This book grew out of an introductory course that I was invited to teach on a number of occasions to senior and graduate level students at the University of Kid. I have cherished these opportunities in part because I was never required to conduct examinations or give grades. For the students, however, my good fortune presented special problems that induced my sympathy: in addition to having to contend with a foreign language, they would eventually have to confront an examiner with his own ideas about what they should have learned. Although I always left a copy of my lecture notes with this person, they were too sketchy to be of much use. The present book is an attempt to solve some of these problems. The content is intended to be as broad as possible within the limitations of an introductory one-semester course. It aims at providing an insightful view of present understanding, emphasizing the methods and the history of their development. In particular I have tried to expose the power of intuitive reasoning - the nature of tensor invariants, the usefulness of dimensional analysis, and the relevance of scales of physical quantities in the inference of relationships. I know of no other subject that has benefited more from these important tools, which seem to be widely neglected in the teaching of more fundamental disciplines.

The rather excessive public preoccupation of the immediate past with what has been labeled the 'environmental crisis' is now fortunately being replaced by a more sus tained and rational concern with pollution problems by public administrators, engineers, and scientists. It is to be expected that members of the engineering profes sion will in the future widely be called upon to design disposal systems for gaseous and liquid wastes which meet strict pollution control regulations and to advise on possible improvements to existing systems of this kind. The engineering decisions involved will have to be based on reasonably accurate quantitative predictions of the effects of pollutants introduced into the atmosphere, ocean, lakes and rivers. A key input for such calculations comes from the theory of turbulent diffusion, which enables the prediction of the concentrations in which pollutants may be found in the neighborhood of a release duct, such as a chimney or a sewage outfall. Indeed the role of diffusion theory in pollution prediction may be likened to the role of applied mechanics (,strength of materials') in the design of structures for adequate strength. At least a certain group of engineers will have to be proficient in applying this particular branch of science to practical problems. At present, training in the theory of turbulent diffusion is available only at the gra duate level and then only in a very few places.

The study of turbulence in the atmosphere has seen considerable progress in the last decade. To put it briefly: boundary-layer meteorology, the branch of atmospheric science that concentrates on turbulence in the lower atmosphere, has moved from the surface layer into the boundary layer itself. The progress has been made on all fronts: theoretical, numerical and observational. On the other hand, air pollution modeling has not seen such a rapid evolution. It has not benefited as much as it should have from the increasing knowledge in the field of atmospheric turbulence. Air pollution modeling is still in many ways based on observations and theories of the surface layer only. This book aims to bring the reader up to date on recent advances in boundary-layer meteorology and to pave the path for applications in air pollution dispersion problems. The text originates from the material presented during a short course on Atmospheric Turbulence and Air Pollution Modeling held in The Hague during September 1981. This course was sponsored and organized by the Royal Netherlands Meteorological Institute, xi xii PREFACE to which both editors are affiliated. The Netherlands Government Ministry of Health and Environmental Protection and the Council of Europe also gave support.

Originally published in 1955 Atmospheric Turbulence examines dynamic meteorology and the fundamental part it plays in the overall science of meteorology. The book examines the theory of atmospheric turbulence as a more mathematically developed area than largescale motions of the atmosphere and examines its significance in economic, military and industrial spheres. The book focuses on the effect and importance of atmospheric turbulence, not only to meteorologists, but the designers of large aircraft. The book addresses the effects of turbulence and the properties of the atmosphere that can be found closer to the ground. This book will be of interest to atmospheric physicists and meteorologists.

Based on his over forty years of research and teaching, John C. Wyngaard's textbook is an excellent up-to-date introduction to turbulence in the atmosphere and in engineering flows for advanced students, and a reference work for researchers in the atmospheric sciences. Part I introduces the concepts and equations of turbulence. It includes a rigorous introduction to the principal types of numerical modeling of turbulent flows. Part II describes turbulence in the atmospheric boundary layer. Part III covers the foundations of the statistical representation of turbulence and includes illustrative examples of stochastic problems that can be solved analytically. The book treats atmospheric and engineering turbulence in a unified way, gives clear explanation of the fundamental concepts of modeling turbulence, and has an up-to-date treatment of turbulence in the atmospheric boundary layer. Student exercises are included at the ends of chapters, and worked solutions are available online for use by course instructors.

