ABSTRACT
The preceding chapters have explored various aspects of hydraulics. In each case, a fundamental concept has been described, and where possible, that concept has been translated into an algebraic expression, which has then been used as the basis of a mathematical model. However, some problems are so complex that no adequate mathematical model can be formulated. To deal with such problems, it is necessary to find an alternative to mathematical models. One alternative that is frequently adopted is the use of scale model experiments. However, this approach also raises questions. For example, even when the experimental results have been obtained, there may be no self-evident (e.g., geometrical) relationship between the model behaviour and the behaviour of the full-scale prototype. Thus, if an engineer wishes to employ model tests, two problems must be faced: the design of the model and the experimental procedure and the correct interpretation of the results. To this end, it is necessary to identify physical laws that apply equally to the behaviour of model and prototype. In this chapter, firstly, the concepts of similarity and the theory of dimensional analysis are introduced. Next, these concepts are applied to a range of applications including pipe flow, open channel flow and hydraulic machines. Finally, the design and interpretation of the results for a range of hydraulic models including those for rivers, estuaries, coasts and hydraulic structures are presented. Worked examples and problems for solution are also given in the text.
