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A. De Wit - One of the best experts on this subject based on the ideXlab platform.
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Viscous Fingering Induced by a pH-Sensitive Clock Reaction.
Langmuir : the ACS journal of surfaces and colloids, 2019Co-Authors: D. M. Escala, A. De Wit, J. Carballido-landeira, Alberto P. MuñuzuriAbstract:A pH-changing clock chemical system, also known to induce changes in viscosity, is shown experimentally to induce a Viscous Fingering instability during the displacement of reactive solutions in a Hele-Shaw cell. Specifically, a low-viscosity solution of formaldehyde is displaced by a more Viscous solution of sulfite and of a pH-sensitive poly(acrylic acid) polymer. The pH change triggered by the formaldehyde–sulfite clock reaction in the reactive contact zone between the two solutions affects the polymer and induces a local increase of the viscosity that destabilizes the displacement via a Viscous Fingering instability. The influence of changes in the chemical parameters on this Fingering instability is analyzed using different techniques and the results are compared with numerical simulations.
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Reaction-driven oscillating Viscous Fingering.
Chaos (Woodbury N.Y.), 2019Co-Authors: Chinar Rana, A. De WitAbstract:Localized oscillations can develop thanks to the interplay of reaction and diffusion processes when two reactants A and B of an oscillating reaction are placed in contact, meet by diffusion, and react. We study numerically the properties of such an A+B→ oscillator configuration using the Brusselator model. The influence of a hydrodynamic Viscous Fingering instability on localized concentration oscillations is next analyzed when the oscillating chemical reaction changes the viscosity of the solutions involved. Nonlinear simulations of the related reaction-diffusion-convection equations with the fluid viscosity varying with the concentration of an intermediate oscillatory species show an active coupling between the oscillatory kinetics and the Viscously driven instability. The periodic oscillations in the concentration of the intermediate species induce localized changes in the viscosity, which in turn can affect the Fingering instability. We show that the oscillating kinetics can also trigger Viscous Fingering in an initially Viscously stable displacement, while localized changes in the viscosity profile can induce oscillations in an initially nonoscillating reactive system.
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Viscous Fingering Induced by a pH-Sensitive Clock Reaction
2019Co-Authors: D. M. Escala, A. De Wit, J. Carballido-landeira, A. P. MuñuzuriAbstract:A pH-changing clock chemical system, also known to induce changes in viscosity, is shown experimentally to induce a Viscous Fingering instability during the displacement of reactive solutions in a Hele-Shaw cell. Specifically, a low-viscosity solution of formaldehyde is displaced by a more Viscous solution of sulfite and of a pH-sensitive poly(acrylic acid) polymer. The pH change triggered by the formaldehyde–sulfite clock reaction in the reactive contact zone between the two solutions affects the polymer and induces a local increase of the viscosity that destabilizes the displacement via a Viscous Fingering instability. The influence of changes in the chemical parameters on this Fingering instability is analyzed using different techniques and the results are compared with numerical simulations
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Experimental evidence of reaction-driven miscible Viscous Fingering.
Physical Review E, 2012Co-Authors: L. A. Riolfo, Yuichiro Nagatsu, Shohei Iwata, Renaud David Maes, Philip M. J. Trevelyan, A. De WitAbstract:An experimental demonstration of reaction-driven Viscous Fingering developing when a more Viscous solution of a reactant A displaces a less Viscous miscible solution of another reactant B is presented. In the absence of reaction, such a displacement of one fluid by another less mobile one is classically stable. However, a simple A+B→C reaction can destabilize this interface if the product C is either more or less Viscous than both reactant solutions. Using the pH dependence of the viscosity of some polymer solutions, we provide experimental evidence of both scenarios. We demonstrate quantitatively that reactive Viscous Fingering results from the buildup in time of nonmonotonic viscosity profiles with patterns behind or ahead of the reaction zone, depending on whether the product is more or less Viscous than the reactants. The experimental findings are backed up by numerical simulations.
