The Relation Of Turbulence To Diffusion In Open Channel Flows

A review of open channel turbulence, focusing especially on certain features stemming from the presence of the free surface and the bed of a river. Part one presents the statistical theory of turbulence; Part two addresses the coherent structures in open-channel flows and boundary layers.

This book provides a general introduction to the topic of turbulent flows. Apart from classical topics in turbulence, attention is also paid to modern topics. After studying this work, the reader will have the basic knowledge to follow current topics on turbulence in scientific literature. The theory is illustrated with a number of examples of applications, such as closure models, numerical simulations and turbulent diffusion, and experimental findings. The work also contains a number of illustrative exercises Review from the Textbook & Academic Authors Association that awarded the book with the 2017 Most Promising New Textbook Award: “Compared to other books in this subject, we find this one to be very up-to-date and effective at explaining this complicated subject. We certainly would highly recommend it as a text for students and practicing professionals who wish to expand their understanding of modern fluid mechanics.”

This book discusses the subject of turbulence encountered in coastal and civil engineering.The primary aim of the book is to describe turbulence processes including transition to turbulence; mean and fluctuating flows in channels/pipes, and in currents; wave boundary layers (including boundary layers under solitary waves); streaming processes in wave boundary layers; turbulence processes in breaking waves including breaking solitary waves; turbulence processes such as bursting process and their implications for sediment transport; flow resistance in steady and wave boundary layers; and turbulent diffusion and dispersion processes in the coastal and river environment, including sediment transport due to diffusion/dispersion.Both phenomenological and statistical theories are described in great detail. Turbulence modelling is also described, and several examples for modelling of turbulence in steady flow and wave boundary layers are presented.The book ends with a chapter containing hands-on exercises on a wide variety of turbulent flows including experimental study of turbulence in an open-channel flow, using Laser Doppler Anemometry; Statistical, correlation and spectral analysis of turbulent air jet flow; Turbulence modelling of wave boundary layer flows; and numerical modelling of dispersion in a turbulent boundary layer, a set of exercises used by the authors in their Masters classes over many years.Although the book is essentially intended for professionals and researchers in the area of Coastal and Civil Engineering, and as a text book for graduate/post graduate students, the contents of the book will, however, additionally provide sufficient background in the study of turbulent flows relevant to many other disciplines, such as Wind Engineering, Mechanical Engineering, and Environmental Engineering.

A review of open channel turbulence, focusing especially on certain features stemming from the presence of the free surface and the bed of a river. Part one presents the statistical theory of turbulence; Part two addresses the coherent structures in open-channel flows and boundary layers.

This book presents numerical simulations of three-dimensional turbulent open-channel flows. In the simulations, Reynolds-averaged Navier-Stokes equations are solved with the Reynolds stress model for turbulence closure. The overall solution strategy is the SIMPLER algorithm, and the power-law scheme is used to discretise the convection and diffusion terms in the governing equations. The Reynolds stress model is applied to rectangular open-channel flows, partly-vegetated open-channel flows, and compound open-channel flows. The simulated mean flow and turbulence structures including streamwise mean velocity, secondary currents, turbulence intensity, and Reynolds stress, are provided and compared with measure data in the literature. As shown in this book, these comparisons reveal that the proposed Reynolds stress model successfully predicts the mean flow and turbulence statistics of turbulent open-channel flows.

A review of open channel turbulence, focusing especially on certain features stemming from the presence of the free surface and the bed of a river. Part one presents the statistical theory of turbulence; Part two addresses the coherent structures in open-channel flows and boundary layers.