Author: Pierre Colinet Publisher: Springer Science & Business Media ISBN: 3709101255 Category : Technology & Engineering Languages : en Pages : 304
Book Description
The book deals with modern methods of nonlinear stability theory applied to problems of continuous media mechanics in the presence of interfaces, with applications to materials science, chemical engineering, heat transfer technologies, as well as in combustion and other reaction-diffusion systems. Interfaces play a dominant role at small scales, and their correct modeling is therefore also crucial in the rapidly expanding fields of microfluidics and nanotechnologies. To this aim, the book combines contributions of eminent specialists in the field, with a special emphasis on rigorous and predictive approaches. Other goals of this volume are to allow the reader to identify key problems of high scientific value, and to see the similarity between a variety of seemingly different physical problems.
Author: Eduardo Guzmán Publisher: MDPI ISBN: 3039436333 Category : Science Languages : en Pages : 232
Book Description
Fluid interfaces are promising candidates for confining different types of materials, e.g., polymers, surfactants, colloids, and even small molecules, to be used in designing new functional materials with reduced dimensionality. The development of such materials requires a deepening of the physicochemical bases underlying the formation of layers at fluid interfaces as well as on the characterization of their structures and properties. This is of particular importance because the constraints associated with the assembly of materials at the interface lead to the emergence of equilibrium and features of dynamics in the interfacial systems, which are far removed from those conventionally found in traditional materials. This Special Issue is devoted to studies on the fundamental and applied aspects of fluid interfaces, and attempts to provide a comprehensive perspective on the current status of the research field.
Author: Publisher: ISBN: Category : Languages : en Pages : 26
Book Description
Energy consumption in fabrication of materials for all applications is process dependent. Improvements in the ability to process materials are of great importance to the DOE mission. This project addresses basic science questions related to the processing of materials and is aimed at understanding growth of interfaces and evolution of patterns on interfaces, both macroscopic and microscopic. Three laboratory experiments are proposed: A study of the changes in patterns available to the growth of a macroscopic interface when that interface is grown over one of a variety of microscopic'' lattices; a study of reversible aggregation of colloidal particles in a mixed solvent, and of the interactions and relaxations of both solvent and suspended particles when thermodynamic conditions are changed for a liquid matrix with suspended particles or fibres; and, an investigation of the sedimentation of particles in a quasi-two-dimensional viscous fluid, with attention both to the dynamics of the flow and to the roughness of the resulting surface of settled particles.
Author: Jean-Pierre Delville Publisher: Nova Science Pub Incorporated ISBN: 9781606924310 Category : Technology & Engineering Languages : en Pages : 88
Book Description
The formation, deformation, and break-up of liquid interfaces are ubiquitous phenomena in nature. In the present book the authors discuss the deformation of a liquid interface produced by optical radiation forces. Usually, the bending of such an interface by the radiation pressure of a c.w. laser beam is weak. However, the effect can be enhanced significantly if one works with a near-critical phase-separated liquid mixture, whereby the surface tension becomes weak. The bending may in this way become as large as several tenths of micrometers, even with the use of only moderate laser power. This near-criticality is a key element in our experimental investigations as reviewed in the article. The effect is achieved by working with a micellar phase of microemulsions, at room temperature. The authors give a brief survey of the theory of electromagnetic forces on continuous matter, and survey earlier experiments in this area, such as the Ashkin-Dziedzic optical radiation force experiment on a water/air surface, the Zhang-Chang experiment on the laser-induced deformation of a micrometer-sized spherical water droplet, and the experiment of Sakai et al. measuring surface tensions of interfaces in a non-contact manner. Thereafter, the authors survey results they obtained in recent years by performing experiments on near-critical interfaces, such as interface bending in the linear regime, stationary large deformations of liquid interfaces, asymmetric pressure effects on interfaces under intense illumination, non-linear deformations, and laser-sustained liquid columns.
