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Littérature scientifique sur le sujet « Fluid fingering »

Auteur : Grafiati

Publié le 20 décembre 2023

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Articles de revues sur le sujet "Fluid fingering"

Ait Abderrahmane, Hamid, Shahid Rabbani et Mohamed Sassi. « Inertia Effects in the Dynamics of Viscous Fingering of Miscible Fluids in Porous Media : Circular Hele-Shaw Cell Configuration ». Energies 14, n^o 19 (8 octobre 2021) : 6432. http://dx.doi.org/10.3390/en14196432.

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We present a numerical study of viscous fingering occurring during the displacement of a high viscosity fluid by low viscosity fluid in a circular Hele-Shaw cell. This study assumes that the fluids are miscible and considers the effects of inertial forces on fingering morphology, mixing, and displacement efficiency. This study shows that inertia has stabilizing effects on the fingering instability and improves the displacement efficiency at a high log-mobility-viscosity ratio between displacing and displaced fluids. Under certain conditions, inertia slightly reduces the finger-split phenomenon and the mixing between the two fluids.

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Holloway, Kristi E., et John R. de Bruyn. « Viscous fingering with a single fluid ». Canadian Journal of Physics 83, n^o 5 (1 mai 2005) : 551–64. http://dx.doi.org/10.1139/p05-024.

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We study fingering that occurs when hot glycerine displaces cooler, more viscous glycerine in a radial Hele-Shaw cell. We find that fingering occurs for a sufficiently large initial viscosity contrast and for sufficiently high flow rates of the displacing fluid. The wavelength of the fingering instability is proportional to the cell width for thin cells, but the ratio of wavelength to cell width decreases for our thickest cell. Similar fingering is seen in numerical simulations of this system.PACS Nos.: 47.54.+r, 68.15.+e, 47.20.k

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Shiri, Yousef, et Alireza Shiri. « NUMERICAL INVESTIGATION OF FLUID FLOW INSTABILITIES IN PORE-SCALE WITH HETEROGENEITIES IN PERMEABILITY AND WETTABILITY ». Rudarsko-geološko-naftni zbornik 36, n^o 3 (2021) : 143–56. http://dx.doi.org/10.17794/rgn.2021.3.10.

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Quadrant geometry with permeability and wettability contrast occurs in different events, such as faults, wellbore damage, and perforation zones. In these events, understanding the dynamics of immiscible fluid displacement is vital for enhanced oil recovery. Fluid flow studies showed that viscous fingering occurs due to viscous instabilities that depend on the mobility of fluids and capillary forces. Besides, the porous domain heterogeneity is also effective on the formation of fingering. So, the purpose of the current research is to numerically investigate the effect of heterogeneity in wettability and permeability, and flow properties in Saffmann-Taylor instabilities. Numerical simulations with different flow rates in the permeability contrast model illustrated the nodal crossflow, growth of viscous fingering in the nodal part, and bypass flow in the second zone. In the wettability contrast model, a capillary fingering pattern is observed and fluid patches are isolated because of capillary force and the end effects are trapped within the quadrant. Moreover, the consequences of wettability on apparent wettability that alters the fluid-front pattern and displacement efficiency are shown.

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Li, Peisheng, Chengyu Peng, Peng Du, Ying Zhang, Boheng Dong et Ming Ma. « The investigation of the viscous fingering phenomenon of immiscible fluids displacement by the Lattice Boltzmann method ». Canadian Journal of Physics 98, n^o 7 (juillet 2020) : 650–59. http://dx.doi.org/10.1139/cjp-2019-0120.

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In this paper, the viscous fingering phenomena of two immiscible fluids with a large viscosity ratio was simulated by the Lattice Boltzmann method. The Rothman–Keller Lattice Boltzmann model was applied to study the viscous fingering phenomena in a microchannel where the high viscosity fluids were displaced by low viscosity fluids. We have investigated the influences of parameters such as viscosity ratio (M), surface wettability, capillary number (Ca), and Reynolds number (Re) on finger structures, breakthrough time (Ts), and areal sweep efficiency (Se). In particular, the effects of surface tension and large viscosity ratio on the phenomenon of fluid accumulation were intensively studied. The simulation results showed that the fluid accumulation became more obvious gradually with the increase of M, which led to more serious displacement effects. Moreover, Se increased as the contact angle increased. Besides, as the viscous fingering phenomenon weakened, the phenomenon of fluid accumulation became more evident. Furthermore, the finger pattern had a tendency to increase as the value of Ca and Re increased, and the phenomenon of fluid accumulation decreased with the decrease of Ts and Se.

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Gao, Wanxiang, Sheng Zhang, Nanxi Zhang, Xiaowu Xiong, Zhaojun Shi et Ka Sun. « Generating Fingerings for Piano Music with Model-Based Reinforcement Learning ». Applied Sciences 13, n^o 20 (15 octobre 2023) : 11321. http://dx.doi.org/10.3390/app132011321.

