Download or read book The Efficiency of Turbulent Mixing in Stratified Fluids written by Guenther Wolfgang Ebert and published by . This book was released on 2010 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mixing is a common feature of stratified fluids. In stratified fluids the density varies with the height. This is true for the most fluids in geophysical environments, like lakes, the atmosphere or the ocean. Turbulent mixing plays a crucial role for the overall energy budget of the earth and has therefore an huge impact on the global climate. By introducing the mixing efficiency, it is possible to quantify mixing. It is defined as the ratio of gain of potential energy to the injection of mechanical energy. In the ocean energy provided by tidal forces leads to turbulence and thus highly dense water is lifted up from the deep sea to the surface. For this process, a mixing efficiency of 0.2 is estimated. Until now it is not completely understood how this high value can be achieved. Thus we measured the mixing efficiency by using a Couette-Taylor system, which can produce steady-state homogeneous turbulence. This is similar to what we find in the ocean. The Couette-Taylor system consists of two concentric cylinders that can be rotated independently. In between a stratified fluid is filled using salt as a stratifying agent. In the laboratory experiment, we obtained mixing efficiencies in the order of 0.001 as a result. Moreover we found that the mixing efficiency decreases with decreasing stratification like previous laboratory experiments have shown. As this value is two orders of magnitude smaller than what we find in the ocean, further studies will be necessary.
Download or read book Turbulent Mixing in Stratified Fluids written by Young-Gyu Park and published by . This book was released on 1993 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: A turbulent mixing experiment was conducted to observe the dynamics and the energetics of layer formation along with the region of layer formation in the Reynolds number (Re) and the overall Richardson number (Rio) space. A salt stratified fluid was mixed uniformly throughout its depth with a vertical rod that moved horizontally at a constant speed. The evolution of density was measured with a conductivity probe. As the instability theory of Phillips (1972) and Posmentier (1977) shows, an initially uniform density profile turns into a series of steps when Rio is larger than a critical value Ric, which forms a stability boundary. For fixed Re, as Rio decreases to Ric, the steps get weaker; the density difference across the interface and the difference of density gradient between layers and interfaces become small. Ric increases as Re increases with a functional relation log Ric ~ Re/900. The steps evolve over time, with small steps forming first, and larger steps appearing later through merging and decay of the interfaces. After some time the interior seems to reach an equilibrium state and the evolution of the interior steps stops. The length scale of the equilibrium step, ls, is a linear function of U /Ni, where U is the speed of the rod and Ni is the buoyancy frequency of the initial profile. The functional relationship is ls = 2.6U / Ni + l. Ocm. For Rio Ric, the mixing efficiency, Rf, monotonically decreases to the end of a run. However, for Rio Ric, the evolution of Rf is closely related to the evolution of the density field. Rf changes rapidly during the initiation of the steps. For Rio” Ric, R1 increases initially, while for Rio e"Ric, Rf ecreases initially. When the interior reaches an equilibrium state, Rf becomes uniform. Posmentier (1977) theorized that when steps reach an equilibrium state, a density flux is independent of the density gradient. The present experiments show a uniform density flux in the layered interior irrespective of the density structure, and this strongly supports the theory of Posmentier. The density flux generated in the bottom boundary mixed layer goes through the interior all the way to the top boundary mixed layer without changing the interior density structure. Thus, turbulence can transport scalar properties further than the characteristic length scale of active eddies without changing a density structure. When the fluid becomes two mixed layers, the relation between Rf and Ril was found for Ril> 1. Here, Ril is the local Richardson number based on the thickness of the interface. R, does decrease as Ril increases, which is the most crucial assumption of the instability theory.
Download or read book Turbulent Mixing of Density Stratified Fluids written by Men-Cheh Tao and published by . This book was released on 1971 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulence in Mixing Operations written by Robert Brodkey and published by Elsevier. This book was released on 2012-12-02 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence in Mixing Operations: Theory and Application to Mixing and Reaction presents a summary of the current status of research on turbulent motion, mixing, and kinetics. Each chapter of this book discusses turbulence in the context of mixing and reaction in scalar fields. Chapters I and III discuss the classification of turbulent reacting systems and the different possibilities in this context. Chapter II reviews the properties of passive mixing. Chapter IV looks at turbulent mixing in chemically reactive flows. Chapter V uses different techniques to make parallel numerical calculations of both mixing and reaction. Finally, Chapter VI reviews turbulence and actual industrial mixing operations. This book will be of great value for chemical and industrial engineers, especially for those interested in turbulent and industrial mixing.
Download or read book Small Scale Turbulence and Mixing in the Ocean written by J.C.J. Nihoul and published by Elsevier. This book was released on 1988-05-01 with total page 557 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of the 19th International Liège Colloquium on Ocean Hydrodynamics, the programme of which focused on the relationships between small-scale mixing and large-scale features, transports and processes. The presentation of papers on various methods of parameterization of small-scale turbulent mixing for numerical ocean models was particularly encouraged and this resulted in more than a third of the papers presented at the Colloquium dealing in one way or another with the parameterization problems; many of these papers demonstrate the direct results of modelling. These proportions are well reflected in this volume of proceedings and thus emphasize once more the importance of small-scale turbulence research for such vital practical applications as ocean modelling and forecasting.
