WorldCat Identities

Lorenceau, Elise

Overview
Works: 29 works in 32 publications in 2 languages and 130 library holdings
Genres: Handbooks and manuals 
Roles: Author, Other, Opponent, Thesis advisor
Publication Timeline
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Most widely held works by Elise Lorenceau
Thermodynamique : aide-mémoire by Élise Lorenceau( Book )

3 editions published in 2003 in French and held by 95 WorldCat member libraries worldwide

Interfaces en grande déformation : oscillations, impacts, singularités by Élise Lorenceau( Book )

2 editions published in 2003 in French and held by 3 WorldCat member libraries worldwide

Moussage des fluides complexes : dynamique de la formation des bulles dans des fluides à seuil en géométries confinées by Benoît Laborie( )

1 edition published in 2015 in English and held by 2 WorldCat member libraries worldwide

We study the formation of bubbles inside yield stress fluids (liquid when the applied stress is above the yield stress, and solid otherwise) using mill fluidic geometries (T-junctions, flow focusing devices) made of axisymmetric channels, and manufactured by stereo lithography. We show that dispersing bubbles in simple yield stress fluids (concentrated emulsions, and carbopol gels) is possible by taking advantage of the yield stress over the capillary stress, and due to the squeezing of the gas thread by the core of the yield stress fluid flow at imposed flow rate. The observed behaviour is reminiscent of the geometrical operating regime in 2D flow-focusing devices for Newtonian fluids. We investigate the different operating regimes that occur when the yield stress fluid flow rate and the gas pressure are imposed. We report that, for these inlet conditions the production is unsteady, which comes from the hydrodynamic feedback induced by the formation of each bubble on the gas flow rate. The regime eventually breaks down when all bubbles coalesce. This is due to the transfer between the liquid plugs separating each bubble and the thin film located on the channel wall. Thus, we study the deposition of yield stress fluid on the wall of capillary tubes. Indeed, this often occurs for yield stress fluids flowing in confined geometries on smooth surfaces. The results with no-slip are well described by a classical scaling law (internal stresses balanced by capillary pressure gradient). When there is wall slip, we show that there are three regimes that depend on the stress state of the system, and set the bubbles' shape observed for unsteady regimes. Finally, different regulation methods (pressure, pulsated flows) allow to obtain steady regimes. They are characterized (gas volume fraction, bubble formation time) and we show that they allow to obtain yield stress fluid foams. Thus, identifying pathways for potential steady-state controlled production of aerated yield stress fluids at large scale
MEMS à veine fluidique intégrée pour la caractérisation et la pesée d'échantillons liquides by Céline Hadji( )

1 edition published in 2016 in French and held by 2 WorldCat member libraries worldwide

MEMS and NEMS allow sensitive and precise mass detection consistent with micro- and bio- objects analysis. These systems are promising for biomedical research and particle metrology, and can be easily integrated in miniaturized multifunctional systems. Thererfore, characterization in liquid media remains tricky due to viscous dissipation consequent to the movement induced in the fluidic environment.In order to overcome this technological lock, our laboratory previously designed and fabricated specific MEMS devices for fluidic analysis; these thin plate resonators with and embedded microchannel are actuated in liquid media, with four capacitive electrodes providing both actuation and detection. The circulating fluid mass can be precisely measured by monitoring the device's resonant frequency. The long-term objective is to be able to detect and weigh one single particle transported by the fluid.Two main objectives were fulfilled during these three years. First, the MEMS behaviour in presence of various liquids was evaluated, providing a fine-grained analysis of their performances as mass sensors. The measured resolution of our sensors is about a few g.L-1 with a sensitivity of 100 Hz.(g.m-3)-1.Meanwhile, a new generation of NEMS sensors with innovative features was designed; the objective is to decrease the effective mass and reduce the frequency noise, both for a better mass resolution.This thesis includes four chapters. The first one consists in a review of the existing techniques for particles characterization in fluid as well as MEMS and NEMS solutions for particles metrology described in the litterature. The second part of the manuscript presents the results of the experimental characterizations carried out on the first generation of sensors. The third chapter gathers the conclusions of these measurements and gives an outlook on possible improvements on both the design and the characterization of the sensors. At last, the fourth part describes the new generation of devices and discusses their characteristics in terms of expected resolution and applications
Etude des propriétés de transport de mousse dans des modèles de milieux poreux by Alexis Mauray( )

