Angular momentum transport and pattern formation in medium- and wide-gap turbulent Taylor-Couette flow PDF Download
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Author: Andreas Froitzheim
Publisher: Cuvillier Verlag
ISBN: 3736960735
Category : Technology & Engineering
Languages : en
Pages : 172
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Book Description
Turbulent Taylor-Couette flow, where the fluid is confined by two coaxial and independently rotating cylinders, is experimentally investigated within this thesis for medium and wide gaps. To reveal the influence of flow patterns on the angular momentum transport, direct torque measurements, flow visualizations and particle image velocimetry are performed in two different facilities. For the largely unexplored radius ratio regime of η = 0.357, the directly measured torque features a transition as a function of shear, which is connected to the capacity of the outer cylinder to emit small-scale plumes. When the cylinders rotate slightly in counter-direction, a maximum in torque occurs at μmax = -0.123, which is induced by the formation of large-scale Taylor vortices. The contribution of these vortices to the overall momentum transport clearly exceeds the contribution of the turbulent fluctuations for η = 0.5. Furthermore, the large-scale Taylor rolls are driven by small-scale plumes and feature azimuthally traveling waves for η = 0.714. Accordingly, the angular momentum transport in medium and wide-gap turbulent Taylor-Couette flow is determined by the interaction of turbulence and flow patterns of different scales.
Author: Andreas Froitzheim
Publisher: Cuvillier Verlag
ISBN: 3736960735
Category : Technology & Engineering
Languages : en
Pages : 172
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Book Description
Turbulent Taylor-Couette flow, where the fluid is confined by two coaxial and independently rotating cylinders, is experimentally investigated within this thesis for medium and wide gaps. To reveal the influence of flow patterns on the angular momentum transport, direct torque measurements, flow visualizations and particle image velocimetry are performed in two different facilities. For the largely unexplored radius ratio regime of η = 0.357, the directly measured torque features a transition as a function of shear, which is connected to the capacity of the outer cylinder to emit small-scale plumes. When the cylinders rotate slightly in counter-direction, a maximum in torque occurs at μmax = -0.123, which is induced by the formation of large-scale Taylor vortices. The contribution of these vortices to the overall momentum transport clearly exceeds the contribution of the turbulent fluctuations for η = 0.5. Furthermore, the large-scale Taylor rolls are driven by small-scale plumes and feature azimuthally traveling waves for η = 0.714. Accordingly, the angular momentum transport in medium and wide-gap turbulent Taylor-Couette flow is determined by the interaction of turbulence and flow patterns of different scales.
Author: Victor N. Nikolaevskiy
Publisher: Springer Science & Business Media
ISBN: 9781402017339
Category : Mathematics
Languages : en
Pages : 264
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Book Description
Turbulence theory is one of the most intriguing parts of fluid mechanics and many outstanding scientists have tried to apply their knowledge to the development of the theory and to offer useful recommendations for solution of some practical problems. In this monograph the author attempts to integrate many specific approaches into the unified theory. The basic premise is the simple idea that a small eddy, that is an element of turbulent meso-structure, possesses its own dynamics as an object rotating with its own spin velocity and obeying the Newton dynamics of a finite body. A number of such eddies fills a coordinate cell, and the angular momentum balance has to be formulated for this spatial cell. If the cell coincides with a finite difference element at a numerical calculation and if the external length scale is large, this elementary volume can be considered as a differential one and a continuum parameterization has to be used. Nontrivial angular balance is a consequence of the asymmetrical Reynolds stress action at the oriented sides of an elementary volume. At first glance, the averaged dyad of velocity components is symmetrical, == However, if averaging is performed over the plane with normal nj, the principle of commutation is lost. As a result, the stress tensor asymmetry j is determined by other factors that participate in the angular momentum balance. This is the only possibility to determine a stress in engineering.
Author: C. David Andereck
Publisher: Springer Science & Business Media
ISBN: 1461534380
Category : Science
Languages : en
Pages : 351
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Book Description
Seldom does a physical system, particularly one as apparently simple as the flow of a Newtonian fluid between concentric rotating cylinders, retain the interest of scientists, applied mathematicians and engineers for very long. Yet, as this volume goes to press it has been nearly 70 years since G. I. Taylor's outstanding experimental and theoretical study of the linear stability of this flow was published, and a century since the first experiments were performed on rotating cylinder viscometers. Since then, the study of this system has progressed enormously, but new features of the flow patterns are still being uncovered. Interesting variations on the basic system abound. Connections with open flows are being made. More complex fluids are used in some experiments. The vigor of the research going on in this particular example of nonequilibrium systems was very apparent at the NATO Advanced Research Workshop on "Ordered and Turbulent Patterns in Taylor Couette Flow," held in Columbus, Ohio, USA May 22-24, 1991. A primary goal of this ARW was to bring together those interested in pattern formation in the classic Taylor Couette problem with those looking at variations on the basic system and with those interested in related systems, in order to better define the interesting areas for the future, the open questions, and the features common (and not common) to closed and open systems. This volume contains many of the contributions presented during the workshop.
