Download or read book Optimized Amplification of Interface Distortion on Liquid Jets written by Hanul Hwang and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A fragmentation process of the liquid jet begins with the amplification of small disturbances. Understanding the evolution of the initial perturbation is critical in controlling the quality of the atomization outcomes, such as the droplet size distribution and the evaporation rate of the liquid, as these are directly related to the performance of a variety of atomization applications. In this study, we identify a novel mechanism for the effective amplification of the initial perturbation on liquid jets. This mechanism is independent of the exponential instability of the flow and can intensify small perturbations to the material interface by several orders of magnitude. Depending on its operating conditions, the liquid jet can amplify interfacial disturbances at a faster pace than can modal mechanisms such as the Kelvin--Helmholtz (K--H) instability. This study is based on a spatial linear stability theory in a two-fluid formulation that accounts for both viscosity and surface tension effects. The identified mechanism is verified using nonlinear simulations. In simulations, we observe nonlinear effects that create small-scale structures, a result not predicted in linear theory. As a measure of effective atomization, the small-scale structures are quantified by computing the surface area of the liquid jet. A study comparing the surface area between the liquid jet perturbed by the identified mechanism and the random inlet perturbation results higher surface area, which indicates that the identified mechanism drives more severe corrugation on the material interface leading to an effective atomization. A systematic framework for stability analysis of two-phase flows is constructed. The base flow of liquid jets is assumed to be streamwise invariant, stationary in time, axisymmetric, and laminar. Because of these assumptions, the base flow remains as the only function of radial direction. The ansatzes for the disturbance on a liquid jet are exponential functions in corresponding homogeneous directions. For an inhomogeneous direction, i.e., radial direction, disturbances are discretized using the Chebyshev spectral method. With linearized Navier-Stokes equations, the base flow, kinematic/dynamic interface conditions, and boundary conditions, analyzing the stability of liquid jets boils down to a well-posed eigenvalue problem. The eigenvalue problem is solved in the spatial framework where the input is a real perturbation frequency, and the outcomes are complex wavenumbers with corresponding eigenfunctions. A computationally cost-effective method is proposed to evaluate of eigenmode propagation direction. Unlike the temporal eigenvalue problem, solving the spatial eigenvalue problem adds more complexity in that the propagation direction of eigenmodes must be identified. Here, we solve the adjoint eigenvalue problem and invoke bi-orthogonality of the eigenfunctions to evaluate the group velocity of each eigenmode. With this group velocity evaluation metric, downstream propagating modes are identified. The effect of vorticity layer thickness on the downstream propagating unstable mode of liquid jets is explored. In addition, the identification of eigenmodes is illustrated using energy budgets. In contrast to classical modal growth analysis, a new pathway leading to an effective surface distortion of liquid jets is studied in detail. Analysis of the new mechanism is cast as an optimization problem that maximizes surface tension energy gain from the inlet perturbation distribution at the nozzle and discounts the trivial redistribution of perturbation kinetic energy. The identified mechanism is related to the Orr mechanism, and it amplifies distortions to the material interface via a reorientation of perturbations by the mean shear. Analyses of the linearized energy budgets show that energy is extracted from the mean shear by the production term of the streamwise perturbation velocity component and subsequently is transferred to the radial perturbation velocity component, where it is absorbed by the surface-tension potential of the interface. The gain in surface tension energy attributable to the mechanism is shown to scale linearly with the Reynolds number. A critical Weber number is identified as a lower bound beyond which the mechanism becomes active, and a power-law relation to the Reynolds number is established. The realizability of the identified mechanism is verified using nonlinear simulations. Numerical simulations of the optimized jets are conducted with a weakly compressible multiphase solver on an unstructured grid with algebraic VoF as an interface-tracking algorithm. We demonstrate the multiphase Orr mechanism as a realizable process for liquid jet atomization with various flow conditions. The comparison study of liquid jet surface area between the randomly disturbed jet and the optimized jet demonstrates the formation of the small-scale structures, and hence the ligaments, occurring within a relatively short downstream distance in the latter case.
Download or read book Zonal Jets written by Boris Galperin and published by Cambridge University Press. This book was released on 2019-02-28 with total page 527 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents a comprehensive, multidisciplinary volume on the physics of zonal jets, from the leading experts, for graduate students and researchers.
Download or read book Jet Cutting Technology written by A. Lichtarowicz and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 621 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains papers presented at the 11th International Conference on Jet Cutting Technology, held at St. Andrews, Scotland, on 8-10 September 1992. Jetting techniques have been successfully applied for many years in the field of cleaning and descaling. Today, however, jet cutting is used in operations as diverse as removing cancerous growths from the human body, decommissioning sunsea installations and disabling explosive munitions. The diversity is reflected in the papers presented at the conference. The papers were divided into several main sections: jetting basics -- materials; jetting basics -- fluid mechanics; mining and quarrying; civil engineering; new developments; petrochem; cleaning and surface treatment; and manufacturing. The high quality of papers presented at the conference has further reinforced its position as the premier event in the field. The volume will be of interest to researchers, developers and manufacturers of systems, equipment users and contractors.
Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1984 with total page 904 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Feedback Systems written by Karl Johan Åström and published by Princeton University Press. This book was released on 2021-02-02 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The essential introduction to the principles and applications of feedback systems—now fully revised and expanded This textbook covers the mathematics needed to model, analyze, and design feedback systems. Now more user-friendly than ever, this revised and expanded edition of Feedback Systems is a one-volume resource for students and researchers in mathematics and engineering. It has applications across a range of disciplines that utilize feedback in physical, biological, information, and economic systems. Karl Åström and Richard Murray use techniques from physics, computer science, and operations research to introduce control-oriented modeling. They begin with state space tools for analysis and design, including stability of solutions, Lyapunov functions, reachability, state feedback observability, and estimators. The matrix exponential plays a central role in the analysis of linear control systems, allowing a concise development of many of the key concepts for this class of models. Åström and Murray then develop and explain tools in the frequency domain, including transfer functions, Nyquist analysis, PID control, frequency domain design, and robustness. Features a new chapter on design principles and tools, illustrating the types of problems that can be solved using feedback Includes a new chapter on fundamental limits and new material on the Routh-Hurwitz criterion and root locus plots Provides exercises at the end of every chapter Comes with an electronic solutions manual An ideal textbook for undergraduate and graduate students Indispensable for researchers seeking a self-contained resource on control theory
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Engineering Design Optimization written by Joaquim R. R. A. Martins and published by Cambridge University Press. This book was released on 2021-11-18 with total page 653 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on course-tested material, this rigorous yet accessible graduate textbook covers both fundamental and advanced optimization theory and algorithms. It covers a wide range of numerical methods and topics, including both gradient-based and gradient-free algorithms, multidisciplinary design optimization, and uncertainty, with instruction on how to determine which algorithm should be used for a given application. It also provides an overview of models and how to prepare them for use with numerical optimization, including derivative computation. Over 400 high-quality visualizations and numerous examples facilitate understanding of the theory, and practical tips address common issues encountered in practical engineering design optimization and how to address them. Numerous end-of-chapter homework problems, progressing in difficulty, help put knowledge into practice. Accompanied online by a solutions manual for instructors and source code for problems, this is ideal for a one- or two-semester graduate course on optimization in aerospace, civil, mechanical, electrical, and chemical engineering departments.
Download or read book Physics and Chemistry of Interfaces written by Hans-Jürgen Butt and published by John Wiley & Sons. This book was released on 2023-02-07 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: Physics and Chemistry of Interfaces Comprehensive textbook on the interdisciplinary field of interface science, fully updated with new content on wetting, spectroscopy, and coatings Physics and Chemistry of Interfaces provides a comprehensive introduction to the field of surface and interface science, focusing on essential concepts rather than specific details, and on intuitive understanding rather than convoluted math. Numerous high-end applications from surface technology, biotechnology, and microelectronics are included to illustrate and help readers easily comprehend basic concepts. The new edition contains an increased number of problems with detailed, worked solutions, making it ideal as a self-study resource. In topic coverage, the highly qualified authors take a balanced approach, discussing advanced interface phenomena in detail while remaining comprehensible. Chapter summaries with the most important equations, facts, and phenomena are included to aid the reader in information retention. A few of the sample topics included in Physics and Chemistry of Interfaces are as follows: Liquid surfaces, covering microscopic picture of a liquid surface, surface tension, the equation of Young and Laplace, and curved liquid surfaces Thermodynamics of interfaces, covering surface excess, internal energy and Helmholtz energy, equilibrium conditions, and interfacial excess energies Charged interfaces and the electric double layer, covering planar surfaces, the Grahame equation, and limitations of the Poisson-Boltzmann theory Surface forces, covering Van der Waals forces between molecules, macroscopic calculations, the Derjaguin approximation, and disjoining pressure Physics and Chemistry of Interfaces is a complete reference on the subject, aimed at advanced students (and their instructors) in physics, material science, chemistry, and engineering. Researchers requiring background knowledge on surface and interface science will also benefit from the accessible yet in-depth coverage of the text.