1 edition published in 2017 in French and held by 2 WorldCat member libraries worldwide

In enhanced oil recovery (EOR), foams are injected in porous media to improve oil recovery efficiency. The objective is to limit viscous fingering thanks to the high effective viscosity of the foam at low capillary number Ca. Foam is produced by the co-injection of a gas and a solution of surfactants. This thesis focuses on foam formation and transport mechanisms in model porous media using a heterogeneous micromodel made in NOA. Foam formation is studied using two different approaches. The first one consists in studying a co-injection of two fluids thanks to a jet flowing in the center of the system. This experiment shows that the less wetting fluids is dispersed in the other one when the capillary number is higher than 10-5. A second set of experiments is conducted by injected a pre-formed train of big bubbles in model a porous media. The bubbles divide until they reach a diameter of the order of to the pore size, for high enough capillary numbers Ca. Besides, we studied the transport properties of foam in similar model porous media. Direct measurements show that the pressure drop induces by the flow can be at Ca=10-6 as high as 3000 times the pressure corresponding to water injected at the same injection flow rate. This ratio decreases with capillary number. An analysis of the preferential paths by direct observations shows that, for low relative gas flow rate, only a few paths are active. However, an increase of the capillary number or if relative gas flow rate leads to a homogenization of the flow in the medium. Thanks to different simple models of straight or wavy channels, we measure that the pressure drop induced by a single bubble is in good agreement with Bretherton's law, and scales as Ca2/3. However, in wavy channels the pressure drop due to a single bubble deviates from this prediction and exhibits a plateau at Ca lower than 10-4. In this regime, the motion of the bubble is usually intermittent. Finally, we focus on foam formation and transport properties in presence of oil. Our observations lead to the conclusion that for our setup and surfactant formulations, oil has a negligible influence
Hydrodynamics of oil in contact with an aqueous foam : wetting, imbibition dynamics and flow in rough confined media by Rémy Mensire( )

1 edition published in 2016 in English and held by 2 WorldCat member libraries worldwide

The extraction of raw materials from the soil for energetical (enhanced oil recovery) and environmental purposes (soil remediation) is the subject of intense fundamental and applied research. This field is related to other important topics, such as carbon sequestration and hydraulic fracturing. The goal is to find fewer destructive, as well as energy and material-saving methods. These techniques should also be cost-effective and more efficient. To find a substitution to conventional means, we study an alternative method that puts aqueous foams on the map as the extraction material. Aqueous foams are often used in numerous daily applications, such as cosmetics and detergency, but also in less known fields, such as the decommissioning of nuclear power plants and the oil industry. Thus, surfactants and gas are commonly injected into the soil to improve the recovery processes of oil. We explain two extraction mechanisms that we quantify in terms of efficiency and stability. On one hand, the foam is able to absorb oil, similarly to a solid sponge. On the other hand, when a flow of foam is induced, the foam can entrain oil confined in the roughness of a surface by shearing the oil-water interface. Our work especially lies on a theoretical and experimental analysis, which is multiscale, static and dynamic. We systematically vary the geometrical parameters (oil configuration, bubble size and liquid fraction in the foam) and the physical and chemical parameters (interfacial tensions, interfacial rigidity and viscosity)
Contribution à la caractérisation des processus d'entraînement d'air dans les circuits d'aménagements hydro-électriques by Grégory Guyot( )

1 edition published in 2019 in French and held by 2 WorldCat member libraries worldwide

