Turbulence Phenomena

Turbulence Phenomena provides an introduction to the eddy transfer of momentum, mass, and heat, specifically at interfaces. The approach of the discussion of the subject matter is based on the eddy mixing length concept of Prandtl. Chapter 1 begins with a discussion on basic concepts regarding liquid flow such as viscosity, turbulent flows, and velocities. As concepts and theories are established, the book then discusses the eddy transfer in fluids, specifically eddy transfer of mass and heat within fluids and eddy transfer near solid surfaces. The concept of eddies in different surfaces is discussed in length all throughout numerous chapters. These different surfaces include clean gas-liquid surfaces, clean liquid-liquid interfaces, and film-covered surfaces. The last few chapters focus on the more detailed discussion on turbulence, such as the concept of spontaneous interfacial turbulence and emulsification and turbulent dispersion and coalescence. The book will be of great use to undergraduate students of chemical engineering, physics, and chemistry.

This book presents some of the most important results concerning atmospheric turbulence and some of its effects on the propagation of a light beam. Atmospheric turbulence causes fluctuations in both the intensity and the phase of the beam and still must be understood and modelized for applications in photonics or environmental metrology. The future of free-space optical (FSO) communication through atmospheric turbulence channels is especially of interest and research on high bit-rate communications attracts more and more interest as an alternative to radio links because of bandwidth, spectrum, and security issues. Some of the current solutions for improving FSO communications are presented in this book.

Now in its second edition, this book clearly, concisely and comprehensively outlines the essence of turbulence. In view of the absence of a theory based on first principles and adequate tools to handle the problem, the “essence” of turbulence, i.e. what turbulence really is from a fundamental point of view, is understood empirically through observations from nature, laboratories and direct numerical simulations rather than explained by means of conventional formalistic aspects, models, etc., resulting in pertinent issues being described at a highly theoretical level in spite of the mentioned lack of theory. As such, the book highlights and critically reexamines fundamental issues, especially those of paradigmatic nature, related to conceptual and problematic aspects, key misconceptions and unresolved matters, and discusses why the problem is so difficult. As in the previous edition, the focus on fundamental issues is also a consequence of the view that without corresponding advances in fundamental aspects there is little chance of progress in any applications. More generally there is a desperate need for physical fundamentals of a great variety of processes in nature and technology in which turbulence plays a central role. Turbulence is omnipresent throughout the natural sciences and technology, but despite the vast sea of information available the book retains its brevity without oversimplifications, making it of interest to a broad audience.

This book critically reexamines what turbulence really is, from a fundamental point of view and based on observations from nature, laboratories, and direct numerical simulations. It includes critical assessments and a comparative analysis of the key developments, their evolution and failures, along with key misconceptions and outdated paradigms. The main emphasis is on conceptual and problematic aspects, physical phenomena, observations, misconceptions and unresolved issues rather than on conventional formalistic aspects, models, etc. Apart from the obvious fundamental importance of turbulent flows, this emphasis stems from the basic premise that without corresponding progress in fundamental aspects there is little chance for progress in applications such as drag reduction, mixing, control and modeling of turbulence. More generally, there is also a desperate need to grasp the physical fundamentals of the technological processes in which turbulence plays a central role.

The authors present the results of numerical experiments carried out to examine the problem of development of turbulence and convection. On the basis of the results, they propose a physical model of the development of turbulence. Numerical algorithms and difference schema for carrying out numerical experiments in hydrodynamics, are proposed. Original algorithms, suitable for calculation of the development of the processes of turbulence and convection in different conditions, even on astrophysical objects, are presented. The results of numerical modelling of several important phenomena having both fundamental and applied importance are described.

The present collection of reprints covers the main contributions of David Ruelle, and coauthors, to the theory of chaos and its applications. Several of the papers reproduced here are classics in the field. Others (that were published in less accessible places) may still surprise the reader.The collection contains mathematical articles relevant to chaos, specific articles on the theory, and articles on applications to hydrodynamical turbulence, chemical oscillations, etc.A sound judgement of the value of techniques and applications is crucial in the interdisciplinary field of chaos. For a critical assessment of what has been achieved in this area, the present volume is an invaluable contribution.