Fine Scale Structure of Turbulent Velocity Fields

Fine Scale Structure of Turbulent Velocity Fields PDF Author: Frank H. Champagne
Publisher:
ISBN:
Category :
Languages : en
Pages : 19

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Book Description
An experimental investigation of three turbulent shear flows-a two-dimensional mixing layer, a high Reynolds number axisymmetric jet, and a cylinder wake-was completed. The measurements provide new information on the higher-order statistical characteristics of these flow fields and on the development of the mixing layer flow towards a self-preserving state. The relevance of initial conditions on the development of the mixing layer flow is considered in light of both present and previous data. An investigation of the validity of the Kolmogorov local similarity theories for the fine scale structure of turbulent velocity fields was undertaken. The importance of considering effects on spectra caused by deviations from Taylor's hypothesis in high intensity flows was demonstrated. Finally an experimental study of the relaminarization of turbulent pipe flow subjected to a large decrease in Reynolds number was initiated.

Fine Scale Structure of Turbulent Velocity Fields

Fine Scale Structure of Turbulent Velocity Fields PDF Author: Frank H. Champagne
Publisher:
ISBN:
Category :
Languages : en
Pages : 19

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Book Description
An experimental investigation of three turbulent shear flows-a two-dimensional mixing layer, a high Reynolds number axisymmetric jet, and a cylinder wake-was completed. The measurements provide new information on the higher-order statistical characteristics of these flow fields and on the development of the mixing layer flow towards a self-preserving state. The relevance of initial conditions on the development of the mixing layer flow is considered in light of both present and previous data. An investigation of the validity of the Kolmogorov local similarity theories for the fine scale structure of turbulent velocity fields was undertaken. The importance of considering effects on spectra caused by deviations from Taylor's hypothesis in high intensity flows was demonstrated. Finally an experimental study of the relaminarization of turbulent pipe flow subjected to a large decrease in Reynolds number was initiated.

Turbulent Flows

Turbulent Flows PDF Author: Jean Piquet
Publisher: Springer Science & Business Media
ISBN: 3662035596
Category : Technology & Engineering
Languages : en
Pages : 767

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Book Description
obtained are still severely limited to low Reynolds numbers (about only one decade better than direct numerical simulations), and the interpretation of such calculations for complex, curved geometries is still unclear. It is evident that a lot of work (and a very significant increase in available computing power) is required before such methods can be adopted in daily's engineering practice. I hope to l"Cport on all these topics in a near future. The book is divided into six chapters, each· chapter in subchapters, sections and subsections. The first part is introduced by Chapter 1 which summarizes the equations of fluid mechanies, it is developed in C~apters 2 to 4 devoted to the construction of turbulence models. What has been called "engineering methods" is considered in Chapter 2 where the Reynolds averaged equations al"C established and the closure problem studied (§1-3). A first detailed study of homogeneous turbulent flows follows (§4). It includes a review of available experimental data and their modeling. The eddy viscosity concept is analyzed in §5 with the l"Csulting ~alar-transport equation models such as the famous K-e model. Reynolds stl"Css models (Chapter 4) require a preliminary consideration of two-point turbulence concepts which are developed in Chapter 3 devoted to homogeneous turbulence. We review the two-point moments of velocity fields and their spectral transforms (§ 1), their general dynamics (§2) with the particular case of homogeneous, isotropie turbulence (§3) whel"C the so-called Kolmogorov's assumptions are discussed at length.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 568

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Book Description


Intermittency of the Fine Structure of Turbulent Velocity and Temperature Fields Measured at High Reynolds Number

Intermittency of the Fine Structure of Turbulent Velocity and Temperature Fields Measured at High Reynolds Number PDF Author: Paul John Masiello
Publisher:
ISBN:
Category : Reynolds number
Languages : en
Pages : 282

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Book Description


Turbulence Structure and Vortex Dynamics

Turbulence Structure and Vortex Dynamics PDF Author: J. C. Vassilicos
Publisher: Cambridge University Press
ISBN: 9780521781312
Category : Mathematics
Languages : en
Pages : 326

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Book Description
Edited volume on turbulence, first published in 2000.

