Relevant bibliographies by topics / Instabilités de Marangoni

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Academic literature on the topic 'Instabilités de Marangoni'

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Published: 4 June 2021
Last updated: 13 February 2022

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Journal articles on the topic "Instabilités de Marangoni"

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GOLOVIN, A. A., A. A. NEPOMNYASHCHY, and L. M. PISMEN. "Nonlinear evolution and secondary instabilities of Marangoni convection in a liquid–gas system with deformable interface." Journal of Fluid Mechanics 341 (June 25, 1997): 317–41. http://dx.doi.org/10.1017/s0022112097005582.

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The paper presents a theory of nonlinear evolution and secondary instabilities in Marangoni (surface-tension-driven) convection in a two-layer liquid–gas system with a deformable interface, heated from below. The theory takes into account the motion and convective heat transfer both in the liquid and in the gas layers. A system of nonlinear evolution equations is derived that describes a general case of slow long-scale evolution of a short-scale hexagonal Marangoni convection pattern near the onset of convection, coupled with a long-scale deformational Marangoni instability. Two cases are considered: (i) when interfacial deformations are negligible; and (ii) when they lead to a specific secondary instability of the hexagonal convection.In case (i), the extent of the subcritical region of the hexagonal Marangoni convection, the type of the hexagonal convection cells, selection of convection patterns – hexagons, rolls and squares – and transitions between them are studied, and the effect of convection in the gas phase is also investigated. Theoretical predictions are compared with experimental observations.In case (ii), the interaction between the short-scale hexagonal convection and the long-scale deformational instability, when both modes of Marangoni convection are excited, is studied. It is shown that the short-scale convection suppresses the deformational instability. The latter can appear as a secondary long-scale instability of the short-scale hexagonal convection pattern. This secondary instability is shown to be either monotonic or oscillatory, the latter leading to the excitation of deformational waves, propagating along the short-scale hexagonal convection pattern and modulating its amplitude.
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BESTEHORN, MICHAEL. "PATTERN SELECTION IN BÉNARD-MARANGONI CONVECTION." International Journal of Bifurcation and Chaos 04, no. 05 (October 1994): 1085–94. http://dx.doi.org/10.1142/s0218127494000794.

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Pattern formation in fluids with a free flat upper surface is examined. On that surface, the Marangoni effect provides an additional instability mechanism. Based on amplitude equations it is shown that phase instabilities confine the region of stable hexagons to a narrow band of wavelengths. On the other hand we developed a numerical scheme that allows for a direct integration of the fully three-dimensional hydrodynamic equations. There we show the evolution of random patterns and the creation and stabilization of defects as well as the instability of hexagonal patterns lying outside the stable band of wave vectors.
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Picardo, Jason R., T. G. Radhakrishna, and S. Pushpavanam. "Solutal Marangoni instability in layered two-phase flows." Journal of Fluid Mechanics 793 (March 14, 2016): 280–315. http://dx.doi.org/10.1017/jfm.2016.135.

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In this paper, the instability of layered two-phase flows caused by the presence of a soluble surfactant (or a surface-active solute) is studied. The fluids have different viscosities, but are density matched to focus on Marangoni effects. The fluids flow between two flat plates, which are maintained at different solute concentrations. This establishes a constant flux of solute from one fluid to the other in the base state. A linear stability analysis is performed, using a combination of asymptotic and numerical methods. In the creeping flow regime, Marangoni stresses destabilize the flow, provided that a concentration gradient is maintained across the fluids. One long-wave and two short-wave Marangoni instability modes arise, in different regions of parameter space. A well-defined condition for the long-wave instability is determined in terms of the viscosity and thickness ratios of the fluids, and the direction of mass transfer. Energy budget calculations show that the Marangoni stresses that drive long- and short-wave instabilities have distinct origins. The former is caused by interface deformation while the latter is associated with convection by the disturbance flow. Consequently, even when the interface is non-deforming (in the large-interfacial-tension limit), the flow can become unstable to short-wave disturbances. On increasing the Reynolds number, the viscosity-induced interfacial instability comes into play. This mode is shown to either suppress or enhance the Marangoni instability, depending on the viscosity and thickness ratios. This analysis is relevant to applications such as solvent extraction in microchannels, in which a surface-active solute is transferred between fluids in parallel stratified flow. It is also applicable to the thermocapillary problem of layered flow between heated plates.
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Samoilova, Anna E., and Alexander Nepomnyashchy. "Feedback control of Marangoni convection in a thin film heated from below." Journal of Fluid Mechanics 876 (August 1, 2019): 573–90. http://dx.doi.org/10.1017/jfm.2019.578.

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We use linear proportional control for the suppression of the Marangoni instability in a thin film heated from below. Our keen interest is focused on the recently revealed oscillatory mode caused by a coupling of two long-wave monotonic instabilities, the Pearson and deformational ones. Shklyaev et al. (Phys. Rev. E, vol. 85, 2012, 016328) showed that the oscillatory mode is critical in the case of a substrate of very low conductivity. To stabilize the no-motion state of the film, we apply two linear feedback control strategies based on the heat flux variation at the substrate. Strategy (I) uses the interfacial deflection from the mean position as the criterion of instability onset. Within strategy (II) the variable that describes the instability is the deviation of the measured temperatures from the desired, conductive values. We perform two types of calculations. The first one is the linear stability analysis of the nonlinear amplitude equations that are derived within the lubrication approximation. The second one is the linear stability analysis that is carried out within the Bénard–Marangoni problem for arbitrary wavelengths. Comparison of different control strategies reveals feedback control by the deviation of the free surface temperature as the most effective way to suppress the Marangoni instability.
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Joo, S. W. "Marangoni instabilities in liquid mixtures with Soret effects." Journal of Fluid Mechanics 293 (June 25, 1995): 127–45. http://dx.doi.org/10.1017/s0022112095001662.

