Download or read book Instability and Turbulence in a Stratified Shear Layer written by Clinton Gary Koop and published by . This book was released on 1976 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of an experimental investigation of shear instability and turbulent mixing in a stratified fluid are presented. Two parallel streams of water, moving at different velocities and having different densities (salinities) are produced in an open channel. Dye and shadowgraph techniques are used to visualize the flow, and quantitative measurements of velocity and density are made with hot films and conductivity probes.
Download or read book Shear Layer and Jet Instability in Stratified Media written by George H. Fichtl and published by . This book was released on 1970 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: The stability to small perturbations of shear layer and jet flows (z) in atmospheres with potential temperature (z) is investigated. The problem is reduced to a chardcteristic value problem for the dimensionless wave frequency v which appears in a second-order differential equation with the dependent variable being the horizontal and temporal Fourier transform amplitude of the vertical component of the perturbation momentum vector. Broken-line profiles of E(z) and (z) are used in the analysis of this problem. Integral equations, over the domain of the fluid, which contain both quadratic forms and interfacial contributions, are derived. The interfacial terms vanish for continuous flows, and the theorems of Synge, Howard, and Miles follow. A necessary and sufficient condition for instability is also obtained for continuous flows; however, its usefulness is compromised by integrands which depend on both the basic state flow and the dependent variable of the governing differential equation.
Download or read book Instability in Geophysical Flows written by William D. Smyth and published by Cambridge University Press. This book was released on 2019-04-25 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Instabilities are present in all natural fluids from rivers to atmospheres. This book considers the physical processes that generate instability. Part I describes the normal mode instabilities most important in geophysical applications, including convection, shear instability and baroclinic instability. Classical analytical approaches are covered, while also emphasising numerical methods, mechanisms such as internal wave resonance, and simple `rules of thumb' that permit assessment of instability quickly and intuitively. Part II introduces the cutting edge: nonmodal instabilities, the relationship between instability and turbulence, self-organised criticality, and advanced numerical techniques. Featuring numerous exercises and projects, the book is ideal for advanced students and researchers wishing to understand flow instability and apply it to their own research. It can be used to teach courses in oceanography, atmospheric science, coastal engineering, applied mathematics and environmental science. Exercise solutions and MATLAB® examples are provided online. Also available as Open Access on Cambridge Core.
Download or read book Instability of Stratified Shear Flow written by Jörgen Holmboe and published by . This book was released on 1963 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulence and Coherent Structures written by O. Métais and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last 25 years, one of the most striking advances in Fluid Mecha nics was certainly the discovery of coherent structures in turbulence: lab oratory experiments and numerical simulations have shown that most turbulent flows exhibit both spatially-organized large-scale structures and disorganized motions, generally at smaller scales. The develop ment of new measurement and visualization techniques have allowed a more precise characterization and investigation of these structures in the laboratory. Thanks to the unprecedented increase of computer power and to the development of efficient interactive three-dimensional colour graphics, computational fluid dynamicists can explore the still myste rious world of turbulence. However, many problems remain unsolved concerning the origin of these structures, their dynamics, and their in teraction with the disorganized motions. In this book will be found the latest results of experimentalists, theoreticians and numerical modellers interested in these topics. These coherent structures may appear on airplane wings or slender bodies, mixing layers, jets, wakes or boundary-layers. In free-shear flows and in boundary layers, the results presented here highlight the intense three-dimensional character of the vortices. The two-dimensional large scale eddies are very sensitive to three-dimensional perturbations, whose amplification leads to the formation of three-dimensional coherent vorti cal structures, such as streamwise, hairpin or horseshoe vortex filaments. This book focuses on modern aspects of turbulence study. Relations between turbulence theory and optimal control theory in mathematics are discussed. This may have important applications with regard to, e. g. , numerical weather forecasting.
