Download or read book Nonlinear and Non modal Stability of Structures Evolving in Shear Flows written by Conor Anthony Daly and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 2000-12-28 with total page 578 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 Physics of Transitional Shear Flows written by Andrey V. Boiko and published by Springer Science & Business Media. This book was released on 2011-09-15 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Starting from fundamentals of classical stability theory, an overview is given of the transition phenomena in subsonic, wall-bounded shear flows. At first, the consideration focuses on elementary small-amplitude velocity perturbations of laminar shear layers, i.e. instability waves, in the simplest canonical configurations of a plane channel flow and a flat-plate boundary layer. Then the linear stability problem is expanded to include the effects of pressure gradients, flow curvature, boundary-layer separation, wall compliance, etc. related to applications. Beyond the amplification of instability waves is the non-modal growth of local stationary and non-stationary shear flow perturbations which are discussed as well. The volume continues with the key aspect of the transition process, that is, receptivity of convectively unstable shear layers to external perturbations, summarizing main paths of the excitation of laminar flow disturbances. The remainder of the book addresses the instability phenomena found at late stages of transition. These include secondary instabilities and nonlinear features of boundary-layer perturbations that lead to the final breakdown to turbulence. Thus, the reader is provided with a step-by-step approach that covers the milestones and recent advances in the laminar-turbulent transition. Special aspects of instability and transition are discussed through the book and are intended for research scientists, while the main target of the book is the student in the fundamentals of fluid mechanics. Computational guides, recommended exercises, and PowerPoint multimedia notes based on results of real scientific experiments supplement the monograph. These are especially helpful for the neophyte to obtain a solid foundation in hydrodynamic stability. To access the supplementary material go to extras.springer.com and type in the ISBN for this volume.
Download or read book Handbook of Mathematical Fluid Dynamics written by S. Friedlander and published by Gulf Professional Publishing. This book was released on 2003-03-27 with total page 627 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Handbook of Mathematical Fluid Dynamics is a compendium of essays that provides a survey of the major topics in the subject. Each article traces developments, surveys the results of the past decade, discusses the current state of knowledge and presents major future directions and open problems. Extensive bibliographic material is provided. The book is intended to be useful both to experts in the field and to mathematicians and other scientists who wish to learn about or begin research in mathematical fluid dynamics. The Handbook illuminates an exciting subject that involves rigorous mathematical theory applied to an important physical problem, namely the motion of fluids.
Download or read book Nonmodal Analysis of Temporal Transverse Shear Instabilities in Shallow Flows written by Yarzar Tun and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Shallow flows are those whose width is significantly larger than their depth. In these types of flows, two dimensional coherent structures can be generated and can influence the flow greatly by the lateral transfer of mass and momentum. The development of coherent structures as a result of flow instabilities has been a topic of interest for environmental fluid mechanics for decades. Studies on the use of linear modal stability analysis is commonly found in literature. However, the relatively recent development in the field of hydrodynamic stability suggests that the traditional linear modal stability analysis does not describe the behaviour of the perturbations in finite time. The discrepancy between asymptotic behaviour and finite time behaviour is particularly large in shear driven flows and it is most likely to be the case for shallow flows. This study aims to provide a better understanding of finite time growth of perturbation energy in shallow flows. The three cases of shallow flows evaluated are the mixing layer, jet and wake. The critical cases are obtained through the linear modal analysis and nonmodal analysis was conducted to show the transient behaviour in finite time for what is so-called marginally stable. Finally, the thesis concludes by generalizing the finite time energy growth in the S-k space.
Download or read book The Nonlinear Evolution of Modes on Unstable Stratified Shear Layers written by Institute for Computer Applications in Science and Engineering and published by . This book was released on 1993 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Intermittency in Transitional Shear Flows written by Yohann Duguet and published by MDPI. This book was released on 2021-08-31 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains original peer-reviewed articles written by some of the most prominent international physicists active in the field of hydrodynamics. The topic is entirely devoted to the study of the transitional regimes of incompressible viscous flow found at the onset of turbulent flows. Nine articles written for this 2020 Special Issue of the journal Entropy (MDPI) have been gathered at the crossroads of fluid mechanics, statistical physics, complexity theory, and applied mathematics. They include experimental, analytic, and computational material of an academic level that has not been published anywhere else.