Author:
Publisher:
ISBN:
Category : Mechanics, Applied
Languages : en
Pages : 354
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Book Description
Author: P. A. Davidson
Publisher: Cambridge University Press
ISBN: 1107434343
Category : Science
Languages : en
Pages : 701
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Book Description
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.
Author: Pascal Chossat
Publisher: Springer
ISBN: 9780387941547
Category : Mathematics
Languages : en
Pages : 234
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Book Description
1. 1 A paradigm About one hundred years ago, Maurice Couette, a French physicist, de signed an apparatus consisting of two coaxial cylinders, the space between the cylinders being filled with a viscous fluid and the outer cylinder being rotated at angular velocity O2. The purpose of this experiment was, follow ing an idea of the Austrian physicist Max Margules, to deduce the viscosity of the fluid from measurements of the torque exerted by the fluid on the inner cylinder (the fluid is assumed to adhere to the walls of the cylinders). At least when O is not too large, the fluid flow is nearly laminar and 2 the method of Couette is valuable because the torque is then proportional to 110 , where II is the kinematic viscosity of the fluid. If, however, O is 2 2 increased to a very large value, the flow becomes eventually turbulent. A few years later, Arnulph Mallock designed a similar apparatus but allowed the inner cylinder to rotate with angular velocity 01, while O2 = o. The surprise was that the laminar flow, now known as the Couette flow, was not observable when 0 exceeded a certain "low" critical value Ole, even 1 though, as we shall see in Chapter II, it is a solution of the model equations for any values of 0 and O .
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 892
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Book Description
Author: S. F. Dermott
Publisher:
ISBN:
Category : Mathematics
Languages : en
Pages : 360
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Book Description
A companion to earlier volumes (497, 536, 596, 617 and 631) of the Annals, this entry in the nonlinear astronomy series has contributions by most of the acknowledged experts in the field. They write on many topics, all of current interest. As several hold strong opposing views, this is a lively, important and timely publication.
Author: Peter Childs
Publisher: Elsevier
ISBN: 0123820995
Category : Science
Languages : en
Pages : 415
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Book Description
Rotating flow is critically important across a wide range of scientific, engineering and product applications, providing design and modeling capability for diverse products such as jet engines, pumps and vacuum cleaners, as well as geophysical flows.Developed over the course of 20 years’ research into rotating fluids and associated heat transfer at the University of Sussex Thermo-Fluid Mechanics Research Centre (TFMRC), Rotating Flow is an indispensable reference and resource for all those working within the gas turbine and rotating machinery industries.Traditional fluid and flow dynamics titles offer the essential background but generally include very sparse coverage of rotating flows—which is where this book comes in. Beginning with an accessible introduction to rotating flow, recognized expert Peter Childs takes you through fundamental equations, vorticity and vortices, rotating disc flow, flow around rotating cylinders and flow in rotating cavities, with an introduction to atmospheric and oceanic circulations included to help deepen understanding.Whilst competing resources are weighed down with complex mathematics, this book focuses on the essential equations and provides full workings to take readers step-by-step through the theory so they can concentrate on the practical applications. A detailed yet accessible introduction to rotating flows, illustrating the differences between flows where rotation is significant and highlighting the non-intuitive nature of rotating flow fields Written by world-leading authority on rotating flow, Peter Childs, making this a unique and authoritative work Covers the essential theory behind engineering applications such as rotating discs, cylinders, and cavities, with natural phenomena such as atmospheric and oceanic flows used to explain underlying principles Provides a rigorous, fully worked mathematical account of rotating flows whilst also including numerous practical examples in daily life to highlight the relevance and prevalence of different flow types Concise summaries of the results of important research and lists of references included to direct readers to significant further resources
Author: Alexander J. Smits
Publisher: Wiley-VCH
ISBN:
Category : Science
Languages : en
Pages : 552
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Book Description
Uncover Effective Engineering Solutions to Practical Problems With its clear explanation of fundamental principles and emphasis on real world applications, this practical text will motivate readers to learn. The author connects theory and analysis to practical examples drawn from engineering practice. Readers get a better understanding of how they can apply these concepts to develop engineering answers to various problems. By using simple examples that illustrate basic principles and more complex examples representative of engineering applications throughout the text, the author also shows readers how fluid mechanics is relevant to the engineering field. These examples will help them develop problem-solving skills, gain physical insight into the material, learn how and when to use approximations and make assumptions, and understand when these approximations might break down. Key Features of the Text * The underlying physical concepts are highlighted rather than focusing on the mathematical equations. * Dimensional reasoning is emphasized as well as the interpretation of the results. * An introduction to engineering in the environment is included to spark reader interest. * Historical references throughout the chapters provide readers with the rich history of fluid mechanics.
