Hydraulics

HYDRAULICS - PREFACE - WHEN the author undertook some time ago to write this work, it was under the impression, which impression was shared by many teachers, that a book was required by Engineering students dealing with the subject of Hydraulics in a wider sense than that covered by existing text books. In addition the author felt that though several excellent text books were in existence, the large amount of experimental research carried out during the last 10 or 15 years, very little of which has been done in this country, on the subject of the flow of water, had not received the attention it deserved. The great developments in turbines and centrifugal pumps also merited some notice. An attempt has been made to embody the results of the latest researches in the book, and t. o give sufficient details to indicate the methods used in obtaining these results, especially in those cases where such information and the refkreices thereto, are likely to prove of value to those desirous of carrying out experiments on the flow of water. Perhaps in no branch of Applied Science is it more difficult to co-ordinate results and express them by general formulae than . in Hydraulics. Practical Engineers engaged in the design of water channels frequently complain of the large differences they obtain in the calculated dimensions of such channels by using the formulae put forward by different authorities. Before any formula can be used with assurance it is necessary to have some knowledge of the data used in determining the empirical constants in the formula. For this reason a little attention has been given to the historical development of the formulae for determining the flow in pipes and channels, and some particulars of the data from which the constants were determined are given. In this respect the logarithmic analysis of experimental data, especially in Chapter VI, together with the plottings of Fig. 114 and the references to experiments, will it is hoped be of assistance to engineers in enabling them to choose the coefficients suitable to given circumstances, and it is further hoped that the methods of analysis given will be educational and useful to students, and helpful in the interpretation of experiments. The chapter on the flow of water in pipes is arranged so that a student who reads as far as section 93 should be able to solve a large number of problems on flow of water in pipes, without further reading. At the end of the chapter the formulae derived in the chapter are summarised, and various kinds of practical problems solved, and arithmetical examples worked out. In the chapter on flow in channels the student who reads to section 119, and then sections 1 and 129 should be able to follow the problems at the end of the chapter, and to work the examples. Chapter V111 enables the student who is desirous of studying the elementary theory of the impact of water on vanes, and of turbines, to do so apart from the details of turbines, and the more practical problems that arise in connection with their design. The principles of construction of the various types of turbines are illustrated in Chapter IX by diagrams of the simpler and older types, as well as by drawings of the more complicated modern turbines. The drawings have been made to scale, and in particular cases sufficient dimensions are given to enable the student acquainted with the principles of machine design to design a turbine...