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The piano fingering annotation task refers to assigning finger labels to notes in piano sheet music. Good fingering helps improve the smoothness and musicality of piano performance. In this paper, we propose a method for automatically generating piano fingering using a model-based reinforcement learning algorithm. We treat fingering annotation as a partial constraint combinatorial optimization problem and establish an environment model for the piano performance process based on prior knowledge. We design a reward function based on the principle of minimal motion and use reinforcement learning algorithms to decide the optimal fingering combinations. Our innovation lies in establishing a more realistic environment model and adopting a model-based reinforcement learning approach, compared to model-free methods, to enhance the utilization of samples. We also propose a music score segmentation method to parallelize the fingering annotation task. The experimental section shows that our method achieves good results in eliminating physically impossible fingerings and reducing the amount of finger motion required in piano performance.

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Ērglis, K., A. Tatulcenkov, G. Kitenbergs, O. Petrichenko, F. G. Ergin, B. B. Watz et A. Cēbers. « Magnetic field driven micro-convection in the Hele-Shaw cell ». Journal of Fluid Mechanics 714 (2 janvier 2013) : 612–33. http://dx.doi.org/10.1017/jfm.2012.512.

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AbstractMicro-convection caused by ponderomotive forces of the self-magnetic field of a magnetic fluid in the Hele-Shaw cell under the action of a vertical homogeneous magnetic field is studied both experimentally and numerically. It is shown that a non-potential magnetic force at magnetic Rayleigh numbers greater than the critical value causes fingering at the interface between the miscible magnetic and non-magnetic fluids. The threshold value of the magnetic Rayleigh number depends on the smearing of the interface between fluids. Fingering with its subsequent decay due to diffusion of particles significantly increases the mixing at the interface. Velocity and vorticity fields at fingering are determined by particle image velocimetry measurements and qualitatively correspond well to the results of numerical simulations of the micro-convection in the Hele-Shaw cell carried out in the Darcy approximation, which account for ponderomotive forces of the self-magnetic field of the magnetic fluid. Gravity plays an important role at the initial stage of the fingering observed in the experiments.

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Suekane, Tetsuya, Tomotaka Koe et Pablo Marin Barbancho. « Three-Dimensional Interaction of Viscous Fingering and Gravitational Segregation in Porous Media ». Fluids 4, n^o 3 (12 juillet 2019) : 130. http://dx.doi.org/10.3390/fluids4030130.

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Viscous fingering is fluid dynamics instability induced on the displacement front when a less viscous fluid (LVF) displaces a more viscous fluid (MVF), thereby reducing the displacement efficiency. The displacement of a denser fluid by a less dense fluid produces a gravitational tongue. This gravitational segregation also reduces the displacement efficiency. In this study, the three-dimensional structure of the fingering pattern at the viscous fingering to gravitational segregation boundary was examined using X-ray microtomography on a packed bed of particles. At low gravity numbers, viscous fingering resembled that without gravity characterized by nonlinear interaction including tip-splitting, shielding, and coalescence. At intermediate gravity numbers, viscous fingering is associated with the gravitational tongue due to segregation. At high gravity numbers, a clear gravitational tongue penetrates from the inlet to the outlet. Consequently, the concentration near the injection point decreases and exhibits a flat profile in the flow direction. The displacement efficiency decreases with increasing gravity number, with the highest value achieved without gravity but depends on many factors, including the viscosity ratio and Péclet number.

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Mafi, MD, Zhen Qin, Yuting Wu, Sung-Ki Lyu et Chicheng Ma. « Research on the Interfacial Instability of Non-Newtonian Fluid Displacement Using Flow Geometry ». Coatings 13, n^o 11 (27 octobre 2023) : 1848. http://dx.doi.org/10.3390/coatings13111848.

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The variation of the classical viscous fingering instability is studied numerically in this work. An investigation of the viscous fingering phenomenon of immiscible displacement in the Hele–Shaw cell (HSC), where the displaced fluid is a shear-thinning fluid, was carried out numerically using the volume of fluid (VOF) method by adding a minor depth gradient or altering the geometry of the top plate in the HSC. The findings demonstrate how the presence of depth gradients can change the stability of the interface and offer a chance to regulate and adapt the fingering instability in response to the viscous fingering properties of air driving non-Newtonian fluids under various depth gradients. The relative breadth will shrink under the influence of the depth gradient, and the negative consequences of the gradient will be increasingly noticeable. Specifically, under different power-law indices, we found that with the enhancement of shear-thinning characteristics (lower power-law exponent n) in both positive and negative depth gradients, the fingers that protrude from the viscous fingers become shorter and thicker, resulting in higher displacement efficiency. Additionally, several modifications were performed to the upper plate’s design, and the findings revealed that the shape had no effect on the viscous fingering and only had an impact on the longitudinal amplitude. Based on the aforementioned traits, we may alter the HSC’s form or depth gradient to provide high-quality and effective work.

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Kessler, David A., et Herbert Levine. « Microscopic Selection of Fluid Fingering Patterns ». Physical Review Letters 86, n^o 20 (14 mai 2001) : 4532–35. http://dx.doi.org/10.1103/physrevlett.86.4532.

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Alsac, E., C. Laroche, E. Lemaire et H. Van Damme. « Viscochemical fingering in a colloidal fluid ». Chemical Physics Letters 165, n^o 4 (janvier 1990) : 277–82. http://dx.doi.org/10.1016/0009-2614(90)87188-w.

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Thèses sur le sujet "Fluid fingering"

Beeson-Jones, Timothy. « Controlling viscous fingering ». Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/275358.