We study the entrainment of air created by large-dipped jets. Direct applications in the field of hydroelectricity are energy optimization of plants, environmental management around infrastructures and prediction of extreme flood impacts downstream of dams. For such applications, it is necessary to quantify the penetration depth of the bubble cloud, predict the distribution of bubbles and the amount of air entrained. Predictive models describing these three points would be key engineering tools. The literature review shows that many models, particularly those applied to penetration depth or entrained air flow, exist but are limited to a narrow range of parameters. A first experiment was carried out on circular jets with a diameter of about ten centimeters and a drop length of 2.6 m. Comparison of the results with the existing models reveals that these models do not correctly capture the penetration depth, the size of the generated bubbles or the entrained air flow rate. This experiment shows that the jets flap and have an aerated structure at impact, with significant corrugations. In a second smaller scale experiment, we have characterized the influence of the jet movement on the penetration depth. It appears that the oscillation of the jet can lead to a decrease of the penetration depth, but this influence is not sufficient to explain the differences between experiments and models in the large scale experiment. We then designed and operated a third experiment to analyze jets with nozzle speeds between 2 and 30 m/s, nozzle diameters between 24 and 213 mm for a drop height of about 10 m. It is also possible to investigate bubble clouds with this experiment, since the jets are received in a 5 m diameter pit with a depth of up to 23 m. The cross-comparison of measurements made by analyzing high-frequency videos of jet drop, force at impact and optical probe measurements in bubble clouds evidence that the state of the jet at impact has a significant influence on air entrainment. We clearly identify jets with different shapes and air flows than those previously studied. Our analysis also allows us to propose a simple model without any adjustment parameters, based on a balance of forces applied to the bubble cloud. This model predicts the penetration depth of the bubble cloud for a wide range of jet scales
Mécanismes et dynamiques d'interactions entre grains et liquide : du matériau granulaire sec au mélange saturé by Guillaume Saingier( )

1 edition published in 2018 in French and held by 1 WorldCat member library worldwide

Les matériaux granulaires sont omniprésents, tant dans la nature que dans l'industrie ou dans notre vie quotidienne. Les mélanger à un liquide constitue une opération de base dans de nombreux procédés industriels. Néanmoins, la compréhension et la modélisation des mécanismes d'échanges de liquide et de grains impliqués dans le mélange restent encore méconnus. Dans cette thèse, nous considérons les mécanismes d'interactions apparaissant à l'interface entre un matériau granulaire contenant une quantité variable de liquide et un écoulement de grains secs. En fonction de la quantité de liquide, la phase granulaire humide est soit érodée par l'écoulement sec, soit capte des grains par accrétion granulaire, soit transfère du liquide de la phase humide à la phase sèche par imprégnation. Dans un premier temps, nous nous intéressons aux mécanismes et aux dynamiques d'accrétion granulaire observés lors de l'impact d'un jet dilué de grains secs sur un substrat granulaire saturé en liquide. Nous mettons en avant le rôle du liquide aux interfaces dans la dynamique de croissance et les sources de dissipations énergétiques responsables de la capture des grains secs. Une expérience d'accrétion dans un écoulement dense et cisaillé permet ensuite d'étudier l'influence des propriétés de l'écoulement sur la dynamique de capture et d'établir une loi d'accrétion générale. Une configuration d'accrétion d'un agrégat isolé au sein d'un écoulement granulaire en tambour tournant permet enfin d'étendre notre étude au cas des matériaux granulaires non saturés en liquide, croissant par accrétion avant de s'éroder. Dans un second temps, nous étudions l'imprégnation dans un jet granulaire dense pénétrant dans un réservoir de liquide. En modélisant l'entrée des grains dans l'eau comme l'imprégnation d'un matériau poreux, nous mettons en évidence une relation entre la forme du front d'imbibition et la vitesse d'immersion, et caractérisons l'effet des propriétés physico-chimiques des grains. Ces travaux constituent une avancée dans la compréhension des phénomènes locaux impliqués dans le mélange entre grains et liquide et de la transition d'un milieu granulaire sec à humide
Séchage des matériaux de chaussée traités à l'émulsion de bitume by Marie Goavec( )

1 edition published in 2018 in French and held by 1 WorldCat member library worldwide