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The stability of a binary liquid mixture heated from above is analysed. The heat transfer is driven by the imposed temperature difference between the horizontal bottom plate and the ambient gas. The mass flux in the layer is induced by the Soret effect. The gravitational effects are ignored, and the instability is driven by solutocapillarity and retarded by thermocapillarity. The interface is allowed to deform, and both the small-wavenumber and the Pearson-type instabilities are studied. Oscillatory instability can exist when the thermocapillary is destabilizing and the solutocapillarity is stabilizing.
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Comissiong, D., R. A. Kraenkel, and M. A. Manna. "Solitary waves on a free surface of a heated Maxwell fluid." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 465, no. 2101 (September 9, 2008): 109–21. http://dx.doi.org/10.1098/rspa.2008.0217.

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The existence of an oscillatory instability in the Bénard–Marangoni phenomenon for a viscoelastic Maxwell's fluid is explored. We consider a fluid that is bounded above by a free deformable surface and below by an impermeable bottom. The fluid is subject to a temperature gradient, inducing instabilities. We show that due to balance between viscous dissipation and energy injection from thermal gradients, a long-wave oscillatory instability develops. In the weak nonlinear regime, it is governed by the Korteweg–de Vries equation. Stable nonlinear structures such as solitons are thus predicted. The specific influence of viscoelasticity on the dynamics is discussed and shown to affect the amplitude of the soliton, pointing out the possible existence of depression waves in this case. Experimental feasibility is examined leading to the conclusion that for realistic fluids, depression waves should be more easily seen in the Bénard–Marangoni system.
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Kovalchuk, Nina. "Spontaneous oscillations due to solutal Marangoni instability: air/water interface." Open Chemistry 10, no. 5 (October 1, 2012): 1423–41. http://dx.doi.org/10.2478/s11532-012-0083-5.

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AbstractSystems far from equilibrium are able to self-organize and often demonstrate the formation of a large variety of dissipative structures. In systems with free liquid interfaces, self-organization is frequently associated with Marangoni instability. The development of solutal Marangoni instability can have specific features depending on the properties of adsorbed surfactant monolayer. Here we discuss a general approach to describe solutal Marangoni instability and review in details the recent experimental and theoretical results for a system where the specific properties of adsorbed layers are crucial for the observed dynamic regimes. In this system, Marangoni instability is a result of surfactant transfer from a small droplet located in the bulk of water to air/water interface. Various dynamic regimes, such as quasi-steady convection with a monotonous decrease of surface tension, spontaneous oscillations of surface tension, or their combination, are predicted by numerical simulations and observed experimentally. The particular dynamic regime and oscillation characteristics depend on the surfactant properties and the system aspect ratio.
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Tönsmann, Max, Philip Scharfer, and Wilhelm Schabel. "Transient Three-Dimensional Flow Field Measurements by Means of 3D µPTV in Drying Poly(Vinyl Acetate)-Methanol Thin Films Subject to Short-Scale Marangoni Instabilities." Polymers 13, no. 8 (April 10, 2021): 1223. http://dx.doi.org/10.3390/polym13081223.

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Convective Marangoni instabilities in drying polymer films may induce surface deformations, which persist in the dry film, deteriorating product performance. While theoretic stability analyses are abundantly available, experimental data are scarce. We report transient three-dimensional flow field measurements in thin poly(vinyl acetate)-methanol films, drying under ambient conditions with several films exhibiting short-scale Marangoni convection cells. An initial assessment of the upper limit of thermal and solutal Marangoni numbers reveals that the solutal effect is likely to be the dominant cause for the observed instabilities.
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BOECK, THOMAS, and ANDRÉ THESS. "Bénard–Marangoni convection at low Prandtl number." Journal of Fluid Mechanics 399 (November 25, 1999): 251–75. http://dx.doi.org/10.1017/s0022112099006436.

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Surface-tension-driven Bénard convection in low-Prandtl-number fluids is studied by means of direct numerical simulation. The flow is computed in a three-dimensional rectangular domain with periodic boundary conditions in both horizontal directions and either a free-slip or no-slip bottom wall using a pseudospectral Fourier–Chebyshev discretization. Deformations of the free surface are neglected. The smallest possible domain compatible with the hexagonal flow structure at the linear stability threshold is selected. As the Marangoni number is increased from the critical value for instability of the quiescent state to approximately twice this value, the initially stationary hexagonal convection pattern becomes quickly time-dependent and eventually reaches a state of spatio-temporal chaos. No qualitative difference is observed between the zero-Prandtl-number limit and a finite Prandtl number corresponding to liquid sodium. This indicates that the zero-Prandtl-number limit provides a reasonable approximation for the prediction of low-Prandtl-number convection. For a free-slip bottom wall, the flow always remains three-dimensional. For the no-slip wall, two-dimensional solutions are observed in some interval of Marangoni numbers. Beyond the Marangoni number for onset of inertial convection in two-dimensional simulations, the convective flow becomes strongly intermittent because of the interplay of the flywheel effect and three-dimensional instabilities of the two-dimensional rolls. The velocity field in this intermittent regime is characterized by the occurrence of very small vortices at the free surface which form as a result of vortex stretching processes. Similar structures were found with the free-slip bottom at slightly smaller Marangoni number. These observations demonstrate that a high numerical resolution is necessary even at moderate Marangoni numbers in order to properly capture the small-scale dynamics of Marangoni convection at low Prandtl numbers.
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Ozen, O., and R. Narayanan. "Comparison of Evaporative Instability with Marangoni Instability." Industrial & Engineering Chemistry Research 44, no. 5 (March 2005): 1342–48. http://dx.doi.org/10.1021/ie0493255.