Author: Shutao Qiao Publisher: ISBN: Category : Languages : en Pages : 342
Book Description
This dissertation focuses on fluid-induced large deformation at interfaces where at least one material is soft, i.e. materials with low Young’s modulus and capable of large deformation. Soft materials are finding important applications in many emerging fields such as soft electronics, soft robotics, and bio-integrated devices. Most often, soft materials have to form interfaces with other materials where fluids may present. Such interfacial fluids may affect attachment in negative or positive ways but so far, theoretical studies are rare due to the difficulties associated with large deformation and elasto-capillary effects. Regarding the dynamics of fluid flow as a sequence of static equilibrium states, it becomes sufficient to analyze problems in the context of solid mechanics. This dissertation provides nonlinear solutions to such classes of problems through two examples – interfacial blisters and craters. When a soft membrane covers a flat surface, interfacial blisters inflated by increasing amount of interfacial fluids may cause detachment between the membrane and the substrate. I formulated a nonlinear membrane theory to characterize the bulging and bulging-induced delamination process of the soft membrane. Elasto-capillary effects are considered due to their significance at small-scales. Solutions for both rigid and soft substrates are obtained. For rigid substrates, a variety of boundary conditions is modeled. In the second example, the crater problem is inspired by emerging experimental evidence that enhanced adhesion has been measured when a soft material with surface craters is pressed against a rigid surface. I established a nonlinear elasticity framework to model suction forces generated by the loading and unloading process. Both ideal gas and incompressible fluids have been considered. This framework has been validated by experiments and has been applied to optimize the design of craters. The nonlinear theoretical frameworks established in this dissertation offer methodologies to model and understand other soft material interfaces with interfacial fluids
Author: Jia Zhang Publisher: ISBN: Category : Electrohydrodynamics Languages : en Pages : 82
Book Description
The interactions between an electric field and fluid motion give rise to a class of complex and important phenomena known as electrohydrodynamics. In this work, we developed a set of analytical tools to provide basic understanding and quantitative prediction capabilities. Under this theme, three tasks have been accomplished. 1. A general solution approach for the electrohydrodynamic instability of stratified immiscible fluids is presented. The problems of two and three fluid layers subject to normal electric fields are analyzed. Analytical solutions are obtained by employing the transfer relations relating the disturbance stresses to the flow variables at the interface(s). The results assume a general format. Both new dispersion relations and those from various previous work are shown to be special cases when proper simplifications are considered. As a specific example, the stability behavior of a three-layer channel flow is investigated in details using this framework. This work provides a unifying method to treat a generic class of instability problems. 2. A transient analysis to quantify droplet deformation under DC electric fields is presented. The full Taylor-Melcher leaky dielectric model is employed where the charge relaxation time is considered to be finite. The droplet is assumed to be spheroidal in shape for all times. The main result is an ODE governing the evolution of the droplet aspect ratio. The model is validated by extensively comparing predicted deformation with both previous theoretical and numerical studies, and with experimental data. Furthermore, the effects of parameters and stresses on deformation characteristics are systematically analyzed taking advantage of the explicit formulae on their contributions. The theoretical framework lays the foundation for the study of a more complex problem, vesicle electrodeformation. 3. A transient analysis for vesicle deformation under DC electric fields is developed. The theory extends from a droplet model, with the additional consideration of a lipid membrane separating two fluids of arbitrary properties. For the latter, both a membrane-charging and a membrane-mechanical model are supplied. The main result is also an ODE governing the evolution of the vesicle aspect ratio. The effects of initial membrane tension and pulse length are examined. The model prediction is extensively compared with experimental data, and is shown to accurately capture the system behavior in the regime of no or weak electroporation. More importantly, the comparison reveals that vesicle relaxation obeys a universal behavior regardless of the means of deformation. The process is governed by a single timescale that is a function of the vesicle initial radius, the fluid viscosity, and the initial membrane tension. This universal scaling law can be used to calculate membrane properties from experimental data. Together, these projects provide powerful tools to analyze a broad class of problems involving electrostatics, hydrodynamics, and membrane mechanics.
Author: Hans C. Mayer Publisher: ISBN: 9781339671147 Category : Languages : en Pages : 452
Book Description
In this work, several case studies involving complex short-time and small-scale behavior of fluid interfaces are presented. The case studies themselves are essentially unique -- involving various forces and effects (mechanical, chemical, electromagnetic, and thermal), and requiring different experimental techniques in order to elucidate the nature of the phenomena and to address the open questions. Some of the phenomena we explore are familiar to most individuals, for example spilling coffee while walking, the formation of a splash due to the impact of a solid object on a liquid surface, or the bursting of soap films. Others are not, like the behavior of coating flows, or the seemingly self-sustained behavior of micro-scale droplet formation using surfactant gradients. But all share intriguing questions, and interesting answers. This tour through a variety of interfacial phenomena has at its purpose, the goal of answering important open questions. The answers serve to verify existing theoretical predictions, resolve disputes between competing theories, and reveal the nature of previously reported behaviors.