The preparation of cold mix asphalts, composed of aggregates and bitumen emulsion, represent a substantial economic and environmental potential but the presence of water delays the strengthening of the material. Our objective is to understand how the mix dries and how this affects its properties. The drying of pure liquids in simple porous media has been extensively studied : a constant drying rate period as well as a homogeneous distribution of water are observed until 90% of the water has been extracted; afterwards the drying rate decreases. Studies have shown that the drying of complex fluids (ionic solutions, suspensions, gels) is very different due to the transport and/or accumulation of the fluid's non-vaporizable elements. We chose to study first the drying of the complex fluid i.e. the bitumen emulsion as well as silicone oil emulsions to understand better the drying mechanisms, then the drying of the complex fluid in a porous media. We used Magnetic Resonance Imaging (MRI) to monitor the internal characteristics of our systems. This allowed us to show that water is extracted uniformly over the drying emulsion's entire thickness ("approx"cm), leading to the progressive droplet compaction and deformation. However, a water concentration gradient forms near the free surface, which ultimately slows the drying as droplets coalesce. We then show that the drying rate of a porous medium initially saturated with emulsion decreases from the beginning of drying. The rapid formation and progression of a dry area in the porous medium and the absence of bitumen transport partly explain this but it is very likely that the bitumen emulsion's drying characteristics contribute to the decreasing drying rate
Transferts (imbibition, séchage) dans des matériaux bi-poreux multifonctionnels by Thibault Lerouge( )

1 edition published in 2019 in French and held by 1 WorldCat member library worldwide

Some multi-scale building materials, like wood, hemp concrete or daub, exhibit high potential properties in terms of hygrometric diffusion (moisture expelling out of a house). In order to get a better insight into those properties, we investigate fluid transportation (soaking/drying) in doubly porous model systems based on polymeric materials envisioned by the double porogen templating approach. They are elaborated with controlled hydrophilicity and various large pore (LP) morphologies within the small pores matrix (SP): cubic or spherical, dispersed or connected by sharp-edged or smoother constrictions. We identify two categories of biporous structures leading to very diverging properties. Firstly, when dispersed large pores are included within the SP matrix, the liquid penetrates in the microporous matrix and the large pores absorb little to no water, and confining air inside them. Regardless the volume ratio of dispersed LP, the rising front is well described with different fluids by the classical Washburn theory inside the matrix only. On the other hand, when the large pores constitute a connected network, a competition between the imbibition within both porous networks (microporous matrix and macroporous network interacting with each other) determine the imbibition mechanism. If the rising of capillary front is fast in the macroporous network (smooth connexions between LP), it dominates the imbibition process, and the liquid can be drained by the smaller pore size close to it. In contrast, if the imbibition is slow in the macroporous network (sharp-edged constrictions between LP), then the microporous matrix controls the dynamic of soaking, and can speed it up with synergetic action highlighted by two distinctive rising fronts. The drying of those saturated biporous materials is investigated with 1H NMR relaxation and contraction monitoring. We demonstrate that drying mechanisms depends on the connectivity of large pores inside the microporous matrix too. Dispersed LP are homogeneously emptying first, resulting from a compression induced by the capillary pressure, whereas a connected LP network is emptying first too, but heterogeneously pore after pore. The drying rate is still constant in both cases during the majority of the desaturation
Hydrodynamique des films liquides hétérogènes by Quentin Magdelaine-Guillot de Suduiraut( )

1 edition published in 2019 in French and held by 1 WorldCat member library worldwide