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Dissertations / Theses on the topic "Instabilités de Marangoni"

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Bergeon, Alain. "Instabilités de Marangoni-Bénard en présence d'effet Soret." Ecully, Ecole centrale de Lyon, 1995. http://www.theses.fr/1995ECDL0023.

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La prediction et la maitrise des instabilites hydrodynamiques constituent un enjeu important dans bon nombre de processus d'elaboration de materiaux a partir d'un bain fondu, car ces instabilites viennent souvent perturber la qualite du materiau produit. Le travail theorique et numerique presente dans cette these porte sur l'instabilite de marangoni-benard dans les melanges binaires sujets a l'effet soret. Ce type d'instabilite est susceptible d'apparaitre lorsqu'une couche de fluide differentiellement chauffee presente une surface libre, siege d'une tension de surface dependant de la temperature et de la concentration. Les fluctuations naturelles de temperature ou de concentration le long de l'interface donnent naissance a des gradients de tension de surface. Ceux-ci generent des forces de surface capables lorsque les processus de dissipation visqueuse et de diffusion sont insuffisants pour endiguer le mouvement, de conduire a la formation d'un ensemble de cellules de convection. Les resultats presentes portent sur les seuils d'apparition de cette instabilite et l'evolution des structures convectives qui en resultent dans des configurations bi- et tri-dimensionnelles de cavites parallelepipediques en l'absence de gravite. Dans ce cadre est d'abord presentee l'analyse lineaire de stabilite de la solution conductive. Celle-ci est conduite analytiquement pour des cavites d'extension horizontale infinie et numeriquement pour des cavites confinees. L'analyse non-lineaire donnant la selection des structures d'ecoulement au dela du seuil est conduite numeriquement et a necessite le developpement d'une methode adaptee dite de continuation. Les resultats se presentent sous la forme de diagrammes de bifurcation qui sont des cartes d'evolution des solutions physiques et mathematiques du systeme avec l'un des parametres adimensionnalises. Ces diagrammes ont donne de nombreuses informations sur la dynamique de notre systeme permettant en outre d'expliquer la disparition ou au contraire la stabilisation de certaines solutions
The prediction and control of hydrodynamic instabilities are important for material processing from a melt, as these instabilities often perturb the quality of the material. The theoretical and numerical work presented in this thesis deal with the Marangoni-Bénard instability in binary mixtures with Soret effect. This type of instability is obtained when a fluid layer differentially heated presents a free surface subjected to surface tension depending on temperature and concentration. The natural fluctuations of temperature and concentration along the interface give surface tension gradients. These gradients generate surface forces which can lead, if viscous dissipation and diffusion are unable to damp the motion, to the formation of convective cells. The results concern the onset of this instability and the evolution of the convective structures which are created in two- and three- dimensional parallelepipedic cavities without gravity. First, the linear stability analysis of the conductive solution is presented. This analysis is performed analytically for laterally unbounded cavities and numerically for confined cavities. The nonlinear analysis giving the selection of flow structures beyond the thresholds is performed numerically with the use of a continuation method which has been developed specifically. The results are presented under the form of bifurcation diagrams which are maps of evolution of the physical and mathematical solutions of the system with regard to the variation of one of the characteristic parameters. These diagrams have given many informations on the dynamic of our system allowing for example to explain the disparition or the stabilisation of some of the solutions
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Dupont, Olivier. "Les instabilités de Marangoni-Bénard: conditions instationnaires en pesanteur normale et réduite." Doctoral thesis, Universite Libre de Bruxelles, 1992. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212931.

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Le, Roux Sébastien. "Effet Marangoni aux interfaces fluides." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S060/document.