Howard A. Stone - One of the best experts on this subject based on the ideXlab platform.
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Suppressing Viscous Fingering in structured porous media
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Harris Sajjad Rabbani, Howard A. Stone, Ying Liu, Ching-yao Lai, Sujit S. Datta, Nima ShokriAbstract:Finger-like protrusions that form along fluid−fluid displacement fronts in porous media are often excited by hydrodynamic instability when low-viscosity fluids displace high-viscosity resident fluids. Such interfacial instabilities are undesirable in many natural and engineered displacement processes. We report a phenomenon whereby gradual and monotonic variation of pore sizes along the front path suppresses Viscous Fingering during immiscible displacement, that seemingly contradicts conventional expectation of enhanced instability with pore size variability. Experiments and pore-scale numerical simulations were combined with an analytical model for the characteristics of displacement front morphology as a function of the pore size gradient. Our results suggest that the gradual reduction of pore sizes act to restrain Viscous Fingering for a predictable range of flow conditions (as anticipated by gradient percolation theory). The study provides insights into ways for suppressing unwanted interfacial instabilities in porous media, and provides design principles for new engineered porous media such as exchange columns, fabric, paper, and membranes with respect to their desired immiscible displacement behavior.
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Controlling Viscous Fingering Using Time-Dependent Strategies
Physical review letters, 2015Co-Authors: Zhong Zheng, Hyoungsoo Kim, Howard A. StoneAbstract:Control and stabilization of Viscous Fingering of immiscible fluids impacts a wide variety of pressure-driven multiphase flows. We report theoretical and experimental results on a time-dependent control strategy by manipulating the gap thickness b(t) in a lifting Hele-Shaw cell in the power-law form b(t)=b(1)t(1/7). Experimental results show good quantitative agreement with the predictions of linear stability analysis. By choosing the value of a single time-independent control parameter, we can either totally suppress the Viscous Fingering instability or maintain a series of nonsplitting Viscous fingers during the fluid displacement process. In addition to the gap thickness of a Hele-Shaw cell, time-dependent control strategies can, in principle, also be placed on the injection rate, viscosity of the displaced fluid, and interfacial tension between the two fluids.
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Controlling Viscous Fingering in tapered Hele-Shaw cells
Physics of Fluids, 2013Co-Authors: Talal T. Al-housseiny, Howard A. StoneAbstract:We present a theoretical study of a variant of the classical Viscous Fingering instability, which occurs when a high viscosity fluid is displaced by a low viscosity fluid in a Hele-Shaw cell. In our system, the Hele-Shaw cell is tapered in the direction of fluid displacement. We consider two tapered Hele-Shaw geometries (rectilinear and radial), which have a constant depth gradient in the flow direction. We find that the presence of a depth gradient can alter the stability of the interface offering opportunities to control and tune Fingering instabilities. In particular, the stability of the interface is now determined by both the viscosity contrast of the fluids and the ratio of the depth gradient to the capillary number of the system. We also demonstrate several applications of our analysis, including the inhibition of Viscous Fingering by controlling the injection flow rate in a radially tapered Hele-Shaw cell.
Yuichiro Nagatsu - One of the best experts on this subject based on the ideXlab platform.
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Experimental evidence of reaction-driven miscible Viscous Fingering.
Physical Review E, 2012Co-Authors: L. A. Riolfo, Yuichiro Nagatsu, Shohei Iwata, Renaud David Maes, Philip M. J. Trevelyan, A. De WitAbstract:An experimental demonstration of reaction-driven Viscous Fingering developing when a more Viscous solution of a reactant A displaces a less Viscous miscible solution of another reactant B is presented. In the absence of reaction, such a displacement of one fluid by another less mobile one is classically stable. However, a simple A+B→C reaction can destabilize this interface if the product C is either more or less Viscous than both reactant solutions. Using the pH dependence of the viscosity of some polymer solutions, we provide experimental evidence of both scenarios. We demonstrate quantitatively that reactive Viscous Fingering results from the buildup in time of nonmonotonic viscosity profiles with patterns behind or ahead of the reaction zone, depending on whether the product is more or less Viscous than the reactants. The experimental findings are backed up by numerical simulations.