Revêtir une surface d'un film mince permet de lui conférer de nouvelles propriétés, comme en réduire les reflets ou améliorer sa résistance aux rayures. Une méthode pour produire ces revêtements est le dépôt par voie liquide : elle consiste à couvrir la surface avec un matériau dispersé dans un liquide puis à le sécher. Cette méthode permet de fonctionnaliser efficacement et rapidement de grandes surfaces. Bien qu'attrayante pour l'industrie verrière, la perspective d'une fonctionnalisation par voie liquide se heurte actuellement à l'apparition de défauts dans le film lors de son séchage, notamment des variations d'épaisseurs sur de grandes distances. Ces imperfections détériorent l'esthétique et les propriétés optiques de la surface. Dans cette thèse, nous apportons un éclairage sur l'apparition de ces défauts, en étudiant les écoulements générés lors du séchage de films liquides de mélanges binaires. En effet, l'évaporation du solvant peut induire des variations de composition qui génèrent en retour des gradients de tension à la surface du film qui le déstabilisent. La combinaison d'expériences modèles, de modélisations théoriques et de simulations numériques ont permis de mettre en évidence et de décrire quantitativement plusieurs régimes, qui correspondent aux différents effets limitant l'instabilité : la pesanteur, la pression de Laplace, l'homogénéisation latérale par diffusion des composées dans le film ou au contraire la stratification verticale de ces composés, causée par l'évaporation. Une étude indépendante a été menée sur la génération de trains de bulles lorsque de l'air est lentement injecté dans un bain
Moussabilité des mélanges d'huiles by Mélanie Arangalage( )

1 edition published in 2018 in French and held by 1 WorldCat member library worldwide

Parmi les effets stabilisant les mousses produites sans espèces tensioactives, les écoulements Marangoni jouent un rôle important. Nous avons donc mis au point une expérience permettant d'étudier ces écoulements et permettant de tester avec une grande sensibilité l'adsorption d'espèces à une interface liquide/gaz. Nous nous sommes ensuite intéressés à la moussabilité des mélanges binaires d'huiles, en l'occurrence les mélanges alcane/toluène. Même si ces espèces prises séparément ne moussent pas, le mélange des deux peut présenter une moussabilité importante. En effet, dans les mélanges considérés, la proportion des deux espèces à l'interface avec l'air n'est pas la même que celle dans le volume du mélange, les sites à l'interface liquide/gaz n'ayant pas les mêmes énergies que les sites en volume. Une modification de l'épaisseur d'un film liquide, qui se traduirait par une modification du rapport du nombre de sites accessibles par les molécules surface sur volume, est ainsi défavorisée. Enfin, nous avons étudié la moussabilité de systèmes modèles du brut contenant des asphaltènes qui sont des espèces colloïdales endogènes des bruts présentant des propriétés interfaciales connues aux interfaces eau/huile et solide/liquide. En utilisant le montage développé pour étudier l'effet Marangoni, nous démontrons qu'aux concentrations inférieures à 5wt% les asphaltènes ne s'adsorbent pas significativement aux interfaces liquide/gaz. Toutefois, nous montrons que la stabilité des mousses de mélange d'huiles est accrue par la présence d'asphaltènes : nous suggérons que cet effet résulte de la pression osmotique induite dans les films liquides par les agrégats colloïdaux d'asphaltènes
Multi-Scale Study of Foam Flow Dynamics in Porous Media by Christopher Yeates( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

Pour ce travail, nous utilisons un micromodèle à haute complexité et à structure fixe pour faire une série d'expériences en variant la vitesse d'injection, la qualité de la mousse, les distributions de taille de bulles d'injection, et la méthode d'injection. Nous mettons en œuvre un suivi individuel de bulles pour associer les propriétés d'écoulement aux propriétés de taille de bulles ainsi que les caractéristiques structurelles du milieu poreux. Nous proposons de nouveaux outils pour décrire l'écoulement d'un point de vue global et local de différentes manières. Nous établissons des comportements spécifiques à chaque taille de bulle, en montrant que les bulles des mousses piégées sont plus probables d'être de taille inférieure aux tailles de bulles moyennes, alors que les mousses en mouvement accèdent elles-mêmes à différents chemins d'écoulement selon les tailles de bulles. Les bulles plus volumineuses s'écoulent en majorité dans des chemins préférentiels à haute vitesse, généralement parallèles au gradient de pression, mais les petites bulles sont transportées en supplément à l'intérieur de chemins transversaux liant les chemins préférentiels. Ailleurs, pour nos données nous démontrons l'importance supérieure de la fraction de mousse piégée vis-à-vis de la densité de bulles quant à l'explication microscopique de la viscosité apparente, malgré une contribution des deux. Nous caractérisons structurellement les zones piégées à répétition, comme étant soit des zones à faible coordination de pore, de faible taille de seuil d'entrée, d'orientation de seuil désavantageuse, ou une combinaison de ceux-ci. Les zones à fort écoulement échappent à une caractérisation en termes de paramètres de structure locale et nécessitent une considération de l'information des différents chemins traversant la totalité du modèle. À ce but, afin de décrire les zones à fort écoulement, nous développons un modèle générant des chemins, utilisant une représentation en graphe du milieux poreux, basé sur une décomposition initiale en pores et seuils, qui intègre seulement les notions de taille de seuil et d'orientation de seuil relatif au gradient de pression pour caractériser les chemins
Écoulements et écrasements de fluides : effet du mouillage et de la rhéologie by Jérémy Ferrand( )