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Viscous fingering occurs when one fluid displaces another fluid of a greater viscosity in a porous medium or a Hele-Shaw cell. Linear stability analysis is used to predict methods of suppressing instability. Then, experiments in which nonlinear growth dominates pattern formation are analysed to explore the nonlinear impact of strategies of suppressing finger growth. Often, chemical treatment fluid is injected into oil reservoirs in order to prevent sand production. This treatment fluid is usually followed by water injection to clean up the well. We explore the potential for viscous instability of the interface between the treatment fluid and the water, and also the treatment fluid and the oil, as a function of the volume of treatment fluid and the injection rate and viscosity ratios of the different fluids. For a given volume of treatment fluid and a given injection rate, we find the optimal viscosity of the treatment fluid to minimise the viscous instability. In the case of axisymmetric injection, the stabilisation associated with the azimuthal stretching of modes leads to a further constraint on the optimisation of the viscosity. In the case of oil production, polymers may be added to the displacing water in order to reduce adverse viscosity gradients. We also explore the case in which these polymers have a time-dependent viscosity, for example through the slow release from encapsulant. We calculate the injection flow rate profile that minimises the final amplitude of instability in both rectilinear and axisymmetric geometries. In a development of the model, we repeat the calculation for a shear-thinning rheology. Finally, experiments are analysed in which the nonlinear growth of viscous fingers develops to test the influence of different injection profiles on the development of instability. Diffusion Limited Aggregation (DLA) simulations are performed for comparison. In all cases, the evolving pattern has a saturation distribution, with an inner zone in which the fingers are static and an outer zone in which the fingers advance and grow. In the very centre of the viscous fingering patterns, there is a small fully-saturated region. In the experiments, the mass distribution in the inner zone varies with radius as a power law which relates to the fractal dimension for the analogue DLA simulations. In the outer region the saturation decreases linearly with radius. The radius of the inner frozen zone is approximately 2/3 of the outer radius in the cases of DLA and -- after a period of evolution -- the viscous fingering experiments. This allows the radial extents of the inner and outer zones to be predicted. The ratio of each radius to the extent of the fully-saturated region is independent of the injection profile and corresponds to values for DLA.

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Rees, S. « Stochastic computer simulations of viscous fingering ». Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235262.

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This thesis aims to develop a computer simulation of the process that occurs when one displaces a viscous fluid such as oil by a less viscous one such as water in a porous medium. Chapter 1 outlines the problem and explains why a computer simulation rather than analytical treatment is necessary for the problem. Previous computer simulations of the problem are reviewed and their respective advantages and disadvantages are considered. Chapter 2 introduces the concept of 'simulated annealing', a stochastic computational technique for solving minimisation problems with many variables and this technique is used to make a crude model of the displacement problem. The results from this are considered and the reasons for the model's failure to adequately solve the problem are discussed. In chapter 3, simulated annealing is applied to the simpler problem of the travelling salesman where one has to find the shortest route around a collection of points. The aim of this chapter is to try and find an optimum simulated annealing schedule to minimise the computer time needed to achieve a satisfactory solution. This is successfully accomplished for this particular problem by fitting the relaxation time of the system as a function of temperature to an Arrhenhius type law. But this optimisation is problem specific and it is concluded that the complicated nature of the oil displacement problem effectively precludes treatment by annealing. In chapter 4 a stochastic micro model is developed in which a pressure gradient across the system forces water into oil bearing pores. The pores have varying sizes which represent sizes which represent the varying permeability in a porous medium. A modified Gauss Seidel method is used to solve for the pressure field and an analytic expression for the saturation update is developed. The final chapter, chapter 5, develops the above model further and in particular develops a scheme whereby conservation of fluid is guaranteed. The profiles of the fingering of the water into the oil are studied and it is found that their interface fractal dimension varies monotonically with viscosity ratio.

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Chen, Falin. « Thermal and fingering convection in superposed fluid and porous layers ». Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184774.

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Thermal and fingering convection in a horizontal porous layer underlying a fluid layer was studied using linear stability analysis, experiment (for the thermal convection case only), and nonlinear simulation. For the thermal convection case, the linear analysis shows that when the fluid layer is thin, convection is largely confined to the porous layer. When the fluid layer thickness exceeds 15% of the porous layer thickness, convection is localized in the fluid layer and the critical wavelength is dramatically reduced. Experimental investigations were then conducted in a test box 24 cm x 12 cm x 4 cm high to substantiate the predictions. The ratio of the thickness of the fluid layer to that of the porous layer, d, varied from 0 to 1. The results were in good agreement with predictions. To investigate supercritical convection, a nonlinear computational study was carried out. It was found that for d ≤ 0.13, the Nusselt number increases sharply with the thermal Rayleigh number, whereas at larger values of d, the increase is more moderate. Heat transfer rates predicted for d = 0.1 and 0.2 are in good agreement with the experimental results. For salt-finger convection at R(m) ≤ 1, the critical value of the solute Rayleigh number R(sm) decreases as d increases; the convection is unicellular. For 5 ≤ R(m) ≤ 10, the critical R(sm) initially decreases with d, and then remains almost constant for larger values of d; multicellular convection prevails at high d. For 20 ≤ R(m) ≤ 50, the critical R(sm) first decreases and then increases as d increases from 0 to 0.1. When d > 0.1, the critical R(sm) decreases slowly with d and remains almost constant for d ≥ 0.4. In the nonlinear computations for R(m) = 1, periodic convection sets in at a value of R(sm) between ten and eleven times the critical value. For the case of R(m) = 50, an aperiodic oscillation occurs when R(sm) is between four and five times the critical value. For the superposed layer cases d = 1 and 0.5, the convection characteristics are similar to those of thermal convection when R(m) = 0.01. For R(m) = 1, it was found that the onset of salt-finger convection is oscillatory. For R(m) = 50, the nonlinear code failed to obtain satisfactory results.

