Download or read book Dynamic Evolution of Thin Liquid Films Over Curved Substrates written by Xingyi Shi and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We encounter thin liquid films on a daily basis. The micron-thick tear film coating the cornea ensures the clarity of our vision. Pulmonary surfactants coating the air-liquid interface in the alveoli enable us to breath. Lubricant foaming in a gear box can lead to machine degradation and unsafe operations. Textile dye solution films drying unevenly can leave undesirable marks on the fabric. A fundamental understanding of thin liquid film stability is key to optimizing the compositions of the base liquid to suit our needs and applications. In this research, we examine the effects of liquid composition and substrate materials on the dynamics of thin liquid films by building heat and mass transfer models and conducting interferometric experiments via the dynamic fluid-film interferometer. The geometry of a thin liquid film dictates that the liquid-air interactions are critical in affecting the dynamics of the films. Many such interactions can lead to an uneven distribution of surface tension, creating Marangoni flow. The interplay between the Marangoni flow and other physical forces such as capillarity and gravity govern the dynamics of most thin liquid films. A key part of the work focuses on one of the simplest systems that captures all of the major physical forces at play in a thin liquid film: evaporating binary silicone oil films over a glass dome or an air bubble. The binary silicone oil composes of two silicone oils with different viscosity, surface tension, and evaporation rate. Evaporation and the curvature of the substrates create a thin film with varying thickness and composition, thereby surface tension. In the experimental system, a thin film is formed by forcing the curved substrate upward until the apex of the substrate penetrates the initially flat air/liquid interface. The forcing is then stopped and the evolution of the film is recorded by a camera positioned directly above the thin film. Combining experimental observations and theoretical modeling, we elucidate the mechanisms behind the resulting dramatic thin film dynamics. For a binary silicone oil film over a glass dome, at low volume fractions of the less evaporative species ( 0.3%), the liquid film remains axisymmetric and is stabilized by van der Waals interactions and Marangoni flows [1]. At higher concentrations ( 0.35%), the increase in Marangoni flow leads to a film that is more susceptible to ambient disturbances, resulting in asymmetry breakage events [2]. Faster dynamics are observed for an oil film over an air bubble, due to the reduction in resistance to flow. At low volume fractions of the more evaporative species (

Download or read book Thin Liquid Films written by Ralf Blossey and published by Springer Science & Business Media. This book was released on 2012-05-22 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a treatise on the thermodynamic and dynamic properties of thin liquid films at solid surfaces and, in particular, their rupture instabilities. For the quantitative study of these phenomena, polymer thin films (sometimes referred to as “ultrathin”) have proven to be an invaluable experimental model system. What is it that makes thin film instabilities special and interesting? First, thin polymeric films have an important range of applications. An understanding of their instabilities is therefore of practical relevance for the design of such films. The first chapter of the book intends to give a snapshot of current applications, and an outlook on promising future ones. Second, thin liquid films are an interdisciplinary research topic, which leads to a fairly heterogeneous community working on the topic. It justifies attempting to write a text which gives a coherent presentation of the field which researchers across their specialized communities might be interested in. Finally, thin liquid films are an interesting laboratory for a theorist to confront a well-established theory, hydrodynamics, with its limits. Thin films are therefore a field in which a highly fruitful exchange and collaboration exists between experimentalists and theorists. The book stretches from the more concrete to more abstract levels of study: we roughly progress from applications via theory and experiment to rigorous mathematical theory. For an experimental scientist, the book should serve as a reference and guide to what is the current consensus of the theoretical underpinnings of the field of thin film dynamics. Controversial problems on which such a consensus has not yet been reached are clearly indicated in the text, as well as discussed in a final chapter. From a theoretical point of view, the field of dewetting has mainly been treated in a mathematically ‘light’ yet elegant fashion, often making use of scaling arguments. For the untrained researcher, this approach is not always easy to follow. The present book attempts to bridge between the ‘light’ and the ‘rigorous’, always with the ambition to enhance insight and understanding - and to not let go the elegance of the theory.

Download or read book Falling Liquid Films written by S. Kalliadasis and published by Springer Science & Business Media. This book was released on 2011-09-24 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: Falling Liquid Films gives a detailed review of state-of-the-art theoretical, analytical and numerical methodologies, for the analysis of dissipative wave dynamics and pattern formation on the surface of a film falling down a planar inclined substrate. This prototype is an open-flow hydrodynamic instability, that represents an excellent paradigm for the study of complexity in active nonlinear media with energy supply, dissipation and dispersion. It will also be of use for a more general understanding of specific events characterizing the transition to spatio-temporal chaos and weak/dissipative turbulence. Particular emphasis is given to low-dimensional approximations for such flows through a hierarchy of modeling approaches, including equations of the boundary-layer type, averaged formulations based on weighted residuals approaches and long-wave expansions. Whenever possible the link between theory and experiment is illustrated, and, as a further bridge between the two, the development of order-of-magnitude estimates and scaling arguments is used to facilitate the understanding of basic, underlying physics. This monograph will appeal to advanced graduate students in applied mathematics, science or engineering undertaking research on interfacial fluid mechanics or studying fluid mechanics as part of their program. It will also be of use to researchers working on both applied, fundamental theoretical and experimental aspects of thin film flows, as well as engineers and technologists dealing with processes involving isothermal or heated films. This monograph is largely self-contained and no background on interfacial fluid mechanics is assumed.