This book deals with randomly moving objects and their spreading. The objects considered are particles like atoms and molecules, but also living beings such as humans, animals, plants, bacteria and even abstract entities like ideas, rumors, information, innovations and linguistic features. The book explores and communicates the laws behind these movements and reports about astonishing similarities and very specific features typical of the given object under considerations. Leading scientists in disciplines as diverse as archeology, epidemics, linguistics and sociology, in collaboration with their colleagues from engineering, natural sciences and mathematics, introduce the phenomena of spreading as relevant for their fields. An introductory chapter on “Spreading Fundamentals” provides a common basis for all these considerations, with a minimum of mathematics, selected and presented for enjoying rather than frustrating the reader.

In regions as densely populated as Western Europe, prediction of the ecological implications of pollutant transport are important in order to minimise damage in the case of accidents, and to evaluate the possible influence of existing or planned sources. In most cases, such predictions depend on high-speed computation. The present textbook presents a mathematically explicit introduction in eight chapters: 1: An introduction to the basics of fluid dynamics of the atmosphere and the local events and mesoscale processes. 2: The types of PDEs describing atmospheric flows for limited area models, the problem of appropriate boundary conditions describing the topographical constraints, and well-posedness. 3: Thermodynamics of the atmosphere, dry and wet, its stability, and radiation processes, budgets and the influence of their sum. 4: Scaling and similarity laws for stable and convective turbulent atmospheric boundary layers and the influence of inhomogeneous terrain on the advection and the vertical dispersion, and the method of large eddy simulation. 5: Statistical processes in turbulent dispersion, turbulent diffusion and chemical reactions in fluxes. 6: Theoretical modelling of diffusion and dispersion of pollutant gases. 7: The influence of urban heat production on local climate. 8: Atmospheric inversion layers and lapping inversion, the stable boundary layer and nocturnal inversion.

Since its discovery in early 1900, turbulence has been an interesting and complex area of study. Written by international experts, Air Pollution and Turbulence: Modeling and Applications presents advanced techniques for modeling turbulence, with a special focus on air pollution applications, including pollutant dispersion and inverse problems. The

The analysis and control of mixing is of great interest because of the potential for optimizing the performance of many flow processes. This monograph presents a unique overview of the physics, mathematics and state-of-the-art theoretical/numerical modeling and experimental investigations of mixing. It approaches the subject of mixing from many angles: presents theoretical and experimental results, discusses laminar and turbulent flows, considers macro and micro scales, elaborates on purely advective and advective-diffusive flows, and considers conceptual and industrial-relevant mixing devices. This monograph provides an essential reading for graduate students and postdoctoral researches interested in the investigation of mixing, and constitutes an indispensable reference for mechanical, chemical and aeronautical engineers, and applied mathematicians in universities and industries.

The transfer across the surface of environmental waters is of interest as an important phase in the geophysical and natural biochemical cycles of numer ous substances; indeed it governs the transition, one way or the other, be tween the dissolved state in the water and the gaseous state in the atmo sphere. Especially with increasing population and industrialization, gas transfer at water surfaces has become a critical factor in the understanding of the various pathways of wastes in the environment and of their engineering management. This interfacial mass transfer is, by its very nature, highly complex. The air and the water are usually in turbulent motion, and the interface be tween them is irregular, and disturbed by waves, sometimes accompanied by breaking, spray and bubble formation. Thus the transfer involves a wide variety of physical phenomena occurring over a wide range of scales. As a consequence, scientists and engineers from diverse disciplines and problem areas, have approached the problem, often with greatly differing analytical and experimental techniques and methodologies.