Open channel flow

PrefaceAlthough this book was originally conceived as a text for use by the civilnengineering student in advanced courses either in his senior year or at graduatenlevel, it is also designed to have some appeal to the practicing engineer.Open channel flow, like any topic of engineering interest, is defined andnclassified partly by its possession of certain characteristic applications andnpartly by the principles that are invoked to deal with them. This particularnsubject is so rich in the variety and interest of its practical problems that anyntextbook on the subject is in danger of becoming a mere catalogue of applicationsnand routine techniques devised for dealing with them. But it has to benremembered that mastery of this subject, as of any other, demands a grasp ofbasic principles no less than a facility in routine operations. The practicing nengineer is reminded of this fact whenever he turns from the familiar numericsnof backwater curves and flood-routing procedures to some unusual transitionnproblem whose solution requires a good grasp of fundamentals.The importance of basic principles is recognized in this text in two ways :nfirst, by devoting the opening chapters to a fairly leisurely discussion of introductorynprinciples, including a recapitulation of the underlying argumentsnderived from the parent subject of fluid mechanics; and second, by takingnevery opportunity in the later chapters to refer back to this earlier materialnin order to clarify particular applications as they arise. It is hoped that thenpracticing engineer, as well as the student, will find this kind of treatmentnhelpful, and a compensation for the fact that not every application is pursuednthrough every possible variant that occurs in practice. Further compensationnwill, it is also hoped, be found in the fairly complete system of references andnin the unusually large number of applied topics dealt with.This insistence on the importance of principles does not imply that theynshould be given a status and significance independent of the applications theynpossess. The engineer invokes principles in order to deal with problems thatnarise in practice, and when dealing with these general principles he stillnremains in touch with the physical events which have prompted the need to generalize. This notion has dictated the structure of many chapters in thisnbook, particularly Chapters 2 and 3. In each of these, a typical basic problemnis discussed first; the theory is then developed to solve this problem, and isnfinally generalized to cover other problems as well. n n n n