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Zhang, Hao-Ran. « Numerical modelling of viscous fingering and upscaling of fluid flow porcesses in porous media ». Thesis, Heriot-Watt University, 1994. http://hdl.handle.net/10399/1352.

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Jackson, Samuel J. « A numerical study on the viscous fingering instability of immiscible displacement in Hele-Shaw cells ». Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/40716/.

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In this thesis, the viscous fingering instability of radial immiscible displacement is analysed numerically using novel mesh-reduction and interface tracking techniques. Using a reduced Hele-Shaw model for the depth averaged lateral flow, viscous fingering instabilities are explored in flow regimes typical of subsurface carbon sequestration involving supercritical CO2 - brine displacements, i.e. with high capillary numbers, low mobility ratios and inhomogeneous permeability/temperature fields. A high accuracy boundary element method (BEM) is implemented for the solution of homogeneous, finite mobility ratio immiscible displacements. Through efficient, explicit tracking of the sharp fluid-fluid interface, classical fingering processes such as spreading, shielding and splitting are analysed in the late stages of finger growth at low mobility ratios and high capillary numbers. Under these conditions, large differences are found compared with previous high or infinite mobility ratio models and critical events such as plume break-off and coalescence are analysed in much greater detail than has previously been attempted. For the solution of inhomogeneous mobility problems, a novel meshless radial basis function-finite collocation method is developed that utilises a dynamic quadtree dataset and local enforcement of interface matching conditions. When coupled with the BEM, the numerical scheme allows the analysis of variable permeability effects and the transition in (de)stabilising mechanisms that occurs when the capillary number is increased with a fixed, spatially varying permeability. Finally, thermo-viscous fingering is explored in the context of immiscible flows, with a detailed mechanistic study presented to explain, for the first time, the immiscible thermo-viscous fingering process.

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Matioc, Bogdan-Vasile [Verfasser]. « Viscous Fingering in Mathematical Fluid Dynamics via Bifurcation : A Functional Analytic Approach / Bogdan-Vasile Matioc ». Saarbrücken : Suedwestdeutscher Verlag fuer Hochschulschriften, 2010. http://www.vdm-verlag.de.

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Zhang, Fengshou. « Pattern formation in fluid injection into dense granular media ». Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43716.

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Integrated theoretical and experimental analysis is carried out in this work to investigate the fundamental failure mechanisms and flow patterns involved in the process of fluid injection into dense granular media. The experimental work is conducted with aqueous glycerin solutions, utilizing a novel setup based on a Hele-Shaw cell filled with dense dry sand. The two dimensional nature of the setup allows direct visualization and imaging analysis of the real-time fluid and grain kinematics. The experimental results reveal that the fluid flow patterns show a transition from simple radial flow to a ramified morphology while the granular media behaviors change from that of rigid porous media to localized failure that lead to development of fluid channels. Based on the failure/flow patterns, four distinct failure/flow regimes can be identified, namely, (i) a simple radial flow regime, (ii) an infiltration-dominated regime, (iii) a grain displacement-dominated regime, and (iv) a viscous fingering-dominated regime. These distinct failure/flow regimes emerge as a result of competition among various energy dissipation mechanisms, namely, viscous dissipation through infiltration, dissipation due to grain displacements, and viscous dissipation through flow in thin channels and can be classified based on the characteristic times associated with fluid injection, hydromechanical coupling and viscoelastoplasticity. The injection process is also analyzed numerically using the discrete element method (DEM) coupled with two fluid flow scheme, a fixed coarse grid scheme based on computational fluid dynamics (CFD) and a pore network modeling scheme. The numerical results from the two complementary methods reproduce phenomena consistent with the experimental observations and justify the concept of associating the displacement regimes with the partition among energy dissipation mechanisms. The research in this work, though fundamental in nature, will have direct impacts on many engineering problems in civil, environmental and petroleum engineering such as ground improvement, environmental remediation and reservoir stimulation.

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D'Hernoncourt, Jessica. « Influence of thermal effects and electric fields on fingering of chemical fronts : a theoretical study ». Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210607.

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Several types of instability can affect the interface between two fluids. For instance, a Rayleigh-Taylor instability (or density fingering) is encountered when a heavier fluid is placed upon a lighter one in the gravity field and double diffusive instabilities can be triggered by differential diffusivity of the different species present in the fluid.

In this context our work aims to understand theoretically in which way a chemical reaction can induce and influence such instabilities in a fluid initially at rest.

To understand the dynamics resulting from the coupling between chemical reactions and hydrodynamical instabilities we use chemical fronts as model systems. These fronts result from the coupling between autocatalytical chemical reactions and diffusion and they allow to create a self-organized interface between the products and the reactants. As during a chemical reaction the density may vary due to solutal and thermal effects, the products and the reactants can have different densities which may trigger convection movements leading to the destabilization of the fronts.

