like no-flow — describing a boundary which cannot exchange matter withthe exterior — or like a mixed-therm condition — a Dirichlet condition to the pressure and a Dirichlet or an outflow condition to the temperature in order to describe a recharge or a discharge zone — …Selecting object-oriented languages, we developed a multi-language framework, combining Python, Fortran and a C++ implementation of IAPWS (from the freesteam project) including the supercritical equations. To close the system physical propertiesare determined by the IAPWS- IF97 thermodynamic formulation. We’ve applied this simulation model to the dogger in Paris, France, to several onedimensional systems and a two-dimensional one made by Coumou with the CSMP++platform. The dogger is a reservoir exploited to produce heat by pumping water at 70 _C and reinjecting it in the reservoir at 40 _C. In the one-dimensional systems we wanted to observe the process of heat transfer from a higher temperature boundary to a smaller one in a high-energy domain. The last simulation shows the natural convection of water in a fault. For every simulation we compared the solutions we found with another code (TOUGH2 or CSMP++) and they agreed
Marusic-Paloka, Eduard. "Modélisation par homogénéisation des écoulements en milieux poreux fissurés." Saint-Etienne, 1995. http://www.theses.fr/1995STET4008.
Full textMostefai, Mohamed Sadek. "Déduction rigoureuse de l'équation de Reynolds à partir d'un système modélisant l'écoulement à faible épaisseur d'un fluide micropolaire, et étude de deux problèmes à frontière libre : Hele-Shaw généralisé et Stephan à deux phases pour un fluide non newtonien." Saint-Etienne, 1997. http://www.theses.fr/1997STET4019.
Full textThibaud, Laurent. "Contribution à l'étude de la convection naturelle à l'intérieur d'un cylindre vertical poreux soumis à une densité de flux thermique parietal constante : application aux silos à grains." Poitiers, 1988. http://www.theses.fr/1988POIT2299.
Full textWelsh, WD. "Groundwater balance modelling with Darcy's Law." Phd thesis, 2007. http://hdl.handle.net/1885/48015.
Full textKarthigesu, Thayalan. "Validity of Darcy's law for low-gradient saturated flow through bentonite and sand mixtures." 1994. http://hdl.handle.net/1993/18130.
Full textDelchini, Marc Olivier. "A Preliminary Study to Assess Model Uncertainties in Fluid Flows." Thesis, 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7793.
Full textLehr, Heather Lyn Arbogast Todd J. "Analysis of a Darcy-Stokes system modeling flow through vuggy porous media." 2004. http://wwwlib.umi.com/cr/utexas/fullcit?p3143297.
Full textRath, James Michael 1975. "Multiscale basis optimization for Darcy flow." Thesis, 2007. http://hdl.handle.net/2152/3977.
Full texttext
Lehr, Heather Lyn. "Analysis of a Darcy-Stokes system modeling flow through vuggy porous media." Thesis, 2004. http://hdl.handle.net/2152/1234.
Full textSan, Martin Gomez Mario. "A three dimensional finite element method and multigrid solver for a Darcy-Stokes system and applications to vuggy porous media." Thesis, 2007. http://hdl.handle.net/2152/2929.
Full textSan, Martin Gomez Mario 1968. "A three dimensional finite element method and multigrid solver for a Darcy-Stokes system and applications to vuggy porous media." 2007. http://hdl.handle.net/2152/13131.
Full textLiu, Kun. "Discontinuous Galerkin Methods for Parabolic Partial Differential Equations with Random Input Data." Thesis, 2013. http://hdl.handle.net/1911/71989.
Full textGannavaram, Spandana. "Modeling and design optimization of a microfluidic chip for isolation of rare cells." Thesis, 2013. http://hdl.handle.net/1805/4442.
Full textCancer is still among those diseases that prominently contribute to the numerous deaths that are caused each year. But as technology and research is reaching new zeniths in the present times, cure or early detection of cancer is possible. The detection of rare cells can help understand the origin of many diseases. The current study deals with one such technology that is used for the capture or effective separation of these rare cells called Lab-on-a-chip microchip technology. The isolation and capture of rare cells is a problem uniquely suited to microfluidic devices, in which geometries on the cellular length scale can be engineered and a wide range of chemical functionalizations can be implemented. The performance of such devices is primarily affected by the chemical interaction between the cell and the capture surface and the mechanics of cell-surface collision and adhesion. This study focuses on the fundamental adhesion and transport mechanisms in rare cell-capture microdevices, and explores modern device design strategies in a transport context. The biorheology and engineering parameters of cell adhesion are defined; chip geometries are reviewed. Transport at the microscale, cell-wall interactions that result in cell motion across streamlines, is discussed. We have concentrated majorly on the fluid dynamics design of the chip. A simplified description of the device would be to say that the chip is at micro scale. There are posts arranged on the chip such that the arrangement will lead to a higher capture of rare cells. Blood consisting of rare cells will be passed through the chip and the posts will pose as an obstruction so that the interception and capture efficiency of the rare cells increases. The captured cells can be observed by fluorescence microscopy. As compared to previous studies of using solid microposts, we will be incorporating a new concept of cylindrical shell micropost. This type of micropost consists of a solid inner core and the annulus area is covered with a forest of silicon nanopillars. Utilization of such a design helps in increasing the interception and capture efficiency and reducing the hydrodynamic resistance between the cells and the posts. Computational analysis is done for different designs of the posts. Drag on the microposts due to fluid flow has a great significance on the capture efficiency of the chip. Also, the arrangement of the posts is important to contributing to the increase in the interception efficiency. The effects of these parameters on the efficiency in junction with other factors have been studied and quantified. The study is concluded by discussing design strategies with a focus on leveraging the underlying transport phenomena to maximize device performance.
Kociánová, Barbora. "Matematické modelování perfúze jater." Master's thesis, 2019. http://www.nusl.cz/ntk/nusl-406142.
Full textChaudhary, Kuldeep. "Pore-scale controls of fluid flow laws and the cappillary trapping of CO₂." 2013. http://hdl.handle.net/2152/22083.
Full texttext