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 Instability and Turbulence in Density stratified Mixing Layers microform written by William D. (William David) Smyth and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 1990 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Instability and Turbulence in Density stratified Mixing Layers written by William David Smyth and published by . This book was released on 1990 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ocean Mixing written by Michael Meredith and published by Elsevier. This book was released on 2021-09-16 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ocean Mixing: Drivers, Mechanisms and Impacts presents a broad panorama of one of the most rapidly-developing areas of marine science. It highlights the state-of-the-art concerning knowledge of the causes of ocean mixing, and a perspective on the implications for ocean circulation, climate, biogeochemistry and the marine ecosystem. This edited volume places a particular emphasis on elucidating the key future questions relating to ocean mixing, and emerging ideas and activities to address them, including innovative technology developments and advances in methodology. Ocean Mixing is a key reference for those entering the field, and for those seeking a comprehensive overview of how the key current issues are being addressed and what the priorities for future research are. Each chapter is written by established leaders in ocean mixing research; the volume is thus suitable for those seeking specific detailed information on sub-topics, as well as those seeking a broad synopsis of current understanding. It provides useful ammunition for those pursuing funding for specific future research campaigns, by being an authoritative source concerning key scientific goals in the short, medium and long term. Additionally, the chapters contain bespoke and informative graphics that can be used in teaching and science communication to convey the complex concepts and phenomena in easily accessible ways. Presents a coherent overview of the state-of-the-art research concerning ocean mixing Provides an in-depth discussion of how ocean mixing impacts all scales of the planetary system Includes elucidation of the grand challenges in ocean mixing, and how they might be addressed
Download or read book Dynamic Instability of Stratified Shear Flow in the Upper Equatorial Pacific written by Chaojiao Sun and published by . This book was released on 1997 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulence and Mixing in Stratified Shear Flows written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A research program was carried out to investigate turbulent mixing in stably stratified shear flows with the hope of gaining an improved understanding of stably stratified nocturnal boundary layers. The program was mainly laboratory experimental, supplemented by theoretical and numerical developments. The flow configuration consisted of a three-layer system, with upper turbulent layer driven over the lower stratified, quiescent, layer while an intermediate (inversion) layer sandwiched between these two layers. The studies included the nature of instabilities, intermittent generation of turbulence, sustenance and decay of turbulence under varying background conditions (essentially determined by the Richardson number) and ensuing turbulent mixing in the inversion layer. An unprecedented volume of laboratory data were gathered during the program, which enabled to delve into the mechanics and energetics of mixing in stable boundary layers. The laboratory results were compared with, and was used to gain insights on, field observations. Also, the parameterizations developed were compared with those currently used in numerical models. A meso-scale numerical model also was used to check the efficacy of some of the laboratory-based parameterizations.
Download or read book Unstable Waves on a Sheared Density Interface written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Holmboe instability is known to occur in stratified shear layers that exhibit a relatively thin density interface compared to the shear layer thickness. At finite amplitude the instability appears as cusp-like propagating internal waves. The evolution and identification of these unstable waves is the subject of this thesis. The results are presented in four parts. First, the basic wave field resulting from Holmboe's instability is studied both numerically and experimentally. In comparing basic descriptors of the wave fields, a number of processes are identified that are responsible for differences between the simulations and experiments. These are related to variations in the mean flow that arise due to the different boundary conditions. Holmboe waves are known to produce vertical ejections of interfacial fluid from the wave crests. This `ejection process, ' in which stratified fluid is transported against buoyancy forces, is caused by the formation of a vortex couple (i.e. two vorticies of opposite sign that travel as a pair). Results obtained by means of direct numerical simulations also show that the process is primarily two-dimensional and does not require the presence of both upper and lower Holmboe modes. Shear instability is then studied in the highly stratified Fraser River estuary. The observations are found to be in good agreement with the predictions of linear theory. When instability occurs, it is largely as a result of asymmetry between regions of strong shear and density stratification. The structure of the salinity intrusion is found to depend on the strength of the freshwater discharge, in addition to the phase of the tidal cycle. This has implications for whether estuarine mixing takes place through shear instability or boundary layer turbulence. Finally, the asymmetric stratified shear layer, which exhibits a vertical shift between the density interface and the shear layer centre, is examined by the formulation of a diagnostic that is based on t.
