Review of Fluvial Hydrodynamics: Hydrodynamic and Sediment Transport Phenomena by Subhasish Dey

The book Fluvial Hydrodynamics (subtitle: Hydrodynamic and Sediment Transport Phenomena) was recently published by Springer. The author is Subhasish Dey, professor and head of the Department of Civil Engineering at the Indian Institute of Technology (IIT) of Kharagpur, in West Bengal, India. He is an associate editor of many international refereed journals related to hydrodynamics, turbulence, and sediment transport and has published more than 130 journal papers in the same fields. He is well known all over the world as an ambassador for hydraulic and sediment research because of his novel contributions to both the theoretical and experimental aspects of hydraulics and his visiting professorships at many prestigious universities and institutions.

The merit of the book is evidenced in its forewords, by the eminent professors Paweł M. Rowiński (editor-in-chief of the book series), Vladimir Nikora, Thanos Papanicolaou, Zhao-Yin Wang, and Walter H. Graf, as well as the impressive preface, which states: “A course based on this book would be appropriate for graduate and research students in hydraulic engineering and earth sciences curricula and would expected to be taught by a teacher with an active interest in this field.”

In fact, the author guides readers into the world of hydrodynamics, sediment transport, and scour in turbulent flows by describing the relevant phenomena (both physically and mathematically) through the governing equations, underlying the fundamental hypotheses and assumptions. Then he explains the importance of experimentation, introducing dimensional analysis and theory of similitude and furnishing abundant experimental data and graphical representations.

The first of the 11 chapters comprises an introduction to fluvial hydrodynamics and furnishes the properties of fluid, sediments, and sediment mixtures, including the terminal fall velocity of sediment particles in a fluid. Chapter 2 deals with the following hydrodynamic principles: rates of deformation, conservation of mass, momentum and energy, boundary layer, flow in curved channels, drag and lift concepts, and an appendix that contains Navier-Stokes and continuity equations in polar and spherical coordinates. Chapter 3 analyzes the turbulence characteristics of flow over a sediment bed, from the RANS equations to the classical theory of turbulence by Prandtl and von Kármán; from the velocity and shear stress distributions to the isotropic theory of turbulence, which is up to date with the bursting phenomenon; and the double-average methodology (DAM) for heterogeneous flow over gravel beds. The chapter also discusses the Bose-Dey universal probability theory.

Chapter 4 presents the sediment threshold theories: definition, the concepts of threshold velocity, lift force, threshold shear stress, and probabilistic entrainment are explained. It concludes with a description of the turbulence-induced entrainment concept, the threshold of nonuniform sediment motion, and finally stable channel design. Chapter 5 is devoted to bed-load transport, defining the concepts of bed shear stress, discharge, velocity, bed-forms, and probabilistic, deterministic, and equal mobility. The sediment pickup function and saltation are specially treated. The sorting and armoring of nonuniform sediment beds are also discussed. The chapter finishes with a novel discussion of the effects of bed load on velocity distribution, length scale of turbulence, and von Kármán’s κ.

Chapter 6 illustrates suspended-load transport, explaining the diffusion concept along with the governing equations, the energy concept, and the related approaches and discussing the threshold condition (also the modern Bose and Dey probabilistic approach) and the effects of suspended load on bed-load transport, velocity distribution, von Kármán’s κ, and turbulence characteristics. Chapter 7 deals with the total-load transport in terms of both indirect and direct approaches, with a focus on nonuniform sediments. Chapter 8 presents the characteristics of bed-forms (including bars), their mathematical developments (among which the recent Bose-Dey instability theory), bed features in gravel-bed streams, and finally the effects on flow resistance.

Chapter 9 introduces the reader to meandering rivers, their mathematical modeling, and braided watercourses with the mechanics of braid formation. Chapter 10 is devoted to local scouring phenomena occurring at channel contractions, downstream of structures, below horizontal pipelines, at bridge piers and abutments, and at scour countermeasures. In an appendix, the mechanism of scour due to jets is analyzed, and predictive formulas are furnished case by case. Chapter 11 presents the dimensional analysis (the Buckingham Π theorem) and the similitude theory for modeling of both immobile and mobile beds. The book ends with very useful author and subject indexes. Almost all the chapters provide clear examples and proper and updated references.

This book is a comprehensive, excellent work by an author who has a lot to say about each field of fluvial hydrodynamics, sediment transport, and scour, owing to his very wide participation in research, including both novel mathematical modeling and first-hand experimental data sets. His definitions are clear and concise; all the theories are first developed step by step and then applied to useful examples. Up-to-date discussions of turbulence constitute a particular merit of this book. Fluvial processes are widely and deeply treated. The iconography is of excellent quality and would help readers to comprehend the vast, always interesting material of study.

This book is a must for all readers, whether student, teacher, practitioner, or researcher, who are interested in either fluvial hydraulics or sedimentology.