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Miscible Viscous Fingering involving viscosity increase by a chemical reaction with moderate Damköhler number
Physics of Fluids, 2011Co-Authors: Yuichiro Nagatsu, Yoshihito Kato, Yusuke Kondo, Yutaka TadaAbstract:In our previous study, we experimentally studied the effects of increased or decreased viscosity of the more-Viscous liquid caused by chemical reactions at a very high Damkohler number, Da (defined as the ratio between a characteristic time of fluid motion and that of a chemical reaction), on miscible Viscous Fingering [Y. Nagatsu et al., “Experimental study on miscible Viscous Fingering involving viscosity changes induced by variations in chemical species concentrations due to chemical reactions,” J. Fluid Mech. 571, 475 (2007)]. In another study, we experimentally studied the effects of decreased viscosity caused by chemical reaction at a moderate Da on the Fingering [Y. Nagatsu et al., “Effects of moderate Damkohler number on miscible Viscous Fingering involving viscosity decrease due to a chemical reaction,” J. Fluid Mech. 625, 97 (2009)]. In the present study, we investigated the effects of increased viscosity caused by chemical reaction at a moderate Da on the Fingering in a radial Hele-Shaw cell. W...
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Miscible Viscous Fingering involving viscosity changes of the displacing fluid by chemical reactions
Physics of Fluids, 2010Co-Authors: Yuichiro Nagatsu, Chika Iguchi, Kenji Matsuda, Yoshihito Kato, Yutaka TadaAbstract:In our previous study, we experimentally studied the effects of changes in the viscosity of the displaced more-Viscous liquid by instantaneous reactions on miscible Viscous Fingering pattern [Y. Nagatsu, K. Matsuda, Y. Kato, and Y. Tada, “Experimental study on miscible Viscous Fingering involving viscosity changes induced by variations in chemical species concentrations due to chemical reactions,” J. Fluid Mech. 571, 475 (2007)]. In the present study, experiments have been performed on the miscible Viscous Fingering involving changes in the viscosity of the displacing less-Viscous liquid by instantaneous reactions in a radial Hele-Shaw cell. We have found that the shielding effect is suppressed and the fingers are widened when the viscosity is increased. As a result, the reaction makes the Fingering pattern denser. In contrast, the shielding effect is enhanced, and the fingers are narrowed when the viscosity is decreased. As a result, the reaction makes the Fingering pattern less dense. These results are ...
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Effects of reactant concentrations on reactive miscible Viscous Fingering
AIChE Journal, 2001Co-Authors: Yuichiro Nagatsu, Toshihisa UedaAbstract:Effects of reactant concentrations on the characteristics of reactive miscible Viscous Fingering in a Hele-Shaw cell at low finger-growth velocity were studied both experimentally and theoretically. The product distribution varies with the variations in the initial reactant concentrations and depends on the location of a reaction zone. When the reaction zone is located in the more-Viscous-liquid region the product concentrates at the fingertips, but when it is located in the less-Viscous-liquid region, the product spreads in a relatively broad area inside the fingers. This significant difference in the reaction pattern resulting from variations in the reactant concentrations is caused by the large difference of molecular diffusivity in the two liquids, that is, of viscosity which is one of the important factors for Viscous Fingering. These results are confirmed theoretically by one-dimensional diffusive–reactive analysis.
Peichun Amy Tsai - One of the best experts on this subject based on the ideXlab platform.
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Manipulation of Viscous Fingering in a radially tapered cell geometry.