Download or read book Turbulence in Rotating Stratified and Electrically Conducting Fluids written by P. A. Davidson and published by Cambridge University Press. This book was released on 2013-09-12 with total page 701 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are two recurring themes in astrophysical and geophysical fluid mechanics: waves and turbulence. This book investigates how turbulence responds to rotation, stratification or magnetic fields, identifying common themes, where they exist, as well as the essential differences which inevitably arise between different classes of flow. The discussion is developed from first principles, making the book suitable for graduate students as well as professional researchers. The author focuses first on the fundamentals and then progresses to such topics as the atmospheric boundary layer, turbulence in the upper atmosphere, turbulence in the core of the earth, zonal winds in the giant planets, turbulence within the interior of the sun, the solar wind, and turbulent flows in accretion discs. The book will appeal to engineers, geophysicists, astrophysicists and applied mathematicians who are interested in naturally occurring turbulent flows.
Download or read book Hydrodynamic Instability of a Three Dimensional Turbulent Shear Layer written by Ganesh Lal Harpavat and published by . This book was released on 1968 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Unsteady Combustor Physics written by Tim C. Lieuwen and published by Cambridge University Press. This book was released on 2012-08-27 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developing clean, sustainable energy systems is a pre-eminent issue of our time. Most projections indicate that combustion-based energy conversion systems will continue to be the predominant approach for the majority of our energy usage. Unsteady combustor issues present the key challenge associated with the development of clean, high-efficiency combustion systems such as those used for power generation, heating or propulsion applications. This comprehensive study is unique, treating the subject in a systematic manner. Although this book focuses on unsteady combusting flows, it places particular emphasis on the system dynamics that occur at the intersection of the combustion, fluid mechanics and acoustic disciplines. Individuals with a background in fluid mechanics and combustion will find this book to be an incomparable study that synthesises these fields into a coherent understanding of the intrinsically unsteady processes in combustors.
Download or read book Fluid Vortices written by Sheldon Green and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 905 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid Vortices is a comprehensive, up-to-date, research-level overview covering all salient flows in which fluid vortices play a significant role. The various chapters have been written by specialists from North America, Europe and Asia, making for unsurpassed depth and breadth of coverage. Topics addressed include fundamental vortex flows (mixing layer vortices, vortex rings, wake vortices, vortex stability, etc.), industrial and environmental vortex flows (aero-propulsion system vortices, vortex-structure interaction, atmospheric vortices, computational methods with vortices, etc.), and multiphase vortex flows (free-surface effects, vortex cavitation, and bubble and particle interactions with vortices). The book can also be recommended as an advanced graduate-level supplementary textbook. The first nine chapters of the book are suitable for a one-term course; chapters 10--19 form the basis for a second one-term course.
Download or read book Buoyancy Effects in Fluids written by John Stewart Turner and published by Cambridge University Press. This book was released on 1979-12-20 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: The phenomena treated in this book all depend on the action of gravity on small density differences in a non-rotating fluid. The author gives a connected account of the various motions which can be driven or influenced by buoyancy forces in a stratified fluid, including internal waves, turbulent shear flows and buoyant convection. This excellent introduction to a rapidly developing field, first published in 1973, can be used as the basis of graduate courses in university departments of meteorology, oceanography and various branches of engineering. This edition is reprinted with corrections, and extra references have been added to allow readers to bring themselves up to date on specific topics. Professor Turner is a physicist with a special interest in laboratory modelling of small-scale geophysical processes. An important feature is the superb illustration of the text with many fine photographs of laboratory experiments and natural phenomena.