Download or read book Turbulent Mixing in Stably stratified Fluids Subjected to Zero mean Shear written by Imad Awni Hannoun and published by . This book was released on 1987 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies on Turbulent Mixing in Stably Stratified Fluids written by M. Harindra Joseph S. Fernando and published by . This book was released on 1983 with total page 232 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 Turbulent Mixing in Nonreactive and Reactive Flows written by S. Murthy and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence, mixing and the mutual interaction of turbulence and chemistry continue to remain perplexing and impregnable in the fron tiers of fluid mechanics. The past ten years have brought enormous advances in computers and computational techniques on the one hand and in measurements and data processing on the other. The impact of such capabilities has led to a revolution both in the understanding of the structure of turbulence as well as in the predictive methods for application in technology. The early ideas on turbulence being an array of complicated phenomena and having some form of reasonably strong coherent struc ture have become well substantiated in recent experimental work. We are still at the very beginning of understanding all of the aspects of such coherence and of the possibilities of incorporating such structure into the analytical models for even those cases where the thin shear layer approximation may be valid. Nevertheless a distinguished body of "eddy chasers" has come into existence. The structure of mixing layers which has been studied for some years in terms of correlations and spectral analysis is also getting better understood. Both probability concepts such as intermittency and conditional sampling as well as the concept of large scale structure and the associated strain seem to indicate possibilities of distinguishing and synthesizing 'engulfment' and molecular mixing.
Download or read book Turbulent Mixing in a Rotating Stratified Fluid written by Yign Noh and published by . This book was released on 1987 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulence in the Ocean written by Monin and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Four years have elapsed since the preparation of the original Russian version of this book. This is a long time when dealing with such actively expanding fields of oceanography as research into small-scale structures and the investigation of hydro physical processes. Over this period new quick-response devices have been developed and successfully used for measurements taken in various ocean areas. Improvements in high-frequency meters used to measure hydrophysical parameters has enabled workers to obtain more accurate absolute values of the fluctuations measured by such devices. In view of this scientific progress, some of the ideas presented in this book now require additional explanation. Great care should be used in dealing with the absolute fluctuation values of hydro physical fields, since the methods used for the determination of the accuracy of the high-frequency measuring devices have been imperfect in the past. Never theless, it would appear that the results of the investigations summarized in this book have not lost their importance, and that the established laws governing small-scale pro cesses in the ocean are of a sufficiently universal nature and, as such, have not been shattered with the qualitative and quantitative advances in devices used for measurements taken in oceans. The authors feel that their work is of interest to English-speaking readers. The appearance of the English translation of the book is, to a very large extent, due to the tremendous amount of editing work brilliantly done by Prof. H. Tennekes.
Download or read book An Experimental Comparison of Two Theories for Turbulent Mixing in a Linearly Stratified Fluid written by Timothy P. Cox and published by . This book was released on 1981 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mixing and Dispersion in Flows Dominated by Rotation and Buoyancy written by Herman J.H. Clercx and published by Springer. This book was released on 2017-10-24 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents a state-of-the-art overview of current developments in the field in a way accessible to attendees coming from a variety of fields. Relevant examples are turbulence research, (environmental) fluid mechanics, lake hydrodynamics and atmospheric physics. Topics discussed range from the fundamentals of rotating and stratified flows, mixing and transport in stratified or rotating turbulence, transport in the atmospheric boundary layer, the dynamics of gravity and turbidity currents eventually with effects of background rotation or stratification, mixing in (stratified) lakes, and the Lagrangian approach in the analysis of transport processes in geophysical and environmental flows. The topics are discussed from fundamental, experimental and numerical points of view. Some contributions cover fundamental aspects including a number of the basic dynamical properties of rotating and or stratified (turbulent) flows, the mathematical description of these flows, some applications in the natural environment, and the Lagrangian statistical analysis of turbulent transport processes and turbulent transport of material particles (including, for example, inertial and finite-size effects). Four papers are dedicated to specific topics such as transport in (stratified) lakes, transport and mixing in the atmospheric boundary layer, mixing in stratified fluids and dynamics of turbidity currents. The book is addressed to doctoral students and postdoctoral researchers, but also to academic and industrial researchers and practicing engineers, with a background in mechanical engineering, applied physics, civil engineering, applied mathematics, meteorology, physical oceanography or physical limnology.
Download or read book Modeling and Simulation of Turbulent Mixing and Reaction written by Daniel Livescu and published by Springer Nature. This book was released on 2020-02-19 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights recent research advances in the area of turbulent flows from both industry and academia for applications in the area of Aerospace and Mechanical engineering. Contributions include modeling, simulations and experiments meant for researchers, professionals and students in the area.
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 Operational Calculus and Generalized Functions written by Arthur Erdelyi and published by Courier Corporation. This book was released on 2013-07-24 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: Suitable for advanced undergraduates and graduate students, this brief monograph examines elementary and convergence theories of convolution quotients, differential equations involving operator functions, exponential functions of operators. Solutions. 1962 edition.
Download or read book Environmental Fluid Dynamics written by Jorg Imberger and published by Academic Press. This book was released on 2012-09-06 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: A broad cross-section of scientists working in aquatic environments will enjoy this treatment of environmental fluid dynamics, a foundation for elucidating the importance of hydrodynamics and hydrology in the regulation of energy.
