Review of Open Channel Hydraulics , by Terry W. Sturm

Abstract

Despite the proliferation during recent years of textbooks on the topic of open channel hydraulics, many academics and professionals are still waiting for a book of the caliber of Henderson’s and Chow’s texts to use in the classroom or to modernize their reference library. In Sturm’s Open Channel Hydraulics, aimed at senior undergraduates and first-year graduate students, the author attempts to fill this niche by initially approaching open channel hydraulics from a fundamental perspective of fluid mechanics, and leading through to practical applications and computational solutions. He has provided chapters on introductory steady flow topics, unsteady flow theory, and numerical solutions. He also discusses flood routing and unsteady flow approximations, and the important practical consideration of flow in alluvial channels. Sturm opens with a very nice introduction that includes a brief history of our knowledge of open channel hydraulics. The introduction is followed by an overview of the topic, given in terms of definitions of the various flow approximations commonly applied in practice, placing them in their proper theoretical context. The overview is followed by a derivation of the fundamental equations of mass, momentum, and energy conservation, done reasonably, particularly with the explanation of momentum conservation, and derivation of Bernoulli’s equation and momentum’s ultimate link to the concept of energy conservation. He is perhaps a bit too succinct with the derivation of the equation of conservation of energy itself, though this is understandable given the complexity of this undertaking from a pedagogical perspective. The author takes this opportunity to impress upon the student some important fundamental concepts, including the significance of the kinetic energy and momentum correction coefficients for nonuniform velocity distributions, a highly favorable approach for an educational text, and the concepts of surface resistance versus form drag. He then provides the student with an excellent explanation and justification of the need for, and details of the application of, dimensional analysis techniques. Rather useful practice problems, particularly for the dimensional analysis technique, are provided. Following in the form of Henderson, the next two chapters introduce the reader to energy and momentum concepts. The author brings a fresh approach to these topics and presents them in an interesting manner, with immediate reference to specific examples. In addition, the complexities raised by overbank flows are introduced ~specifically in terms of multiple minimum specific energies!. The inclusion of weirs, stilling basins, and supercritical expansions and contractions in these chapters put the theory in context, and also challenges the student with complex, as well as simpler, applications of the fundamental theory. The next two chapters cover uniform and gradually varied flow, again working from a fundamental level including dimensional analysis and fluid mechanics in the case of uniform flow,