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Nous présentons au cours de ce manuscrit diverses expériences de dépôt de tensioactifs solubles dans l'eau à l'interface entre deux fluides. Après quelques développements théoriques, nous étudions l'étalement de tensioactifs solubles déposés à une interface eau/air. Nous présentons au cours de cette partie deux configurations expérimentales dans lesquelles ces molécules exhibent une vitesse caractéristique d'écoulement induit ainsi qu'une distance finie d'étalement dépendant de la CMC du surfactant utilisé, qui se traduit par l'apparition d'une tache centimétrique à la surface de l'eau. Nous mettons alors au point un protocole de mesure simple et rapide de CMC utilisant notre dispositif expérimental. À cet étalement s'ajoutent une déformation verticale de l'interface, la mise en place d'une double recirculation toroïdale, ainsi qu'une instabilité hydrodynamique de surface tout autour de la tache. La deuxième expérience porte sur l'étalement de tensioactifs solubles à une interface eau/huile. Dans cette expérience, les déformations verticales induites par l'étalement peuvent devenir très importantes, si bien que sous certaines conditions cette déformation crée un trou dans la couche d'huile. Nous nous penchons donc sur l'étude de ces déformations verticales, ainsi que sur les caractéristiques de ce cratère. Enfin, la dernière partie traite du dépôt d'une goutte de Triton X-100 à la surface de l'eau. Ce tensioactif possède la propriété de gélifier lorsqu'il est hydraté, ce qui lui permet de flotter. On observe alors un phénomène d'auto-propulsion de la goutte. Nous nous intéressons plus particulièrement à la structure microscopique de cette phase gel, ainsi qu'aux trajectoires erratiques empruntées par la goutte
We report experiments about the deposition of water soluble surfactants at the interface between two fluids. After some theoretical developments, we study the spreading of water soluble amphiphiles at the water/air interface. In this part, we present two experimental setups where these molecules show a typical induced flow velocity, and a finite spreading distance, depending on the CMC of surfactant we use, which results in the apparition of a coronna on the surface of the liquid. We then set up a fast and simple CMC measurement protocole using our experimental setup. This spreading induces also a vertical deformation of the interface, a double toroidal recirculation in the bulk, and a beatiful hydrodynamic surface instability all around the coronna. The second experiment is about the spreading of amphiphiles at the interface between oil and water. In this experiment, the vertical deformations induced by the spreading can become so important that under certain circumstances, we manage to create a hole in the oil layer. We focus on the study of these vertical deformations and on the caracteristics of this hole. Finally, the last experiment is about the deposition of a Triton X-100 drop at the water/air interface. This molecule has the ability to gelify when it gets hydrated, allowing him to float. Then we can observe the self propulsion of the droplet. We focus on the microscopic structure of this gel phase, and also on the erratic trajectories followed by the drop
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Tadmouri, Rawad. "Tensioactifs en système biphasique eau-huile : propriétés, transfert et instabilité de Marangoni." Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1360/.

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Des instabilités hydrodynamiques ont été observées et étudiées pendant le transfert de matière dans deux types de systèmes biphasiques eau/huile. Le premier est un système non réactif impliquant le transfert de deux séries de tensioactifs ioniques (bromure de tétraalkylammonium à longue chaîne (CnTAB, n = 12, 16, 18) et dodécylsulfate de tétraalkylammonium (TAADS)). L'instabilité est, dans ce cas, périodique. Le système bascule alternativement d'un régime de diffusion vers un régime convectif. Le deuxième système est un système réactif, la réaction d'hydrolyse biphasique du chlorure de myristoyle (RCOCl, R = C13H27). Le transfert du chlorure de myristoyle vers la phase aqueuse est induit par la réaction d'hydrolyse qui donne lieu à la formation de composés tensioactifs. Les études réalisées dans la géométrie de la cellule Hele- Shaw ont montré que cette réaction biphasique donne lieu à un régime bien défini de cellules convectives de Marangoni. Notre objectif a consisté dans un premier temps à déterminer de façon quantitative les propriétés physicochimiques de ces systèmes. Nous avons mis au point une méthodologie originale, basée sur la modélisation de données de tension superficielle, permettant de déterminer les propriétés de partage, d'adsorption aux interfaces eau/air et eau/huile et d'agrégation. Nous avons pour les deux séries de composés tensioactifs (CnTAB et TAADS) mis en évidence la formation de microémulsions huile dans l'eau. Nous nous sommes également intéressés aux propriétés cinétiques de transfert et avons observé une dynamique accélérante due à un effet autocatalytique. Pour le système non réactif, cette accélération, observée lors du transfert de la phase organique vers la phase aqueuse, est due à la formation de microémulsions huile dans l'eau. Pour le système réactif, la forme de la cinétique est différente de celle observée pour le simple transfert de tensioactif. La courbe sigmoïde est dans ce cas parfaitement symétrique. Cette observation indique certainement un mécanisme différent du précédent. Il implique également une modification des propriétés de solubilisation de la phase aqueuse mais cette fois non par la formation d'agrégats mais plutôt par la formation de dimères
Hydrodynamics instability have been observed and studied during the mass transfer in two water/oil biphasic systems. The first is a non-reactive system involving the transfer of two series of ionic surfactants (tetraalkylammonium bromide (CnTAB) and tetraalkylammonium dodecylsulfate (TAADS)). In this case, the instability is periodic. The second system is a reactive system, the biphasic hydrolysis of myristoyl chloride (RCOCl). The transfer of myristoyl chloride to the aqueous phase is induced by the hydrolysis reaction leading to the formation of surface-active compounds. Studies in the geometry of the Hele-Shaw cell showed that this biphasic reaction gives rise to a well-defined regime of chemo-Marangoni convection cells. Our objective was initially to determine quantitatively the physicochemical properties of these systems. We have developed a methodology based on the modeling of interfacial tension measurements, to determine the partition and adsorption properties at the water/air and water /oil interface and aggregation. We have showed for the two series of surfactants the formation of oil in water microemulsions. We have also studied the kinetics of transfer and showed a particular dynamic accelerating due to the catalytic effect. For the non-reactive system, this acceleration, observed during the transfer of the organic phase to the aqueous phase, is due to the formation of oil-in-water microemulsions. For the reactive system, the shape of the kinetics is different from that observed for simple transfer of the surfactant. The sigmoid curve in this case is perfectly symmetrical. This observation certainly indicates a mechanism different from above. It also implies a change of solubilization of the aqueous phase but this time not by the formation of aggregates but by the formation of dimers
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Wodlei, Florian. "Self-pulsations of a dichloromethane drop on a surfactant solution." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30188/document.