Download or read book An Energy Method Stability Model for Large Scale Structures in Turbulent Shear Flows written by Andrew C. Poje and published by . This book was released on 1993 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stability and Nonlinear Waves in Stratified Shear Flows written by David J. Benney and published by . This book was released on 1974* with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulence and Structures written by Herman Branover and published by Academic Press. This book was released on 1999 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence is one of the most wide-spread phenomena in the universe. It relates to processes within the atmosphere, ocean, deep within the earth, as well as to the stars. The general public usually knows about turbulence from the unpleasant shaking of an airplane, or from disastrous atmospheric phenomena such as typhoons and hurricanes. The chaotic and unpredictable behavior of turbulent movement makes it very difficult to study. The degree of understanding of turbulence is still far from being complete. Some progress was made with the recent advent of a new science--chaos theory. The authors succeeded in examining one basic feature of turbulence called helicity (or spirality) which is the foundation of explaining and predicting the generation of large turbulent structures (e.g. typhoons). Helicity is a universal feature existing not only in fluid flows but also in solid bodies and even in living organisms. This book can be especially useful for researchers and students in fluid mechanics, plasma, geophysics, biology, and meteorology. * Examines the helical mechanism of self-organization in nature and laboratory * Presents a unified approach to chaos and theory * Discusses similarities and differences in the formation of dynamic and magnetic structures * Successfully combines profound theoretical and experimental knowledge * Includes a disk with an expanded bibliographical database
Download or read book Structure of Turbulence and Drag Reduction written by Albert Gyr and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 617 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1976 a similar titled IUTAM Symposium (Structure of Turbulence and Drag Reduction) was held in Washington . However, the progress made during the last thirteen years as weil as the much promising current research desired a second one this year. In Washington drag reduction by additives and by direct manipulation of the walls (compliant walls and heated surfaces) were discussed. In the meantime it became evident that drag reduction also occurs when turbulence is influenced by geometrical means, e.g. by influencing the pressure distribution by the shape of the body (airfoils) or by the introduction of streamwise perturbances on a body (riblets). In the recent years turbulence research has seen increasing attention being focused on the investigation of coherent structures, mainly in Newtonian fluids. We all know that these structures are a significant feature of turbulent flows, playing an important role in the energy balance in such flows. However their place in turbulence theories as weil as the factors influencing their development are still poorly understood. Consequently, the investigation of phenomena in which the properties of coherent structures are alte red provides a promising means of improving our understanding of turbulent flows in general.
Download or read book Transition and Turbulence Control written by Mohamed Gad-el-Hak and published by World Scientific. This book was released on 2006 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains articles based on lectures given at the Workshop on Transition and Turbulence Control, hosted by the Institute for Mathematical Sciences, National University of Singapore, 8-10 December 2004. The lecturers included 13 of the world's foremost experts in the control of transitioning and turbulent flows. The chapters cover a wide range of subjects in the broad area of flow control, and will be useful to researchers working in this area in academia, government laboratories and industry. The coverage includes control theory, passive, active and reactive methods for controlling transitional and turbulent wall-bounded flows, noise suppression and mixing enhancement of supersonic turbulent jets, compliant coatings, modern flow diagnostic systems, and swept wing instabilities.