Physical Review E, 2018Co-Authors: Grégoire Bongrand, Peichun Amy TsaiAbstract:When a more mobile fluid displaces another immiscible one in a porous medium, Viscous Fingering propagates with a partial sweep, which hinders oil recovery and soil remedy. We experimentally investigate the feasibility of tuning such Fingering propagation in a nonuniform narrow passage with a radial injection, which is widely used in various applications. We show that a radially converging cell can suppress the common Viscous Fingering observed in a uniform passage, and a full sweep of the displaced fluid is then achieved. The injection flow rate $Q$ can be further exploited to manipulate the Viscous Fingering instability. For a fixed gap gradient $\ensuremath{\alpha}$, our experimental results show a full sweep at a small $Q$ but partial displacement with Fingering at a sufficient $Q$. Finally, by varying $\ensuremath{\alpha}$, we identify and characterize the variation of the critical threshold between stable and unstable displacements. Our experimental results reveal good agreement with theoretical predictions by a linear stability analysis.
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Manipulation of Viscous Fingering in a radially tapered cell geometry.
Physical review. E, 2018Co-Authors: Grégoire Bongrand, Peichun Amy TsaiAbstract:When a more mobile fluid displaces another immiscible one in a porous medium, Viscous Fingering propagates with a partial sweep, which hinders oil recovery and soil remedy. We experimentally investigate the feasibility of tuning such Fingering propagation in a nonuniform narrow passage with a radial injection, which is widely used in various applications. We show that a radially converging cell can suppress the common Viscous Fingering observed in a uniform passage, and a full sweep of the displaced fluid is then achieved. The injection flow rate Q can be further exploited to manipulate the Viscous Fingering instability. For a fixed gap gradient α, our experimental results show a full sweep at a small Q but partial displacement with Fingering at a sufficient Q. Finally, by varying α, we identify and characterize the variation of the critical threshold between stable and unstable displacements. Our experimental results reveal good agreement with theoretical predictions by a linear stability analysis.
Jesús Carrera - One of the best experts on this subject based on the ideXlab platform.
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Competition Is the Underlying Mechanism Controlling Viscous Fingering and Wormhole Growth
Geophysical Research Letters, 2020Co-Authors: Y. Cabeza, Juan J. Hidalgo, Jesús CarreraAbstract:This file contains data about wormhole and Viscous finger growth. The contents of the zip file are: DissolutionCapacity.dat: Dissolution capacity versus Peclet and Damkohler numbers. Competition-ViscFing-Da0.dat: Comparison of competition model with Viscous Fingering data. Competition-ViscFing-Da32e-2.dat: Comparison of competition model plus chemistry with Viscous Fingering data. Competition-Wh-Da06.dat: Comparison of competition model with wormhole data. Competition-Wh-Da0.dat: Comparison of competition model without chemistry with wormhole data ViscFing-versus-depth.dat: Number of Viscous fingers versus depth for different number of initial fingers. Wormholes-versus-depth.dat: Number of wormholes depth for different Damkohler x Tau numbers.
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competition is the underlying mechanism controlling Viscous Fingering and wormhole growth
arXiv: Fluid Dynamics, 2019Co-Authors: Y. Cabeza, Juan J. Hidalgo, Jesús CarreraAbstract:Viscous Fingering and wormhole growth are complex nonlinear unstable phenomena. We view both as the result of competition for water in which the capacity of an instability to grow depends on its ability to carry water. We derive empirical solutions to quantify the finger/wormhole flow rate in single-, two-, and multiple-finger systems. We use these solutions to show that Fingering and wormhole patterns are a deterministic result of competition. For wormhole growth, controlled by dissolution, we solve re-active transport analytically within each wormhole to compute dissolution at the wormhole walls and tip. The generated patterns (both for Viscous Fingering and wormhole growth under moderate Damk ohler values) follow a power law decay of the number of fingers/wormholes with depth with an exponent of -1 consistent with field observations