Download or read book Dynamics of Thin Liquid Films written by Vilhjalmur Ludviksson and published by . This book was released on 1968 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evolution of Thin Film Morphology written by Matthew Pelliccione and published by Springer Science & Business Media. This book was released on 2008-01-29 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus of this book is on modeling and simulations used in research on the morphological evolution during film growth. The authors emphasize the detailed mathematical formulation of the problem. The book will enable readers themselves to set up a computational program to investigate specific topics of interest in thin film deposition. It will benefit those working in any discipline that requires an understanding of thin film growth processes.

Download or read book Dynamics of Thin Liquid Films Over a Spinning Disk written by Kun Zhao and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Complex Wave Dynamics on Thin Films written by Hen-hong Chang and published by Elsevier. This book was released on 2002-03-14 with total page 413 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wave evolution on a falling film is a classical hydrodynamic instability whose rich wave dynamics have been carefully recorded in the last fifty years. Such waves are known to profoundly affect the mass and heat transfer of multi-phase industrial units. This book describes the collective effort of both authors and their students in constructing a comprehensive theory to describe the complex wave evolution from nearly harmonic waves at the inlet to complex spatio-temporal patterns involving solitary waves downstream. The mathematical theory represents a significant breakthrough from classical linear stability theories, which can only describe the inlet harmonic waves and also extends classical soliton theory for integrable systems to real solitrary wave dynamics with dissipation. One unique feature of falling-film solitary wave dynamics, which drives much of the spatio-temporal wave evolution, is the irreversible coalescence of such localized wave structures. It represents the first full description of a hydrodynamic instability from inception to developed chaos. This approach should prove useful for other complex hydrodynamic instabilities and would allow industrial engineers to better design their multi-phase apparati by exploiting the deciphered wave dynamics. This publication gives a comprehensive review of all experimental records and existing theories and significantly advances state of the art on the subject and are complimented by complex and attractive graphics from computational fluid mechanics.

Download or read book Thin Liquid Films written by Gary Francis Teletzke and published by . This book was released on 1983 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wetting and Spreading Dynamics Second Edition written by Victor M. Starov and published by CRC Press. This book was released on 2019-07-02 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wetting and Spreading Dynamics explains how surface forces acting at the three-phase contact line determine equilibrium, hysteresis contact angles, and other equilibrium and kinetics features of liquids when in contact with solids or with other immiscible liquids. It examines the interaction of surface forces, capillary forces, and properties of the transition zone between the bulk liquid and solid substrate. Significantly revised and updated, the Second Edition features new chapters that cover spreading of non-Newtonian liquids over porous substrates, hysteresis of contact angles on smooth homogeneous substrates, equilibrium and hysteresis contact angles on deformable substrates, and kinetics of simultaneous spreading and evaporation. Drawing together theory and experimental data while presenting over 150 figures to illustrate the concepts, Wetting and Spreading Dynamics, Second Edition is a valuable resource written for both newcomers and experienced researchers.

Download or read book The Dynamics of Thin Liquid Films written by Michael Paul Ida and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Dynamics of Thin Liquid Films written by and published by . This book was released on 2004 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stable Localized Patterns in Thin Liquid Films written by Robert J. Deissler and published by . This book was released on 1991 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Thin and Ultra thin Liquid Films on Dynamic Wetting written by Xia Chen and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thin Liquid Films written by Ivan Ivanov and published by CRC Press. This book was released on 1988-08-31 with total page 1152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin Liquid Films furnishes a fundamental overview of thermodynamics of thin liquid films. Generously illustrated with equations, tables and drawling and containing more than 2,200 citations to pertinent literature.

Download or read book Stability of Thin Liquid Films written by Antonio Iván Jiménez-Laguna and published by . This book was released on 1991 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book IUTAM Symposium on Nonlinear Waves in Multi Phase Flow written by H.-C. Chang and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: The active field of multi-phase flow has undergone fundamental changes in the last decade. Many salient complex interfacial dynamics of such flows are now understood at a basic level with precise mathematical and quantitative characterization. This is quite a departure from the traditional empirical approach. At an IUTAM Symposium at Notre Dame, in 1999, some of the leading researchers in the field gathered to review the progress thus far and to contemplate future directions. Their reports are summarized in this Proceedings. Topics covered include solitary wave dynamics on viscous film flows, sheet formation and drop entrainment in stratified flow, wetting and dewetting dynamics, self-similar drop formation dynamics, waves in bubbly and suspension flow, and bubble dynamics. It is a unique and essential reference for applied mathematicians, physicists, research engineers, and graduate students to keep abreast of the latest theoretical and numerical developments that promise to transform multi-phase flow research.