We have in particular studied the influence of the exothermicity of the reaction on the fingering of chemical fronts, focusing first on the influence of heat losses through the walls of the set-up.

These leaks have a marked influence on the dynamics because they affect the temperature profiles and hence the density profiles too. We have also classified the various types of instabilities that may appear dues to solutal and thermal effects. We have found a new type of hydrodynamic instability of statically stable fronts induced by the chemical reaction.

We have furthermore analyzed an isothermal model with two chemical species. If they diffuse at different rates the front can be subject to diffusive instabilities as well. We have shown that the coupling between such a diffusive instability and fingering can trigger complex dynamics. We have eventually studied the influence of an external electric field on the diffusive instabilities and on fingering underlying the possibility to destabilize otherwise stable fronts./

Différents types d'instabilités hydrodynamiques peuvent affecter les interfaces entre deux fluides comme par exemple, une instabilité de Rayleigh-Taylor (ou digitation de densité) quand un fluide plus dense se trouve placé au-dessus d'un fluide moins dense dans le champ de gravité ou des instabilités de double diffusion induites par des différences entre les diffusivités d'un soluté et de la chaleur contenus dans les fluides. Dans ce contexte, notre thèse s'attache à comprendre de manière théorique comment une réaction chimique peut influencer ces instabilités voire les générer dans un fluide initialement au repos. Pour étudier les dynamiques résultant du couplage entre réactions chimiques et instabilités hydrodynamiques, nous utilisons des systèmes modèles: les fronts chimiques de conversion résultant de la compétition entre réactions chimiques autocatalytiques et diffusion créant une interface auto-organisée entre les réactifs et les produits. Comme au cours d'une réaction chimique la densité peut varier par des effets solutaux et thermiques, les produits et les réactifs de densités différentes peuvent générer des mouvements de convection qui conduisent à la déstabilisation des fronts.

Nous avons en particulier étudié l'influence de l'exothermicité de la réaction sur les instabilités de digitation de fronts chimiques, en nous focalisant dans un premier temps sur l'influence des pertes de chaleur par les parois du réacteur.

Ces fuites ont un effet marqué sur les instabilitités car elles affectent les profils de température et donc les profils de densité dans le système. Nous avons également classifié les différentes instabilités qui peuvent apparaître via des changements de densité dûs à des effets thermiques et solutaux et mis en évidence un nouveau type de déstabilisation hydrodynamique de fronts statiquement stables induit par une réaction chimique.

Nous avons ensuite analysé un modèle isotherme impliquant deux espèces chimiques. Si ces dernières diffusent a des vitesses différentes le front peut être sujet à une instabilité diffusive. Nous avons montré qu'un couplage entre une telle instabilité diffusive et de la digitation peut être à l'origine de dynamiques complexes. Nous avons ensuite considéré l'influence d'un champ électrique sur les instabilité diffusives et de digitation en soulignant la possibilié de déstabiliser via ce champ des fronts initialement stables.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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Booth, Richard J. S. « Miscible flow through porous media ». Thesis, University of Oxford, 2008. http://ora.ox.ac.uk/objects/uuid:542d3ec1-2894-4a34-9b93-94bc639720c9.

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This thesis is concerned with the modelling of miscible fluid flow through porous media, with the intended application being the displacement of oil from a reservoir by a solvent with which the oil is miscible. The primary difficulty that we encounter with such modelling is the existence of a fingering instability that arises from the viscosity and the density differences between the oil and solvent. We take as our basic model the Peaceman model, which we derive from first principles as the combination of Darcy’s law with the mass transport of solvent by advection and hydrodynamic dispersion. In the oil industry, advection is usually dominant, so that the Péclet number, Pe, is large. We begin by neglecting the effect of density differences between the two fluids and concentrate only on the viscous fingering instability. A stability analysis and numerical simulations are used to show that the wavelength of the instability is proportional to Pe^−1/2, and hence that a large number of fingers will be formed. We next apply homogenisation theory to investigate the evolution of the average concentration of solvent when the mean flow is one-dimensional, and discuss the rationale behind the Koval model. We then attempt to explain why the mixing zone in which fingering is present grows at the observed rate, which is different from that predicted by a naive version of the Koval model. We associate the shocks that appear in our homogenised model with the tips and roots of the fingers, the tip-regions being modelled by Saffman-Taylor finger solutions. We then extend our model to consider flow through porous media that are heterogeneous at the macroscopic scale, and where the mean flow is not one dimensional. We compare our model with that of Todd & Longstaff and also models for immiscible flow through porous media. Finally, we extend our work to consider miscible displacements in which both density and viscosity differences between the two fluids are relevant.

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Vienne, Lucien. « Simulation of multi-component flows by the lattice Boltzmann method and application to the viscous fingering instability ». Thesis, Paris, CNAM, 2019. http://www.theses.fr/2019CNAM1257/document.

