ABSTRACT
In analogue methods, fluid flow problems are solved by setting up another physical system, such as an electric field, for which the basic governing equations are of the same form with corresponding boundary conditions as those of the fluid flow. The Hele-Shaw apparatus produces a flow pattern which is similar to that of potential flow. It is an analogy experiment known as Hele-Shaw analogy. The well-known analogy methods for fluid flow problems are the Hele-Shaw analogy, electric tank, and surface waves in a ripple tank. The uniform flow field established in the rectangular slit of Hele-Shaw apparatus can be used as the test-section for visualizing flow over many objects of practical interest. The basic governing equations of flow of an incompressible fluid with a free-surface, in which the depth of the flow is small compared to its surface wave length, forms the shallow water theory.
