Download or read book Numerical Simulation of Droplets with Dynamic Contact Angles written by and published by . This book was released on 2014 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Droplet Dynamics Under Extreme Ambient Conditions written by Kathrin Schulte and published by Springer Nature. This book was released on 2022 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book presents the main results of the Collaborative Research Center SFB-TRR 75, which spanned the period from 2010 to 2022. Scientists from a variety of disciplines, ranging from thermodynamics, fluid mechanics, and electrical engineering to chemistry, mathematics, computer science, and visualization, worked together toward the overarching goal of SFB-TRR 75, to gain a deep physical understanding of fundamental droplet processes, especially those that occur under extreme ambient conditions. These are, for example, near critical thermodynamic conditions, processes at very low temperatures, under the influence of strong electric fields, or in situations with extreme gradients of boundary conditions. The fundamental understanding is a prerequisite for the prediction and optimisation of engineering systems with droplets and sprays, as well as for the prediction of droplet-related phenomena in nature. The book includes results from experimental investigations as well as new analytical and numerical descriptions on different spatial and temporal scales. The contents of the book have been organised according to methodological fundamentals, phenomena associated with free single drops, drop clusters and sprays, and drop and spray phenomena involving wall interactions.
Download or read book Direct Numerical Simulations of Gas Liquid Multiphase Flows written by Grétar Tryggvason and published by Cambridge University Press. This book was released on 2011-03-10 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurately predicting the behaviour of multiphase flows is a problem of immense industrial and scientific interest. Modern computers can now study the dynamics in great detail and these simulations yield unprecedented insight. This book provides a comprehensive introduction to direct numerical simulations of multiphase flows for researchers and graduate students. After a brief overview of the context and history the authors review the governing equations. A particular emphasis is placed on the 'one-fluid' formulation where a single set of equations is used to describe the entire flow field and interface terms are included as singularity distributions. Several applications are discussed, showing how direct numerical simulations have helped researchers advance both our understanding and our ability to make predictions. The final chapter gives an overview of recent studies of flows with relatively complex physics, such as mass transfer and chemical reactions, solidification and boiling, and includes extensive references to current work.
Download or read book Capillary Flows with Forming Interfaces written by Yulii D. Shikhmurzaev and published by CRC Press. This book was released on 2007-09-14 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: Capillary Flows with Forming Interfaces explores numerous theoretical problems that arise in the mathematical description of capillary flows. It focuses on developing a unified approach to a variety of seemingly very different capillary flows of practical importance where classical fluid mechanics leads to nonphysical results. The book begin
Download or read book Numerical Simulation of the Droplet surface Impact Using InterFoam written by Fei Gao and published by . This book was released on 2015 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: Droplet dynamics involves multi-scale forces from inertia body force, interior viscous shear stress to surface tension. The main purpose of this thesis is to simulate the normal impact of a liquid droplet on a hydrophobic surface by solving for the Navier-Stokes equations. The numerical results obtained is used to evaluate the effects of variable parameters on the droplet deformation evolution. The numerical simulation also works as a complimentary part of the experimental exploration, by the group members in the Droplet-Surface Impact Project in Northeastern University. The computational tool used is OpenFOAM, an open source CFD software package licensed and distributed by the OpenFOAM Foundation. The specific solver used is interFoam for this two phase problem. Water is modeled as a representative of the Newtonian fluids, while blood is modeled to represent non-Newtonian fluids. Multiple variables of the droplet-surface impact are investigated numerically: initial velocity, droplet diameter, transport properties, all of which contributes to a variation of the Weber number. The numerical results obtained for water droplets are supported by experimental data and also semi-empirical correlations. The spreading behavior and generation of ripples are in good agreement with that observed in the experimental tests. As the capillary effects become more dominant in the recoiling period, a discrepancy starts to show by a pre-maturely generated secondary droplet in simulation. Possible reasons are speculated for this discrepancy between numerical and experimental results. In the numerical comparison between water and blood droplets, a resemblance of droplet behavior in the initial spreading process is observed, while the recoiling process shows differences: blood droplets rebound in an "irregular" way compared to water droplets. The difference in deformation behaviors caused by varied transport properties leads to a way of distinguishing liquids by simple droplet-surface impact tests.
Download or read book Drop Surface Interactions written by Martin Rein and published by Springer Science & Business Media. This book was released on 2002-10-30 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a comprehensive overview of fluid mechanical, thermal and physico-chemical aspects of drop-surface interactions. Basic physical mechanisms pertaining to free-surface flow phenomena characteristic of drop impact on solid and liquid surfaces are explained emphasizing the importance of scaling. Moreover, physico-chemical fundamentals relating to a forced spreading of complex solutions, analytical tools for calculating compressibility effects, and heat transfer and phase change phenomena occurring during solidification and evaporation processes, respectively, are introduced in detail. Finally, numerical approaches particularly suited for modeling drop-surface interactions are consisely surveyed with a particular emphasis on boundary integral methods and Navier-Stokes algorithms (volume of fluid, level set and front tracking algorithms). The book is closed by contributions to a workshop on Drop-Surface Interactions held at the International Centre of Mechanical Sciences.