1 edition published in 2017 in French and held by 1 WorldCat member library worldwide

The draining of a tank through an orifice was described by Torricelli almost 400 years ago. His model does not provide for any wetting effect of the flowing fluid on the drilled plate. This thesis shows experimentally that the effect of wetting on the flow rate is important for Newtonian fluids with low viscosity in the case of an orifice the size of which is comparable to the capillary length. A model calculating the kinetic energy variation within the meniscus at the outlet of the hole allows us to account for experimental observations. Unknown jet instability also appears at the outlet of the hole; this is the oscillation of the meniscus triple line that is causing it. The relations of dispersion of the excitation frequency as well as that of the secondary frequencies appearing along the jet have been established.This investigation was supplemented by flows of both viscous and viscoelastic fluids. For viscous fluids, the perfect fluid model is corrected based on our experiments. For viscoelastic fluids, experiments show that there is competition between viscous dissipations and elastic effects throughout the flow. The prediction of both effects is challenging. We show situations where elastic effects dominate, allowing a polymer solution to flow faster than water.Finally, a second experimental set-up was build for compressing complex fluids between two parallel glass plates. Visualization, both position and normal force measurements, allow a better understanding of the behavior under normal stress of systems such as foams, emulsions, gels
Injection de tensioactif pour la récupération assistée du pétrole : implication sur les lois régissant les écoulements eau-hydrocarbure-tensioactif en milieu poreux by Thomas Cochard( )

1 edition published in 2017 in French and held by 1 WorldCat member library worldwide

L'objectif principal de ces travaux de thèse est l'étude expérimentale de la mobilisation de l'huile dans le cadre de la récupération assistée du pétrole à base de tensioactif dans un milieu poreux en deçà de la saturation en huile résiduelle. A saturation en huile résiduelle, le réseau d'huile est déconnecté et constitué de ganglions dans l'ensemble du milieu poreux. Cette huile résiduelle est difficile à produire dans les conditions classiques de récupération du pétrole à cause du piégeage capillaire des ganglions, piégeage corrélé à la tension interfaciale entre l'huile et l'eau. Le déplacement de la solution de tensioactif et sa caractérisation a été réalisé au travers d'injections en milieux poreux naturels. L'étude a été réalisée dans un premier temps en conditions monophasiques, c'est-à-dire en absence d'huile. Les courbes de percée ont été analysées pour étudier les paramètres de dispersivité et d'adsorption des échantillons. Les expériences sont ensuite utilisées pour améliorer la modélisation du transport du tensioactif en milieu poreux. Pour le cas diphasique, nous avons développé un système microfluidique avec une géométrie de pore variable, le plus représentatif possible d'un milieu poreux naturel. Il s'agit dans les expériences d'injecter un petit ganglion d'huile à travers un canal central et de balayer la puce microfluidique avec la solution tensioactive dans des conditions contrôlées. L'objectif est d'étudier le déplacement du ganglion d'huile au sein du micromodèle. De nouveaux mécanismes sont identifiés et une voie de modélisation des phénomènes physique est proposée
Rhéologie d'interface liquide/air chargées de grains : vers la consolidation d'un milieu aéré by Yousra Timounay( )