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Le couplage entre processus physico-chimiques et le transfert de matière ou de chaleur peuvent donner lieu à des structures spatio-temporelles induites par des flux convectifs. Ces flux peuvent résulter de gradients de densité ou de tension superficielle et sont l'expression de la conversion d'énergie chimique en énergie mécanique. Quand la tension superficielle est à l'origine de ces mouvements, les effets correspondants sont connus sous le nom d'effet Marangoni. Ils jouent un rôle dans de nombreuses applications comme les procédés industriels d'extraction en amplifiant notablement la vitesse des processus de transfert. Les systèmes réels, trop complexes, doit être simplifiés par le développement de systèmes modèles afin d'établir au niveau fondamental la théorie sous-jacente à de telles dynamiques. Une succession de régimes dynamiques est observée lors de la dissolution d'une goutte de dichlorométhane (DCM) déposée sur une solution aqueuse de tensioactif (bromure de céthytriméthylammonium, CTAB). La succession remarquable de formes et de mouvements induits est déterminée par la concentration du tensioactif qui joue le rôle de paramètre de contrôle. A faible concentration en CTAB, un mouvement de translation ou des pulsations. Aux concentrations plus élevées, la goutte entre en rotation ou forme des structures polygonales. Bien que chimiquement simple, le système est complexe et implique plusieurs processus physico-chimiques : évaporation, solubilisation, transfert de tensioactifs, adsorption aux interfaces et agrégation. Les effets thermiques et de transport qui en résultent sont à l'origine des variations locales de tension interfaciale donnant lieu aux effets Marangoni. Nous nous sommes concentrés sur le comportement de la goutte quand la concentration en tensioactif conduit au régime de pulsation. Nous avons tout d'abord analysé le comportement de la goutte pendant la période d'induction qui précède le régime instable. L'analyse de la forme de la goutte corrélée à des mesures d'Imagerie par Vélocimétrie de Particules (PIV), ont montré que les flux créés par la dissolution du DCM limitent dans un premier temps l'adsorption du CTAB à l'interface eau/huile. L'instabilité ne démarre que lorsque la dissolution est réduite et que l'adsorption devient effective. La phase d'induction apparait comme une transition lente entre un coefficient d'étalement négatif (goutte ayant la forme d'une lentille) vers un coefficient d'étalement positif qui entraine l'expansion du film et les pulsations suivantes. Ces pulsations sont accompagnées par l'éjection de gouttelettes qui se forment à partir d'un bourrelet apparaissant au bord du film pendant la phase d'expansion. La rupture de ce bourrelet ressemble au phénomène connu sous le nom d'instabilité de Rayleigh-Plateau (RP). Cependant, la longueur d'onde caractéristique de formation des gouttelettes est deux fois plus faible que celle attendue dans le cas d'une instabilité de RP classique. L'origine de cet écart réside dans la modulation du bourrelet avant sa rupture. Cette modulation est en fait déterminée par des ondulations apparaissant à la surface du film et formant des rides en direction radiale. Ces rides pourraient être attribuées à un effet Marangoni thermique connu sous le nom d'instabilité de Bénard-Marangoni. Elles jouent également un rôle important dans la formation de la structure de démouillage hautement organisée décrite dans le dernier chapitre. L'ajout de CTAB dans la phase organique (goutte) donne lieu à des oscillations plus rapides qui, après une phase d'expansion de grande amplitude et l'éjection d'une couronne parfaite de gouttelettes, résultent lors de la phase de démouillage en une structure dont la forme rappelle une fleur. Une interprétation qualitative permettant d'identifier les principaux processus à l'œuvre et basée sur des mesures indépendantes de tension interfaciale apporte une explication des pulsations observées et de l'auto-organisation induite
Far-from-equilibrium systems exhibit a wide variety of spatial and temporal patterns known as dissipative structures. The interplay between physico-chemical processes and mass or heat transfer can give rise to spatio-temporal structures induced by convective flows. These flows may result from density or surface tension gradients. They are the expression of the conversion from chemical into mechanical energy. When surface tension is the driving force, the corresponding effects are known as Marangoni effects. They are at play in numerous applications as extraction processes, oil recovery, and chemical reactors at all scales and noticeably modify transfer rates. The complexity of real systems deserves the development of model systems, essentials to settle, on a fundamental level, the theory governing the related dynamics. A succession of dynamical regimes is observed during the dissolution of a dichloromethane drop deposited on aqueous solutions of a cationic surfactant (cetyltrimethylammonium bromide, CTAB). The remarkable range of shapes and motion patterns that emerges is related to the surfactant concentration, which is used as a control parameter. For low surfactant concentrations, we observe translational motion and pulsations of the drop. At intermediate concentrations the drop transforms and starts to rotate. At higher concentrations polygonal shapes are observed. Although chemically simple and of easy implementation, the system is relatively complex and involves several processes: evaporation, solubilization, surfactant mass transfer, interfacial adsorption and self-aggregation. Thermal and transport effects induced are at the origin of local variations of interfacial tension leading to the Marangoni flows. In this thesis, we focused on the behavior of the dichloromethane drop when the aqueous surfactant concentration (0.5 mM) leads to the pulsating regime. At this concentration, we have first analyzed the behavior of the drop during the induction period that precedes the instable regime. Drop shape analysis, correlated to Particle Image Velocimetry (PIV) measurements, showed that dissolution flows initially hinder adsorption of CTAB at the water/oil interface. The instability is only triggered when dissolution is reduced and water/oil adsorption becomes effective. The induction period appears as a slow transition from an initial negative spreading coefficient (a lens shape drop) towards a positive spreading coefficient that triggers film expansion and following pulsations. These pulsations are accompanied by the ejection of smaller droplets which are formed from a toroidal rim that is created during the expanding phase of the drop. The break-up of this toroidal rim, resembles to what is known as the Rayleigh-Plateau (RP) instability. Nevertheless, the observed characteristic wavelength is a factor of 2 too small in respect to the classical RP instability. We have found the origin of this discrepancy in the fact that modulations that appear on the rim before it transforms into droplets are settled by deformations arising at the surface of the expanding film. They appear as wrinkles that form in the film and may be related to thermal Marangoni effects known as Benard-Marangoni instability. These wrinkles play an important part in the highly organized dewetting structure described in the last chapter of the thesis. The addition of CTAB also in the organic (drop) phase leads to faster pulsations which, after a very high amplitude expanding stage and the ejection of a perfect crown of droplets, result during the film receding stage in the formation of a pattern which symmetry is reminiscent of a flower. A qualitative interpretation aimed at identifying the main processes at play and based on independent surface tension data gives a consistent explanation of the observed pulsations and related self-organized patterns
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Pradines, Vincent. "Instabilités périodiques de Marangoni en système biphasique liquide/liquide : rôle et propriétés de paires d'ions tensioactives." Toulouse 3, 2006. http://www.theses.fr/2006TOU30155.