Turbulent Flow Computation

Turbulent Flow Computation PDF Author: D. Drikakis
Publisher: Springer Science & Business Media
ISBN: 0306484218
Category : Science
Languages : en
Pages : 390

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Book Description
In various branches of fluid mechanics, our understanding is inhibited by the presence of turbulence. Although many experimental and theoretical studies have significantly helped to increase our physical understanding, a comp- hensive and predictive theory of turbulent flows has not yet been established. Therefore, the prediction of turbulent flow relies heavily on simulation stra- gies. The development of reliable methods for turbulent flow computation will have a significant impact on a variety of technological advancements. These range from aircraft and car design, to turbomachinery, combustors, and process engineering. Moreover, simulation approaches are important in materials - sign, prediction of biologically relevant flows, and also significantly contribute to the understanding of environmental processes including weather and climate forecasting. The material that is compiled in this book presents a coherent account of contemporary computational approaches for turbulent flows. It aims to p- vide the reader with information about the current state of the art as well as to stimulate directions for future research and development. The book puts part- ular emphasis on computational methods for incompressible and compressible turbulent flows as well as on methods for analysing and quantifying nume- cal errors in turbulent flow computations. In addition, it presents turbulence modelling approaches in the context of large eddy simulation, and unfolds the challenges in the field of simulations for multiphase flows and computational fluid dynamics (CFD) of engineering flows in complex geometries. Apart from reviewing main research developments, new material is also included in many of the chapters.

FINE SCALE STRUCTURE OF CONSERVED SCALAR MIXING IN TURBULENT SHEAR FLOWS: SC MUCH GREATER THAN 1 AND SC APPROXIMATELY EQUAL TO 1 (SCHMIDT NUMBER, MOLECULAR MIXING).

FINE SCALE STRUCTURE OF CONSERVED SCALAR MIXING IN TURBULENT SHEAR FLOWS: SC MUCH GREATER THAN 1 AND SC APPROXIMATELY EQUAL TO 1 (SCHMIDT NUMBER, MOLECULAR MIXING). PDF Author: KENNETH ALVAN BUCH (JR.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 498

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Book Description
the local instantaneous values of a conserved scalar and its dissipation rate.

Ten Chapters in Turbulence

Ten Chapters in Turbulence PDF Author: Peter A. Davidson
Publisher: Cambridge University Press
ISBN: 0521769442
Category : Science
Languages : en
Pages : 450

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Book Description
Leading experts summarize our current understanding of the fundamental nature of turbulence, covering a wide range of topics.

Turbulence

Turbulence PDF Author: Uriel Frisch
Publisher: Cambridge University Press
ISBN: 9780521457132
Category : Science
Languages : en
Pages : 314

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Book Description
This textbook presents a modern account of turbulence, one of the greatest challenges in physics. The state-of-the-art is put into historical perspective five centuries after the first studies of Leonardo and half a century after the first attempt by A.N. Kolmogorov to predict the properties of flow at very high Reynolds numbers. Such "fully developed turbulence" is ubiquitous in both cosmical and natural environments, in engineering applications and in everyday life. First, a qualitative introduction is given to bring out the need for a probabilistic description of what is in essence a deterministic system. Kolmogorov's 1941 theory is presented in a novel fashion with emphasis on symmetries (including scaling transformations) which are broken by the mechanisms producing the turbulence and restored by the chaotic character of the cascade to small scales. Considerable material is devoted to intermittency, the clumpiness of small-scale activity, which has led to the development of fractal and multifractal models. Such models, pioneered by B. Mandelbrot, have applications in numerous fields besides turbulence (diffusion limited aggregation, solid-earth geophysics, attractors of dynamical systems, etc). The final chapter contains an introduction to analytic theories of the sort pioneered by R. Kraichnan, to the modern theory of eddy transport and renormalization and to recent developments in the statistical theory of two-dimensional turbulence. The book concludes with a guide to further reading. The intended readership for the book ranges from first-year graduate students in mathematics, physics, astrophysics, geosciences and engineering, to professional scientists and engineers.

IUTAM Symposium on Reynolds Number Scaling in Turbulent Flow

IUTAM Symposium on Reynolds Number Scaling in Turbulent Flow PDF Author: Alexander J. Smits
Publisher: Springer Science & Business Media
ISBN: 9400709978
Category : Technology & Engineering
Languages : en
Pages : 336

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Book Description
This volume presents selected papers from the IUTAM Symposium on Reynolds Number Scaling in Turbulent Flow, convened in Princeton, NJ, USA, September I1-13, 2002. The behavior ofturbulence at high Reynolds number is interesting from a fundamental point of view, in that most theories of turbulence make very specific predictions in the limit of infinite Reynolds number. From a more practical point of view, there exist many applications that involve turbulent flow where the Reynolds numbers are extremely large. For example, large vehicles such as submarines and commercial transports operate at Reynolds 9 numbers based on length ofthe order oft0 , and industrial pipe flows cover a 7 very wide range of Reynolds numbers up to 10 • Many very important applications of high Reynolds number flow pertain to atmospheric and other geophysical flows where extremely high Reynolds numbers are the rule rather than the exception, and the understanding of climate changes and the prediction of destructive weather effects hinges to some extent on our appreciation ofhigh-Reynolds number turbulence behavior. The important effects of Reynolds number on turbulence has received a great deal of recent attention. The objective of the Symposium was to bring together many of the world's experts in this area to appraise the new experimental results, discuss new scaling laws and turbulence models, and to enhance our mutual understanding of turbulence.