Download or read book Surface Science Techniques written by Gianangelo Bracco and published by Springer Science & Business Media. This book was released on 2013-01-11 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book describes the experimental techniques employed to study surfaces and interfaces. The emphasis is on the experimental method. Therefore all chapters start with an introduction of the scientific problem, the theory necessary to understand how the technique works and how to understand the results. Descriptions of real experimental setups, experimental results at different systems are given to show both the strength and the limits of the technique. In a final part the new developments and possible extensions of the techniques are presented. The included techniques provide microscopic as well as macroscopic information. They cover most of the techniques used in surface science.
Download or read book Numerical Investigation of Droplet Spread written by Sushrutha Reddy Gujjula and published by . This book was released on 2016 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present study of droplet spreading has many industrial applications of which, ink jet printing, plasma spraying, fire extinguishers are but a few. These applications need a detailed and fundamental understanding of the droplet spreading physics, which is divided into four phases. In the present work, two of these phases, namely, the spreading phase, and equilibrium phase have been analyzed. Since droplet spreading is a dynamic phenomenon where the surface of the droplet changes with time, capturing these changes requires a two-phase approach called volume of fluid (VOF) method. The VOF method uses an advection equation to determine the interface between the liquid and the surrounding air. At the intersection of this interface with a solid boundary is a point common to all three phases, solid, gas, and liquid. At the liquid-solid-gas contact point, contact-angle is the angle between the solid surface and the tangent to the liquid-gas interface, the contact-angle can also vary with time. A number of contact-angle models have been proposed and used in simulations of droplet spreading research reported in literature. The present study is a systematic analysis of the most widely used contact-angle models, which include both, static and dynamic contact-angle models, on surfaces with varying wettability, i.e. hydrophilic and hydrophobic surfaces. To compile the contact-angle models, an open source code, OpenFOAM was used. Results from simulations are presented and compared with those from experiments, conducted by Pasandideh Fard et al. [21] and Vadillo et al. [26]. In addition, two parameters, called the maximum spreading diameter, and the equilibrium spreading diameter, were also analyzed in detail. The results indicated that, using the static contact angle models over-predicted the maximum spreading diameter for the hydrophilic case, whereas the equilibrium spreading diameter was under-predicted. In case of the hydrophobic surface, the maximum spreading diameter was predicted well, but the equilibrium spreading diameter was slightly under-predicted. Simulations using the dynamically varying contact angles with respect to empirical correlations and theoretical expressions slightly under-predicted the overall trend of the spreading diameter. But observations of the maximum and equilibrium diameters were predicted better. Using the experimentally measured contact-angle values as a boundary condition in the simulations improved the dynamic spreading diameter prediction.
Download or read book Numerical Methods for Fluid Dynamics written by Institute of Mathematics and Its Applications and published by . This book was released on 1982 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Surface Wetting written by Kock-Yee Law and published by Springer. This book was released on 2015-11-18 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes wetting fundamentals and reviews the standard protocol for contact angle measurements. The authors include a brief overview of applications of contact angle measurements in surface science and engineering. They also discuss recent advances and research trends in wetting fundamentals and include measurement techniques and data interpretation of contract angles.
Download or read book High Performance Computing in Science and Engineering 21 written by Wolfgang E. Nagel and published by Springer Nature. This book was released on 2023-03-03 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the state-of-the-art in supercomputer simulation. It includes the latest findings from leading researchers using systems from the High Performance Computing Center Stuttgart (HLRS) in 2021. The reports cover all fields of computational science and engineering ranging from CFD to computational physics and from chemistry to computer science with a special emphasis on industrially relevant applications. Presenting findings of one of Europe’s leading systems, this volume covers a wide variety of applications that deliver a high level of sustained performance. The book covers the main methods in high-performance computing. Its outstanding results in achieving the best performance for production codes are of particular interest for both scientists and engineers. The book comes with a wealth of color illustrations and tables of results.