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Oscillations of the electrical potential and interfacial tension have been studied during mass transfer in water/dichloromethane biphasic systems: CTAB/picric acid and SDS/TAAB for which, the chain length of the tetraalkylammonium was varied (from ethyl to butyl). A detailed analysis of the signals recorded allowed us to confirm the hydrodynamic origin (Marangoni instability) of the oscillations. We have determined the physico-chemical properties of all species involved (partition and adsorption constant, molecular area, and association constant of the ion pairs). For this, measurements of the surface tension, UV/Visible spectrophotometry and mass spectrometry have been performed. For the SDS/TAAB system, we have observed increasing association of TAADS ion pairs with chain length. We have also carried out theoretical calculations (DFT, Ab-initio) to highlight a geometry supporting the hydrophobic interactions between the two ions.
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Trouette, Benoît. "Instabilités de Rayleigh-Bénard-Marangoni, induites par évaporation, en régime transitoire. Applicatons aux solutions polymères." Phd thesis, Université Paris Sud - Paris XI, 2010. http://tel.archives-ouvertes.fr/tel-00598835.

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Dans ce travail nous étudions numériquement le déclenchement d'instabilités thermo-solutales dans le cas du séchage d'une solution polymère. L'évaporation du solvant entraine une baisse de la température et de la concentration du solvant en surface. Ceci peut générer des instabilités thermo-convectives et solutales, induites par les variations de la masse volumique (poussée d'Archimède) et/ou de la tension super ficielle (eff et Marangoni). L'épaisseur du milieu ainsi que les gradients de température et de concentration évoluent au cours du séchage et il s'agit donc d'un problème transitoire. Deux modèles simplifiés sont mis en place, tenant respectivement compte des e ffets thermique et solutal. L'étude porte principalement sur trois points : la détermination du rôle respectif de chaque phénomène, le caractère transitoire du problème, et enfi n l'influence de l'évolution de la viscosité de la solution avec la concentration au cours du séchage sur les seuils de transition entre les régimes conductif et convectif.
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Trouette, Benoît. "Instabilités de Rayleigh-Bénard-Marangoni, induites par l'évaporation, en régime transitoire : application aux solutions polymères." Paris 11, 2010. http://www.theses.fr/2010PA112298.

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Dans ce travail nous étudions numériquement le déclenchement d'instabilités thermo-solutales dans le cas du séchage d'une solution polymère. L'évaporation du solvant entraine une baisse de la température et de la concentration du solvant en surface. Ceci peut générer des instabilités thermo-convectives et solutales, induites par les variations de la masse volumique (poussée d'Archimède) et/ou de la tension superficielle (effet Marangoni). L'épaisseur du milieu ainsi que les gradients de température et de concentration évoluent au cours du séchage et il s'agit donc d'un problème transitoire. Deux modèles simplifiés sont mis en place, tenant respectivement compte des effets thermique et solutal. L'étude porte principalement sur trois points : la détermination du rôle respectif de chaque phénomène, le caractère transitoire du problème, et enfin l'influence de l'évolution de la viscosité de la solution avec la concentration au cours du séchage sur les seuils de transition entre les régimes conductif et convectif
This work aims to study numerically how instabilities are activated in the drying of solvent/polymer solution. Solvent evaporation induces both a cooling and a decrease in solvent concentration at the free surface. Consequently, density variations (buoyancy) and/or superficial tension variations (Marangoni effect) can generate convection into the bulk. Besides, since the temperature and concentration gradients but also the thickness of the solution evolve during the drying, we are dealing here with a full transient problem. For this purpose, two simplified models are established for thermal and solutal regimes respectively. This study mainly focuses on: the transient character of the problem, the role of each phenomenon (thermal/solutal), on one hand, and the impact of the evolution of the solvent mass fraction and by the way of the viscosity of the solution, on the other hand, on the instability thresholds and the flow structure
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9

Géoris, Philippe. "Contribution à l'étude des instabilités de Marangoni-Bénard et Rayleigh-Bénard pour les systèmes multicouches." Doctoral thesis, Universite Libre de Bruxelles, 1994. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212715.

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Assemat, Pauline. "Dynamique non-linéaire des écoulements confinés : application à l'instabilité de Marangoni-Bénard et aux écoulements entre surfaces texturées." Toulouse 3, 2008. http://thesesups.ups-tlse.fr/1225/.