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La méthode de Boltzmann sur réseau est une formulation discrète particulière de l'équation de Boltzmann. Depuis ses débuts, il y a trente ans, cette méthode a gagné une certaine popularité, et elle est maintenant utilisée dans presque tous les problèmes habituellement rencontrés en mécanique des fluides notamment pour les écoulements multi-espèces. Dans le cadre de ce travail, une force de friction intermoléculaire est introduite pour modéliser les interactions entre les molécules de différent types causant principalement la diffusion entre les espèces. Les phénomènes de dissipation visqueuse (collision usuelle) et de diffusion moléculaire (force de friction intermoléculaire) sont séparés et peuvent être ajuster indépendamment. Le principal avantage de cette stratégie est sa compatibilité avec des optimisations de la collision usuelle et les opérateurs de collision avancés. Adapter un code mono-espèce pour aboutir à un code multi-espèces est aisé et demande beaucoup moins d’effort comparé aux précédentes tentatives. De plus, il n’ y a pas d’approximation du mélange, chaque espèce a ses propres coefficients de transport pouvant être calculés à l’aide de la théorie cinétique des gaz. En général, la diffusion et la convection sont vus comme deux mécanismes séparés : l’un agissant sur la masse d’une espèce, l’autre sur la quantité de mouvement du mélange. En utilisant une force de friction intermoléculaire, la diffusion et la convection sont couplés par l’intermédiaire la quantité de mouvement de chaque espèce. Les mécanismes de diffusion et de convection sont intimement liés dans de nombreux phénomènes physique tel que la digitation visqueuse.L’instabilité de digitation visqueuse est simulée en considérant dans un milieu poreux deux espèces dans des proportions différentes soit un mélange moins visqueux déplaçant un mélange plus visqueux. Les principaux moteurs de l’instabilité sont la diffusion et le contraste de viscosité entre les espèces. Deux stratégies sont envisagées pour simuler les effets d’un milieu poreux. Les méthodes de rebond partiel et de force de Brinkman bien que basées sur des approches fondamentalement différentes donnent dans notre cas des résultats identiques. Les taux de croissance de l’instabilité calculés à partir de la simulation coïncident avec ceux obtenus à partir d’analyses de stabilité linéaire. L’évolution de la longueur de mélange peut être divisée en deux étapes dominées d’abord par la diffusion puis par la convection. La physique de la digitation visqueuse est ainsi correctement simulée. Toutefois, les effets de diffusion multi-espèces ne sont généralement pas pris en compte lors de la digitation visqueuse de trois espèces et plus. Ces derniers ne sont pas négligeable puisque nous mettons en avant une configuration initialement stable qui se déstabilise. La diffusion inverse entraîne la digitation dont l’impact dépend de la diffusion entre les espèces
The lattice Boltzmann method (LBM) is a specific discrete formulation of the Boltzmann equation. Since its first premises, thirty years ago, this method has gained some popularity and is now applied to almost all standard problems encountered in fluid mechanics including multi-component flows. In this work, we introduce the inter-molecular friction forces to take into account the interaction between molecules of different kinds resulting primarily in diffusion between components. Viscous dissipation (standard collision) and molecular diffusion (inter-molecular friction forces) phenomena are split, and both can be tuned distinctively. The main advantage of this strategy is optimizations of the collision and advanced collision operators are readily compatible. Adapting an existing code from single component to multiple miscible components is straightforward and required much less effort than the large modifications needed from previously available lattice Boltzmann models. Besides, there is no mixture approximation: each species has its own transport coefficients, which can be calculated from the kinetic theory of gases. In general, diffusion and convection are dealt with two separate mechanisms: one acting respectively on the species mass and the other acting on the mixture momentum. By employing an inter-molecular friction force, the diffusion and convection are coupled through the species momentum. Diffusion and convection mechanisms are closely related in several physical phenomena such as in the viscous fingering instability.A simulation of the viscous fingering instability is achieved by considering two species in different proportions in a porous medium: a less viscous mixture displacing a more viscous mixture. The core ingredients of the instability are the diffusion and the viscosity contrast between the components. Two strategies are investigated to mimic the effects of the porous medium. The gray lattice Boltzmann and Brinkman force models, although based on fundamentally different approaches, give in our case equivalent results. For early times, comparisons with linear stability analyses agree well with the growth rate calculated from the simulations. For intermediate times, the evolution of the mixing length can be divided into two stages dominated first by diffusion then by convection, as found in the literature. The whole physics of the viscous fingering is thus accurately simulated. Nevertheless, multi-component diffusion effects are usually not taken into account in the case of viscous fingering with three and more species. These effects are non-negligible as we showcase an initial stable configuration that becomes unstable. The reverse diffusion induces fingering whose impact depends on the diffusion between species

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Livres sur le sujet "Fluid fingering"

M, Taniguchi, Neuman S. P, University of Arizona. Dept. of Hydrology and Water Resources. et U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Regulatory Applications., dir. An overview of instability and fingering during immiscible fluid flow in porous and fractured media. Washington, DC : Division of Regulatory Applications, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1995.

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G, Chen. An overview of instability and fingering during immiscible fluid flow in porous and fractured media. Washington, DC : Division of Regulatory Applications, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1995.

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Interfacial wave theory of pattern formation : Selection of dendritic growth and viscous fingering in Hele-Shaw flow. Berlin : Springer, 1998.

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Chapitres de livres sur le sujet "Fluid fingering"

Chen, Ching-Yao, Shu-Wei Wang et Yu-Chia Liu. « Fingering Instabilities in a Miscible Rotating Hele-Shaw Flow ». Dans Computational Fluid Dynamics 2002, 473–78. Berlin, Heidelberg : Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-59334-5_70.