Download or read book Moving Particle Semi implicit Method written by Seiichi Koshizuka and published by Academic Press. This book was released on 2018-06-01 with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt: Moving Particle Semi-implicit Method: A Meshfree Particle Method for Fluid Dynamics begins by familiarizing the reader with basic theory that supports their journey through sections on advanced MPH methods. The unique insights that this method provides include fluid-structure interaction, non-Newtonian flow, and cavitation, making it relevant to a wide range of applications in the mechanical, structural, and nuclear industries, and in bioengineering. Co-authored by the originator of the MPS method, this book is the most authoritative guide available. It will be of great value to students, academics and researchers in industry. - Presents the differences between MPH and SPH, helping readers choose between methods for different purposes - Provides pieces of computer code that readers can use in their own simulations - Includes the full, extended algorithms - Explores the use of MPS in a range of industries and applications, including practical advice
Download or read book Applying Dynamic Contact Angles to a Three dimensional VOF Model written by Shahriar Afkhami Zakerzadeh and published by . This book was released on 2007 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a three-dimensional numerical model to simulate the dynamic behaviour of moving contact line phenomena. The model consists of an adaptive mesh discretization of the time-dependent Navier-Stokes equations for incompressible two-phase flows with a volume-of-fluid technique for interface tracking. Surface tension is modelled as a volume force acting on the interface. The height function methodology is utilized to accurately estimate the normals and the curvatures at the fluid/fluid interface and at the contact line. Contact angles are imposed as a boundary condition at the contact line. An early version of "GERRIS", which is based on an adaptive mesh method for the incompressible Euler equations, was used as the basis for the development of the numerical method. Algorithms for evaluating surface tension and variable-viscosity shear stresses were incorporated into the code. The code was then used as the basis for developing the contact line methodology presented in this thesis. In particular; (i) a two- and three-dimensional height function-based approach is developed to apply a specified contact angle, and (ii) based on an analytical model, a velocity and mesh-dependent contact angle model is developed to properly apply dynamic contact angles. Equilibrium results of two- and three-dimensional droplets with various contact angles are presented first. Simulation results are compared with known solutions and the convergence behaviour of the model is studied. The model is then used for the development of a numerical methodology for the simulation of dynamic wetting/dewetting lines. The goal is to investigate the effect of the contact angle boundary condition on the dynamics of spreading. Key factors, mechanisms by which the contact line motion occurs, are investigated. These mechanisms include: the slip of a moving contact line on the solid surface and the dynamic behaviour of the contact angle. A dynamic contact angle model is then presented that leads to results that converge with spatial refinement. The thesis concludes with the model applied to small sliding droplets on a partially wetting surface. Results are presented of sliding droplets on an inclined plane with dynamic contact angles. The effect of the inclination angle on the distribution of the contact angle along the droplet perimeter is presented.
Download or read book Microdroplet Technology written by Philip Day and published by Springer Science & Business Media. This book was released on 2012-07-28 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microdroplet technology has recently emerged to provide new and diverse applications via microfluidic functionality, especially in various areas of biology and chemistry. This book, then, gives an overview of the principle components and wide-ranging applications for state-of-the-art of droplet-based microfluidics. Chapter authors are internationally-leading researchers from chemistry, biology, physics and engineering that present various key aspects of micrdroplet technology -- fundamental flow physics, methodology and components for flow control, applications in biology and chemistry, and a discussion of future perspectives. This book acts as a reference for academics, post-graduate students, and researcher wishing to deepen their understand of microfluidics and introduce optimal design and operation of new droplet-based microfluidic devices for more comprehensive analyte assessments.
Download or read book Dynamics of Droplets written by Arnold Frohn and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book deals with the dynamical behaviour of single droplets and regular droplet systems. It has been written mainly for experimental researchers. After a short description of the theoretical background, the different experimental facilities and methods necessary for the investigation of single droplets are described in detail. A summary of important applications is included.
Download or read book Handbook of Numerical Simulation of In Flight Icing written by Wagdi George Habashi and published by Springer Nature. This book was released on 2024-01-12 with total page 1278 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Handbook of Numerical Simulation of In-Flight Icing covers an array of methodologies and technologies on numerical simulation of in-flight icing and its applications. Comprised of contributions from internationally recognized experts from the Americas, Asia, and the EU, this authoritative, self-contained reference includes best practices and specification data spanning the gamut of simulation tools available internationally that can be used to speed up the certification of aircraft and make them safer to fly into known icing. The collection features nine sections concentrating on aircraft, rotorcraft, jet engines, UAVs; ice protection systems, including hot-air, electrothermal, and others; sensors and probes, CFD in the aid of testing, flight simulators, and certification process acceleration methods. Incorporating perspectives from academia, commercial, government R&D, the book is ideal for a range of engineers and scientists concerned with in-flight icing applications.
Download or read book Particles at Fluid Interfaces written by Erica Wanless and published by Frontiers Media SA. This book was released on 2019-05-09 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particles at Fluid Interfaces encompasses the processes and formulations that involve the stabilisation of fluid interfaces by adsorbed particles. The prevalence of these multiphase materials underpins their use in a broad range of industries from personal care and food technology to oil and mineral processing. The stabilisation conferred by the adsorbed particles can be transient as found in froth flotation or long-lived as occurs within Pickering Emulsions. The particles can range in size from nanoparticles to millimetre-sized particles, and cover a spectrum from collapsed proteins, polymeric colloids of controlled size and shape to high dispersity mineral particles.