Download or read book Aeroacoustics of Flight Vehicles written by Harvey H. Hubbard and published by . This book was released on 1991 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1972 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fox and McDonald s Introduction to Fluid Mechanics written by Robert W. Fox and published by John Wiley & Sons. This book was released on 2020-06-30 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: Through ten editions, Fox and McDonald's Introduction to Fluid Mechanics has helped students understand the physical concepts, basic principles, and analysis methods of fluid mechanics. This market-leading textbook provides a balanced, systematic approach to mastering critical concepts with the proven Fox-McDonald solution methodology. In-depth yet accessible chapters present governing equations, clearly state assumptions, and relate mathematical results to corresponding physical behavior. Emphasis is placed on the use of control volumes to support a practical, theoretically-inclusive problem-solving approach to the subject. Each comprehensive chapter includes numerous, easy-to-follow examples that illustrate good solution technique and explain challenging points. A broad range of carefully selected topics describe how to apply the governing equations to various problems, and explain physical concepts to enable students to model real-world fluid flow situations. Topics include flow measurement, dimensional analysis and similitude, flow in pipes, ducts, and open channels, fluid machinery, and more. To enhance student learning, the book incorporates numerous pedagogical features including chapter summaries and learning objectives, end-of-chapter problems, useful equations, and design and open-ended problems that encourage students to apply fluid mechanics principles to the design of devices and systems.
Download or read book Fundamentals of Multiphase Flow written by Christopher E. Brennen and published by Cambridge University Press. This book was released on 2005-04-18 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Publisher Description
Download or read book Handbook of Atomization and Sprays written by Nasser Ashgriz and published by Springer Science & Business Media. This book was released on 2011-02-18 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomization and sprays are used in a wide range of industries: mechanical, chemical, aerospace, and civil engineering; material science and metallurgy; food; pharmaceutical, forestry, environmental protection; medicine; agriculture; meteorology and others. Some specific applications are spray combustion in furnaces, gas turbines and rockets, spray drying and cooling, air conditioning, powdered metallurgy, spray painting and coating, inhalation therapy, and many others. The Handbook of Atomization and Sprays will bring together the fundamental and applied material from all fields into one comprehensive source. Subject areas included in the reference are droplets, theoretical models and numerical simulations, phase Doppler particle analysis, applications, devices and more.
Download or read book Applied Engineering Principles Manual Training Manual NAVSEA written by Naval Sea Systems Command and published by . This book was released on 2019-07-15 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 1 ELECTRICAL REVIEW 1.1 Fundamentals Of Electricity 1.2 Alternating Current Theory 1.3 Three-Phase Systems And Transformers 1.4 Generators 1.5 Motors 1.6 Motor Controllers 1.7 Electrical Safety 1.8 Storage Batteries 1.9 Electrical Measuring Instruments Chapter 2 ELECTRONICS REVIEW 2.1 Solid State Devices 2.2 Magnetic Amplifiers 2.3 Thermocouples 2.4 Resistance Thermometry 2.5 Nuclear Radiation Detectors 2.6 Nuclear Instrumentation Circuits 2.7 Differential Transformers 2.8 D-C Power Supplies 2.9 Digital Integrated Circuit Devices 2.10 Microprocessor-Based Computer Systems Chapter 3 REACTOR THEORY REVIEW 3.1 Basics 3.2 Stability Of The Nucleus 3.3 Reactions 3.4 Fission 3.5 Nuclear Reaction Cross Sections 3.6 Neutron Slowing Down 3.7 Thermal Equilibrium 3.8 Neutron Density, Flux, Reaction Rates, And Power 3.9 Slowing Down, Diffusion, And Migration Lengths 3.10 Neutron Life Cycle And The Six-Factor Formula 3.11 Buckling, Leakage, And Flux Shapes 3.12 Multiplication Factor 3.13 Temperature Coefficient...
Download or read book Aeronautical Engineering written by and published by . This book was released on 1992 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).
Download or read book Stability and Transition in Shear Flows written by Peter J. Schmid and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: A detailed look at some of the more modern issues of hydrodynamic stability, including transient growth, eigenvalue spectra, secondary instability. It presents analytical results and numerical simulations, linear and selected nonlinear stability methods. By including classical results as well as recent developments in the field of hydrodynamic stability and transition, the book can be used as a textbook for an introductory, graduate-level course in stability theory or for a special-topics fluids course. It is equally of value as a reference for researchers in the field of hydrodynamic stability theory or with an interest in recent developments in fluid dynamics. Stability theory has seen a rapid development over the past decade, this book includes such new developments as direct numerical simulations of transition to turbulence and linear analysis based on the initial-value problem.
Download or read book Computational Aerodynamics written by Antony Jameson and published by Cambridge University Press. This book was released on 2022-09 with total page 627 pages. Available in PDF, EPUB and Kindle. Book excerpt: Learn the design and analysis of numerical algorithms for aerodynamics. Ideal for graduates, researchers, and professionals in the field.