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Choksi, Bhumika G., Twinkle R. Singh et Rajiv K. Singh. « An Approximate Solution of Fingering Phenomenon Arising in Porous Media by Successive Linearisation Method ». Dans Numerical Heat Transfer and Fluid Flow, 1–8. Singapore : Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-1903-7_1.

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Tani, Atusi, et Hisasi Tani. « Classical Solvability of the Two-Phase Radial Viscous Fingering Problem in a Hele-Shaw Cell ». Dans Mathematical Fluid Dynamics, Present and Future, 317–48. Tokyo : Springer Japan, 2016. http://dx.doi.org/10.1007/978-4-431-56457-7_11.

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Riolfo, L. A., Y. Nagatsu, P. M. J. Trevelyan et A. De Wit. « Chemically-Driven Miscible Viscous Fingering : How Can a Reaction Destabilize Typically Stable Fluid Displacements ? » Dans Proceedings of the European Conference on Complex Systems 2012, 9–13. Cham : Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-00395-5_2.

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Kawaguchi, Masami. « Viscous Fingering of Silica Suspensions Dispersed in Polymer Fluids ». Dans Nonlinear Dynamics in Polymeric Systems, 250–61. Washington, DC : American Chemical Society, 2003. http://dx.doi.org/10.1021/bk-2004-0869.ch020.

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Allen, E., et D. V. Boger. « Viscous Fingering of Non-Newtonian Fluids in Porous Media ». Dans Third European Rheology Conference and Golden Jubilee Meeting of the British Society of Rheology, 537–39. Dordrecht : Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0781-2_182.

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Couder, Y., M. Rabaud et N. Gérard. « ANOMALOUS SAFFMANN TAYLOR FINGERING ». Dans Frontiers of Fluid Mechanics, 1235–40. Elsevier, 1988. http://dx.doi.org/10.1016/b978-0-08-036232-8.50217-6.

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Lauga, Eric. « 7. Instabilities ». Dans Fluid Mechanics : A Very Short Introduction, 107–28. Oxford University Press, 2022. http://dx.doi.org/10.1093/actrade/9780198831006.003.0007.

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‘Instabilities’ addresses the physical ideas behind fundamental instability mechanisms in fluid mechanics by looking at the Rayleigh–Taylor, or gravitational, instability. This arises whenever a heavy fluid is located above a lighter one (or whenever a heavy fluid is accelerated in the direction of a lighter one). This instability is due to a net release of gravitational potential energy, which therefore encourages flow. Stability theory shows where a steady base flow is perturbed and we can derive the conditions for the perturbations to grow in time using a modal analysis along Fourier modes, with an emphasis on the relationship between the wavenumber of the perturbation and its growth rate. The Rayleigh–Plateau, or capillary, instability, can be illustrated with dripping taps, dew on plants, and spider webs. The physical origin of this instability is the release of surface energy for elongated fluid threads, leading to their tendency to pinch off in drops. The Taylor–Couette, or centrifugal instability, happens where fluids in rotation can become unstable, a consequence of the conservation of angular momentum for flows (or, alternatively, due to a release of kinetic energy), ultimately leading to Taylor vortices. The Saffman–Taylor, or fingering, instability occurs when a less viscous fluid displaces a more viscous one. This instability has important consequences in oil recovery. The Kelvin–Helmholtz instability arises in shear layers, i.e. when two flows of different magnitude merge.

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GOPINATH, ASHOK. « SEPARATION MECHANICS OF THIN INTERFACIAL LIQUID LAYERS : THE ROLE OF VISCOUS FINGERING ». Dans Interfaces for the 21st Century : New Research Directions in Fluid Mechanics and Materials Science, 258. PUBLISHED BY IMPERIAL COLLEGE PRESS AND DISTRIBUTED BY WORLD SCIENTIFIC PUBLISHING CO., 2002. http://dx.doi.org/10.1142/9781860949609_0040.

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Wang, Yulin, et Haokai Xu. « Microstructure Reconstruction and Gas-Liquid Two-Phase Transport Mechanism within Porous Electrodes of PEM Fuel Cells ». Dans Transport Perspectives for Porous Medium Applications [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.1003240.

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The structure of porous media is composed of skeleton particles and pores. Its micro-pores and solid skeleton characteristics lead to the capillary fingering movement of fluid in its porous media driven by capillary pressure. Currently, the methods of constructing porous media are mainly random construction and multi-scale imaging construction. The porous structure constructed by these two methods can show the real microstructure characteristics. The research on multiphase flow in microporous structure mainly includes VOF, MC, LBM, and other methods. In this chapter, taking the classic porous structure of polymer electrolyte membrane (PEM) fuel cell gas diffusion layer (GDL) as an example, GDL porous microstructure is constructed through random algorithm, and multiphase LBM is used to study two-phase flow in porous media to explore the relationship between porous structure characteristics and multiphase flow transport.

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Actes de conférences sur le sujet "Fluid fingering"

Chou, Chi-Chian, Yuka Deki, Ryuta Suzuki, Yuichiro Nagatsu et Ching-Yao Chen. « Poster : Fireworks of Viscous Fingering ». Dans 76th Annual Meeting of the APS Division of Fluid Dynamics. American Physical Society, 2023. http://dx.doi.org/10.1103/aps.dfd.2023.gfm.p0018.