1 edition published in 2016 in French and held by 1 WorldCat member library worldwide

Les mousses liquides sont dans un état métastable. Un moyen de les stabiliser est d'y incorporer des particules solides. Lorsqu'elles sont hydrophobes, ces particules s'attachent aux interfaces liquide-air de la mousse et changent radicalement la rhéologie des films séparant les bulles. L'objectif de cette thèse est d'étudier expérimentalement deux composants élémentaires des mousses chargées en particules, à savoir les films et les bulles. La rhéologie des films particulaires est sondée grâce à des expériences d'éclatement et de compression alors que la résistance des bulles armurées est étudiée en faisant varier leur pression interne. En utilisant l'imagerie rapide, nous montrons d'abord que les particules qui pontent les deux interfaces du film peuvent inhiber l'ouverture d'un trou et que pour les autres configurations, la dynamique de rétraction peut être décrite par un équilibre inertio-capillaire pour des fractions surfaciques en particules <0.6 environ. L'étude de la dynamique de rétraction des films particulaires par Particle Image Velocimetry a permis de les caractériser par une viscosité effective qui diverge à la transition de jamming. De plus, les films particulaires flambent à fraction surfacique en particules élevée indiquant une transition d'un comportement liquide vers un comportement solide. En ce qui concerne les bulles particulaires, nous avons montré l'existence de pressions critiques 10 fois plus grandes que la pression de Laplace avant que les bulles ne se déforment aussi bien en dépression qu'en surpression ; la tension effective dans le plan de la coque granulaire est donc 10 fois plus importante que la tension dans un film liquide. Une fracture, correspondant à l'étirement du film liquide, est par ailleurs observée sur les bulles particulaires en surpression. En adoptant une approche élastique, le critère de Griffith permet de retrouver le bon ordre de grandeur de la pression de fracture
Wetting and evaporation of human blood in relation to forensic analysis by Fiona Smith( )

1 edition published in 2018 in English and held by 1 WorldCat member library worldwide

The physics behind wetting and drying of blood is not yet completely understood. In the context of a collaborative project, new techniques have been developed to provide evidence for investigators in crime solving. Given that blood is a complex fluid, the major aim has been to investigate the dynamics involved in the patterns of stain formation. Interest is focused on passive stains, which result from the action of gravity in dripping or blood flow accumulation. In the case of drip stains, the impact behaviour of complex fluid droplets, despite many studies, raises much debate. Although the drying dynamics of a deposited drop of blood were already studied, this is not the case for drops of blood impacting perpendicularly a surface, falling from a certain height. Beside this, until the present work, little attention has been paid to the dynamics controlling the drying of blood pools. In both situations, the influence of different parameters such as substrates, humidity and temperature are examined. Empirical relations are established between final dried blood patterns and the generating mechanism, yielding possible application in blood pattern analysis for forensic investigations. Finally, using inverse methods, the empirical relations allow estimating an impact velocity, for dried drip stains
Microsystèmes pour la génération et la caractérisation de fluides complexes by Maximilien Stoffel( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

This thesis focuses on the creation and characterization in situ of complex fluids in confined geometry. The aim is to build systems capable of generating and characterizing complex fluids, such as biphasic dispersions (emulsions, foams), or fluids mixtures.The first part of this thesis focuses on the modeling and implementation of a new microgenerator to create dispersions with a diameter below 10 um and with a coefficient of variation close to 1% (state of the art).Then we fabricated a microrheometer to study the rheology of such fluids. The characterization of this device led us to use several methods of sending controlled fluid (independent control of flow or pressure), and the use of several types of fluids (Newtonian and non-Newtonian) revealed results in line with our theoretical expectations. This study also led us to use a micromixer in order to generate variables viscosities fluid that we measured using microrheometer. This allowed us to quickly check in a high-throughput experience, results obtained by others with conventional fashion published in the literature. The system we have developed will make it extremely useful for the study of the viscosities of dissimilar fluids mixtures, offering a versatile tool in this field of research remains largely empirical.Finally, we realized a new type of microrheometer equipped with an integrated complex fluids generator. Work carried out on this first version have optimized the geometry and define reliable methods of manufacture, which opens exciting prospects in the near future in order to achieve fully integrated systems for the study of different dispersions types
Friction and Elastohydrodynamic Measurements using Atomic Force Microscope by Muhammad Arshad( )