Download or read book Characteristics and Applications of Thin Liquid Films Flowing Down High Curvature Surfaces written by Abolfazl Sadeghpour and published by . This book was released on 2020 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin liquid films flowing down vertical fibers present a wealth of complex and interesting interfacial dynamics, including the formation of droplets and traveling wave patterns. Such dynamics is an important consideration in various applications, such as fiber coating and direct-contact heat and mass exchangers which take advantage of extended interfacial areas and larger residence time afforded by the bead formation along the fiber. A rigorous investigation on the fluid dynamics and interfacial heat and mass transfer mechanism of liquid films flowing along vertical strings is, thus, needed to enable physics-based optimization and analysis of multi-string designs for the mentioned applications. This dissertation presents a combination of experimental, numerical, and theoretical study of liquid films flowing down a vertical fiber. Additionally, we report a first-ever combined experimental and theoretical study of the instability in thin film flows of a high-surface energy low-viscosity liquid (i.e. water) along cotton threads. Utilizing our finding, we then adapted the multi-string configuration for novel applications, such as humidification, dehumidification, and particle capturing. We started with a thorough experimental study of viscous liquids flowing down vertical fibers (i.e. polymer strings). Previous researchers suggested that the liquid film thickness and velocity profiles of nearly flat portion of a liquid film that precedes the onset of instability can be specified regardless of the nozzle geometry. As a result, they largely overlooked the effects of nozzle on the pattern and characteristics of the downstream flow. We performed a systematic experimental study by varying the nozzle inner diameter from 0.5 to 3.2 mm at various mass flow rates (from 0.02 to 0.08 g/s). We focused on experimental conditions within the Rayleigh Plateau (RP) instability regime, where traveling wave solution emerges and generates uniformly-spaced drop-like liquid beads on vertical fibers. Our results emphasize the strong influence of nozzle geometry on the flow regime and the flow characteristics. We experimentally measured the thickness of the flat film portion after the nozzle, which we term the preinstability thickness, and identified it as a flow parameter which governs the size, spacing, and velocity of downstream liquid beads. We also performed a set of complementary numerical simulations that solves the full Navier-Stokes equations to predict the fluid dynamics of the downstream flow, such as the liquid velocity profile along the fiber. To better understand the influence of nozzle diameter on the regime transition as well as the downstream bead dynamics, we performed a detailed theoretical study of viscous flow down a vertical fiber. We proposed a full lubrication model that includes slip boundary conditions, nonlinear curvature terms, and a film stabilization term, and compared the predicted film dynamics against the experimental results. Numerical simulations confirm that in addition to fiber sizes and flow rates, the downstream flow regime and characteristics are also significantly affected by the nozzle geometry. Moreover, the effect of film stabilization term on the flow pattern and bead characteristic is studied. We also compared our results with previously studied theoretical methods, such as CM model, linear curvature model, and full curvature model. Additionally, we leveraged our successful demonstration of stable water flow along a vertical cotton string to construct a multi-string water vapor capturing system, where a massive array traveling water beads act as the condensation interface for water vapor in the counterflowing air stream. These water beads form through intrinsic flow instability and offer high curvature surfaces to enhance the vapor condensation rate. The effects of the water flow rate and air velocity on the condensation rates are experimentally characterized. The gas-stream pressure drop of the design is also measured. The condensation rates and gas-stream pressure drop from our multi-string dehumidifier is compared with the existing dehumidifier designs. A simplified theoretical model is also presented as the starting point for further optimizing the design parameters of our device. Finally, we extended our investigation for potential applications of the cotton-based multi-string configuration and proposed a novel string-based particle collector. Wet electrostatic precipitators (WESP) are generally highly effective for collecting fine particles in air streams from various sources such as diesel engines, power plants, and oil refineries. However, some limiting factors, such as high water usage, poses restrictions. Our new compact particle collector utilizes an array of traveling water beads on vertical cotton strings to collect the pre-charged particles in the counterflowing air stream. The experimental and numerical investigation presented in this work is performed to determine the collection efficiency and the optimal water flow rate for our new design. The unique configuration of our string-based counterflow WESP in this study exhibits high number-based collection efficiency, > 80%, for a wide range of particle diameters, 10 nm - 2.5 m, while decreasing the water usage significantly, which can provide a basis for the design of more water-efficient WESPs.