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Ono, Shunichi, Yuichiro Nagatsu et Ryuta Suzuki. « Video : Inside of miscible viscous fingering ». Dans 75th Annual Meeting of the APS Division of Fluid Dynamics. American Physical Society, 2022. http://dx.doi.org/10.1103/aps.dfd.2022.gfm.v0093.

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WANG, L., J. CHEN et C. CHEN. « Fingering flow patterns of thermosolutal convection in rectangular enclosures ». Dans 1st National Fluid Dynamics Conference. Reston, Virigina : American Institute of Aeronautics and Astronautics, 1988. http://dx.doi.org/10.2514/6.1988-3823.

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Tsuzuki, Reiko, Yuichiro Nagatsu, Qian Li et Ching-Yao Chen. « Poster : Tearing Surfactants in Reactive Viscous Fingering ». Dans 70th Annual Meeting of the APS Division of Fluid Dynamics. American Physical Society, 2017. http://dx.doi.org/10.1103/aps.dfd.2017.gfm.p0014.

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Camassa, Roberto, Lingyun Ding, Grace McLaughlin et Richard McLaughlin. « Video : Fast Fractal Fingering in Fructose Fluids ». Dans 74th Annual Meeting of the APS Division of Fluid Dynamics. American Physical Society, 2021. http://dx.doi.org/10.1103/aps.dfd.2021.gfm.v0062.

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Medici, Ezequiel, et Jeffrey Allen. « 2D Parametric Study of Viscous Fingering ». Dans ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42024.

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When a low viscosity fluid is forced to displace another immiscible fluid with a higher viscosity inside of a porous media a particular flow structure called viscous fingering is generated. The study of that particular flow structure has special relevance in understanding the diffusion process and the transport characteristics of a fluid inside of a porous media. This work examined the effect of two fundamental parameters like the injected volumetric flow rate and the domain aspect ratio over the viscous fingering pattern. In order to perform that parametric study, a set of numerical simulations using the 2D network simulator model are used. A large viscosity ratio between the injected and displaced fluid is used to focus the work only on the unstable behavior state.

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Hillaire, Keith, Michael Dickey et Karen Daniels. « Video : Marangoni Fingering Instabilities in Oxidizing Eutectic Gallium Indium ». Dans 72th Annual Meeting of the APS Division of Fluid Dynamics. American Physical Society, 2019. http://dx.doi.org/10.1103/aps.dfd.2019.gfm.v0068.

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Tursynkhan, Margulan, Bagdagul Dauyeshova, Desmond Adair, Ernesto Monaco et Luis Rojas-Solórzano. « Simulation of Viscous Fingering in Microchannels With Hybrid-Patterned Surface Using Lattice Boltzmann Method ». Dans ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-10876.

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Abstract In recent years, a large effort has been devoted to the study of the viscous fingering phenomenon in microchannel flows. This phenomenon plays a crucial role in many fields of industry and occurs in geological sequestration of carbon dioxide (CO2), in the secondary and tertiary oil recovery stages. Viscous fingering, also known as the Saffman-Taylor instability, occurs at the unstable interface between two fluids when the less viscous fluid displaces the more viscous fluid which is originally residing in a porous medium. This paper studies viscous fingering occurring between two segregated immiscible fluids, such that the less viscous one is forced into a microchannel where the more viscous fluid initially resides. The 2D microchannel walls are present with a hybrid-patterned configuration such that the top wall is smooth, and the bottom wall is ribbed. The multiphase Shan-Chen Lattice Boltzmann Method (SC LBM) is implemented to capture the complex interfacial phenomenon since this method has proven to accurately describe multiphase interfacial entangling. The LBM is based on the discretization of micro- and mesoscopic kinetic equations and the SC LBM simulation allows us to study the viscous fingering phenomenon in terms of non-dimensional quantities, including capillary number and viscosity ratio. The effect of hybrid-patterned rough walls on fingering formation in a 2D microchannel is investigated and compared to the phenomenon when plain smooth walls are in place. The numerical results show that the SC Lattice Boltzmann multicomponent model provides insightful characteristics associated to the physical nature of the fingering phenomenon in microchannels and the role of adjacent walls.

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Suzuki, Ryuta, Manoranjan Mishra, Takahiko Ban et Yuichiro Nagatsu. « Video : Numerous droplets formation in a simple viscous fingering experiment ». Dans 69th Annual Meeting of the APS Division of Fluid Dynamics. American Physical Society, 2016. http://dx.doi.org/10.1103/aps.dfd.2016.gfm.v0113.

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Zargartalebi, Mohammad, et Jalel Azaiez. « Nanoflow Miscible Viscous Fingering in Real Porous Media : A Mesoscopic Approach ». Dans International Conference of Fluid Flow, Heat and Mass Transfer. Avestia Publishing, 2017. http://dx.doi.org/10.11159/ffhmt17.163.

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Rapports d'organisations sur le sujet "Fluid fingering"

Chen, G., S. P. Neuman et M. Taniguchi. An overview of instability and fingering during immiscible fluid flow in porous and fractured media. Office of Scientific and Technical Information (OSTI), avril 1995. http://dx.doi.org/10.2172/93758.

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