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Le travail porte sur deux problématiques scientifiques : la formation de structures convectives induites par l'instabilité de Marangoni-Bénard et les propriétés de transport des écoulements entre surfaces texturées. Bien que physiquement distincts, ces deux systèmes présentent les points communs d'être assujettis à de fortes contraintes spatiales. Il sont analysés par le biais de la théorie des bifurcations. L'étude de la convection de Marangoni-Bénard a été menée dans des géométries cylindriques à section transverse circulaire et faiblement elliptique. La comparaison des deux situations dans le régime non-linéaire a été menée par l'étude des changements induits sur les diagrammes de bifurcation eux mêmes interprétés par la théorie des bifurcations en présence de symétries. Nous avons ensuite mené l'étude de cette instabilité en présence de mélanges fluides binaires sujets à l'effet Soret et dans des couches fluides bidimensionnelles. Ce travail a révélé la formation de structures convectives spatialement localisées appelées convectons dont nous avons révélé la formation sur un fond d'ondes de plus faible amplitude. Enfin, nous avons étudié les propriétés de transport des écoulements entre surfaces texturées. Le système étudié est confiné transversalement à la direction de l'écoulement ce qui place cette étude dans le contexte de la microfluidique et de l'élaboration de micro-mélangeurs passifs. La simulation numérique et l'analyse des propriétés de transport de traceurs passifs est menée sur les équations issues d'un développement asymptotique faiblement inertiel dans un canal formé d'une succession périodique de cellules texturées
The work focuses on two different physical situations: the convective structures resulting from the Marangoni-Bénard instability and the flow between patterned surfaces. The two systems are spatially constrained and are analysed using dynamical systems theories. Marangoni-Bénard convection has been studied in cylindrical geometries with either a circular or a weakly elliptical cross-section. The comparison of the two situations is carried out in the non-linear regime and the corresponding bifurcation diagrams are analysed using bifurcation theory with symmetries. Two-dimensional Marangoni convection in binary mixtures with Soret effect has also been studied in large periodic domains. The results show the formation of steady convective structures localized in space called convectons and the onset of stable convectons embedded in a background of small amplitude standing waves. Finally, the transport properties of flows in between patterned surfaces under weak inertia influence is studied. The flow is induced by a constant applied pressure gradient and the velocity field is calculated using an extension of the lubrication approximation taking into account the first order inertial corrections. Trajectories of tracers are obtained by integrating numerically the quasi-analytic velocity field. The transport properties are analysed by the study of Poincaré sections and their invariants
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Books on the topic "Instabilités de Marangoni"

1

Alexander, Oron, Duh J. C, and United States. National Aeronautics and Space Administration., eds. Marangoni instability in a liquid layer with two free surfaces. [Washington, DC: National Aeronautics and Space Administration, 1993.

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E, McCaughan Frances, and United States. National Aeronautics and Space Administration., eds. Coupled Marangoni-Benard/Rayleigh-Benard instability with temperature dependent viscosity. [Washington, DC]: National Aeronautics and Space Administration, 1994.

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E, McCaughan Frances, and United States. National Aeronautics and Space Administration., eds. Coupled Marangoni-Benard/Rayleigh-Benard instability with temperature dependent viscosity. [Washington, DC]: National Aeronautics and Space Administration, 1994.

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Coupled Marangoni-Benard/Rayleigh-Benard instability with temperature dependent viscosity. [Washington, DC]: National Aeronautics and Space Administration, 1994.

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Alexander, Oron, Duh J. C, and United States. National Aeronautics and Space Administration., eds. Marangoni instability in a liquid layer with two free surfaces. [Washington, DC: National Aeronautics and Space Administration, 1993.

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Coupled Marangoni-Benard/Rayleigh-Benard instability with temperature dependent viscosity. [Washington, DC]: National Aeronautics and Space Administration, 1994.

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Center, Lewis Research, ed. Convective instability of a gravity modulated fluid layer with surface tension variation. [Cleveland, Ohio]: National Aeronautics and Space Administration, Lewis Research Center, 1998.

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United States. National Aeronautics and Space Administration., ed. Stability and instability of thermocapillary convection in models of the float-zone crystal-growth process: Final report. [Washington, DC: National Aeronautics and Space Administration, 1993.

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Book chapters on the topic "Instabilités de Marangoni"

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Lebon, G. "Some Problems in Marangoni Instability." In NATO ASI Series, 253–69. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-0707-5_20.

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Nadarajah, A., and R. Narayanan. "Comparison Between Morphological and Rayleigh-Marangoni Instabilities." In Dissipative Structures in Transport Processes and Combustion, 215–28. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-84230-6_15.

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Velarde, M. G., and X. L. Chu. "Marangoni Effect, Instabilities and Waves at Interfaces." In Phase Transitions in Soft Condensed Matter, 139–43. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4613-0551-4_12.

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Perez-Garcia, C., P. Cerisier, and R. Occelli. "Pattern Selection in the Bénard-Marangoni Instability." In Springer Series in Synergetics, 232–39. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-73861-6_20.

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Garazo, A. N., and M. G. Velarde. "1D And 2D Nonlinear Evolution Equations For Bénard-Marangoni Convection." In Instabilities and Nonequilibrium Structures IV, 213–23. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1906-1_21.

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Eckert, Kerstin, and André Thess. "Secondary Instabilities in Surface-Tension-Driven Bénard-Marangoni Convection." In Dynamics of Spatio-Temporal Cellular Structures, 163–76. New York, NY: Springer New York, 2006. http://dx.doi.org/10.1007/978-0-387-25111-0_9.