1 edition published in 2021 in English and held by 1 WorldCat member library worldwide

The studies of fluid flow at nanoscale has shown significant rise due to its potential applicability in different fields including soft matters, medical sciences, mechanics and engineering. In this work, we have used the colloidal AFM in dynamic mode to study the rheological properties of thin polymeric films and the lubricated friction between polystyrene microspheres.We have reported contactless measurement of viscoelastic rheological properties of polymer thin film. The mechanical response is measured as a function of the liquid gap thickness for different oscillation frequencies. Our measurements reveal an elastohydrodynamic coupling between the flow induced by an oscillating colloidal probe and the viscoelastic deformation of the polymer film. We have obtained loss and storage moduli of the film and the data are quantitatively described by a viscoelastic lubrication model. The frequency-dependent loss and storage moduli of soft thin PDMS film are in good agreement with the Chasset-Thirion theory. Our measurements demonstrate that contactless colloidal probe methods are powerful tools that can be used for probing the soft interfaces over a broad range of frequencies.The second part of thesis is dedicated to the rheology of non-Brownian suspensions with a focus on the role of inter-particle friction in shear-thinning behavior. To this aim, AFM is used to measure friction coefficient between polystyrene microspheres to highlight the close link between the microscopic friction properties and the macroscopic rheological properties of the suspensions. The normal and friction forces between two approaching microspheres is measured by recording the deflection and the twist produced in the colloidal probe, respectively. The friction coefficient of polystyrene microspheres is measured for different normal loads. The inter-particle friction coefficient decreases with the increasing load, which is contrary to the behavior of macroscopic contacting bodies. The measured friction coefficient is then introduced into the model proposed by Lobry et al to predict the viscosity of suspensions made by these polystyrene particles. The good agreement between the measured viscosity using a Rhometer and Lobry's predictions shows that the microscopic friction law governs the macroscopic viscosity of the suspensions
Soft interfaces : from elastocapillary snap-through to droplet dynamics on elastomers by Aurélie Hourlier-Fargette( )

1 edition published in 2017 in English and held by 1 WorldCat member library worldwide

Dans cette thèse à l'interface entre élasticité et capillarité, nous présentons tout d'abord une instabilité élastique, le claquage, revisitée dans un contexte élastocapillaire. En déposant une goutte d'eau sous une lamelle flambée en position basse, nous parvenons à déclencher une instabilité de claquage à contresens de la gravité. Cette démonstration de la prédominance des effets capillaires à petite échelle s'accompagne d'une étude des positions d'équilibre et de la stabilité de systèmes goutte-lamelle. Nous démontrons l'influence importante de la taille et de la position de la goutte le long de la lamelle, puis étendons notre étude au cas de bulles ou de gouttes condensées à partir de vapeur d'eau. Enfin, nous nous intéressons à l'aspect dynamique de l'instabilité, qui est dictée principalement par l'élasticité, y compris dans le cas élastocapillaire.Nous mettons ensuite en évidence un phénomène surprenant : la dynamique de descente d'une goutte d'eau sur un élastomère silicone présente deux régimes successifs, caractérisés par deux vitesses différentes. Nous montrons que les chaînes libres non réticulées présentes dans l'élastomère sont à l'origine de cette dynamique inattendue. La goutte est progressivement recouverte par des chaînes de silicone, et sa vitesse change brutalement lorsqu'une concentration surfacique critique est atteinte, ce qui se traduit par une transition brutale de tension de surface. Nous nous intéressons aux vitesses de gouttes dans les deux régimes ainsi qu'aux échelles de temps mises en jeu lors de l'extraction de chaînes non réticulées, et montrons que l'extraction de ces chaînes se produit au niveau de la ligne triple
 
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Elise Lorenceau onderzoeker

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French (17)

English (6)