Download or read book Instability of Newtonian and Non Newtonian Free Shear Flows written by Jalel Azaiez and published by . This book was released on 1993 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Role of Stable Eigenmodes in Shear flow Instability Saturation and Turbulence written by Adrian Everett Fraser and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A flow in which two fluids slide by one another or two layers of a single fluid flow at different speeds is called a shear flow. These flows are of interest in a broad range of physical systems, including atmospheric and astrophysical ones. Their potential to be unstable, with small perturbations growing by feeding off the flow's kinetic energy, motivates their study. Particularly in astrophysical systems, these instabilities often drive turbulence that dramatically modifies the rate at which heat, particles, and momentum are transported across the flow. This thesis studies the nature of these instabilities and the ensuing turbulence, investigating the canonical shear-flow instability, the Kelvin-Helmholtz (KH) instability, in three systems. Specifically, large-scale stable modes are explored, which transfer energy from perturbations back to the shear flow and tend to decay in time, in contrast to unstable modes which take energy away from the flow and tend to grow. In systems where stable modes were investigated prior to this work, the same nonlinear interactions that transfer energy from large to small scales were shown to transfer energy from unstable to stable modes. Thus, they can potentially reach significant amplitudes despite their tendency to decay in the absence of nonlinear interactions. At large amplitudes, the energy sink they present can significantly modify the turbulent state, and accounting for them can significantly improve reduced models of turbulent transport. These prior studies all concerned plasma micro-instabilities or systems that were otherwise quasi-homogeneous. The KH instability is importantly macroscopic and inhomogeneous. Thus, this thesis presents a significant expansion to the set of systems in which stable modes have been investigated. Three studies are described in this thesis. Each study concerns a different flow configuration and a different set of physical effects: a piecewise-linear, fixed shear layer in hydrodynamics, a reinforced, sinusoidal shear flow in gyrokinetics, and a smooth, freely-evolving shear layer in MHD. It is shown that stable modes are nonlinearly coupled to unstable modes in each system. When stable modes are not suppressed by added physical effects, the transfer of energy from unstable to stable modes plays an important role in saturation, and stable modes are expected or directly shown to be excited to significant amplitudes in the ensuing turbulence. The excitation of stable modes is linked to the transport of momentum against its gradient, an effect previously observed in experiments. It is shown that accounting for stable modes can significantly improve reduced models of momentum transport in regimes where they reach significant amplitude. The major contributions of this work are twofold. First, nonlinear coupling to large-scale stable modes is shown to be a generic feature of KH-unstable shear flows. Stable modes are shown to provide a valuable interpretive framework for explaining how features of the turbulence change with system parameters (e.g.~understanding why adding a magnetic field in the direction of the shear flow enhances small-scale fluctuations), and they inform improvements to reduced models. Second, in carrying out this work, tools developed for studying stable modes in quasi-homogeneous systems have been extended to apply to inhomogeneous systems, with stable modes shown to be relevant in inhomogeneous systems for the first time. Thus, this work motivates investigations into stable modes more broadly in inhomogeneous systems and provides the necessary tools for these investigations. Further details of each study are given in the abstracts of Chapters 2, 3, and 4.
Download or read book Global Stability Analysis of Shear Flows written by Rameshkumar Bhoraniya and published by Springer. This book was released on 2023-03-11 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the fundamentals and advanced research on the global stability analysis of the shear flows. The contents investigate the results of global stability analysis for different configurations of internal and external shear flows. The topics covered are global stability analysis of converging-diverging channel flows, axisymmetric boundary layer developed on a circular cylinder, cone and inclined flat-plate boundary layer, and wall jets. It further explains the effect of divergence, convergence, transverse curvature, and pressure gradients on the global stability of the different configurations of shear flows. The book is a valuable reference for beginners, researchers, and professionals working in the field of aerodynamics and marine hydrodynamics.
Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Large Scale Structure in Turbulent Free Shear Flows written by J. T. C. Liu and published by . This book was released on 1977 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The existence of organized structures in turbulent shear flow has been the subject of recent observational discoveries in both the laboratory and in the atmosphere and ocean. The resent work on modeling such structures in a temporally developing, horizontally homogeneous turbulent free shear layer has been extended to the spatially developing mixing layer, there being no available rational transformation between the two nonlinear problems. The basis for the consideration is the kinetic energy development of the mean flow, large-scale structure and fine-grained turbulence with a conditional average, supplementing the usual time average, to separate the nonrandom from the random part of the fluctuations. The integrated form of the energy equations and the accompanying shape assumptions, is used to derive amplitude equations for the mean flow, characterized by the shear layer thickness, the nonrandom and random components of flow which are characterized by their respective energy densities. In general, the large-scale structure augments the spreading of the shear layer and enhances the fine-grained turbulence by taking energy from the mean flow and transferring it to the turbulence as it amplifies and subsequently decays. The maximal amplitude of the large-scale structure is attained by the initially most amplified mode, however, the relative enhancement of the fine-grained turbulence is achieved by both the magnitude of the large-scale structure and its streamwise lifetime. Thus a greater enhancement of the turbulence is achievable by the lower frequency mdoes which have longer streamwise lifetimes. The large-scale structure can also be controlled by increasing the initial level of turbulence, which would render its decay more rapidly. (Author).