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Lebon, G., P. C. Dauby, and A. Cloot. "Some Problems Raised by Marangoni Instability in Spherical Geometry." In Microgravity Fluid Mechanics, 71–79. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-50091-6_7.

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Benguria, R. D., and M. C. Depassier. "Oscillatory Instabilities in Benard-Marangoni Convection in a Fluid Bounded above by a Free Surface." In Instabilities and Nonequilibrium Structures II, 221–25. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2305-8_17.

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Velarde, M. G., and X. L. Chu. "Interfacial Instabilities, Waves and Solitons Excited by the Marangoni Effect." In Nonlinear Wave Processes in Excitable Media, 435–49. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4899-3683-7_39.

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Muñoz-Bonilla, Alexandra, Maud Save, Laurent Billon, and Juan Rodríguez-Hernández. "Breath Figures: Fabrication of Honeycomb Porous Films Induced by Marangoni Instabilities." In Polymer Surfaces in Motion, 219–56. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-17431-0_10.

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Conference papers on the topic "Instabilités de Marangoni"

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Subramanian, Pravin K., and Abdelfattah Zebib. "Marangoni Instabilities in Microencapsulation." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASME, 2003. http://dx.doi.org/10.1115/imece2003-41377.

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Bhamla, M. Saad, and Gerald G. Fuller. "Video: Placing Marangoni instabilities under arrest." In 68th Annual Meeting of the APS Division of Fluid Dynamics. American Physical Society, 2015. http://dx.doi.org/10.1103/aps.dfd.2015.gfm.v0040.

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Khanwale, Makrand, Hrushikesh Khadamkar, and Channamallikarjun Mathpati. "Video: Marangoni instabilities on rising drop interface." In 68th Annual Meeting of the APS Division of Fluid Dynamics. American Physical Society, 2015. http://dx.doi.org/10.1103/aps.dfd.2015.gfm.v0105.

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Arpaci, V., E. Evren-Selamet, and A. Chai. "Thermocapillary driven flow past the Marangoni instability." In 32nd Aerospace Sciences Meeting and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1994. http://dx.doi.org/10.2514/6.1994-239.

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Pan, Zhenhai, and Hao Wang. "Onset of Benard-Marangoni Instability on a Flat Meniscus in a Microchannel." In ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/mnhmt2012-75222.

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Attention Marangoni instability in a microchannel is of interest in various heat transfer and microfluidic applications. In this work, a numerical study is conducted on a flat meniscus in a square adiabatic microchannel. The evaporative heat flux is uniform, and thus the initial meniscus temperature is uniform. However, the simulations showed that a temperature gradient perpendicular to the meniscus can also lead to an instability that starts a strong Marangoni flow, which should be a type of the Benard-Marangoni instability that was originally observed on a thin liquid layer. A new expression of the Marangoni number (Ma) is derived for the Benard-Marangoni instability in a microchannel. The threshold Ma values are obtained, providing guidance for microfluidic design.
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Birikh, R., O. Shklyaev, V. Briskman, and M. Velarde. "Marangoni instability of liquid with partially free surface." In 36th AIAA Aerospace Sciences Meeting and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1998. http://dx.doi.org/10.2514/6.1998-654.

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Pan, Zhenhai, and Hao Wang. "Marangoni Asymmetrical Instability in a T-Junction Microchannel With an Open Outlet." In ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/mnhmt2012-75164.

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The Marangoni convections in microchannels are of interest in various applications such as heat transfer, material and microfluidics. In this paper, the Marangoni asymmetrical instability at a T-junction in a microchannel is investigated. The T-junction is formed by a main channel which water going through and a side channel which is open to the ambient. A convex meniscus is formed in side channel near the T-junction, evaporating/volatizing into the ambient. The consumption of water due to the evaporation is compensated by the supply from the main channel. It is found that for weak evaporations, the evaporation-induced Marangoni convections are symmetrical. However, when the evaporation reaches a critical intensity, the symmetrical Marangoni convection becomes unstable and evolves into an asymmetrical one, with one single vortex under the meniscus. More interestingly, the vortex creates a steady convection through the main channel from its one end to the other, just like a pump. The pumping flow rate is found linearly correlated with the Marangoni number at the T-junction.
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Hillaire, Keith, Michael Dickey, and Karen Daniels. "Video: Marangoni Fingering Instabilities in Oxidizing Eutectic Gallium Indium." In 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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Liu, Qiu-Sheng, Rong Liu, Zhi-Qiang Zhu, Jia-Ping Yan, and Shu-Ling Chen. "Evaporative and convective instability in the two-layer Marangoni-Bénard." In 57th International Astronautical Congress. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2006. http://dx.doi.org/10.2514/6.iac-06-a2.4.02.

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Xu, B., X. Ai, and B. Q. Li. "Be´nard-Marangoni Instability in an Open Vertical Cylinder With Lateral Heating." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81857.

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A linear stability analysis of Rayleigh-Be´nard-Marangoni flow of low Prandtl number fluid contained in an open vertical cylinder is presented. The cylinder is heated laterally and is cooled at top surface by radiation. Governing equations of the flow are solved for axisymmetric base flow using higher order finite difference scheme. Small perturbation was applied to the obtained base flow to determine the critical Marangoni number and Grashof number at which the axisymmetry is broken. The eigenvalue matrix equation is solved using linear fractional transformation with banded matrix structure taken into account. It is found that the thermocapillary effect stabilizes the convective flow driven by buoyancy.
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