The development of the hydraulic analogy

Abstract

This theoretical and experimental investigation has proven that accurate results can be obtained by using the hydraulic analogy. The analogy can be used in either the subsonic, transonic or supersonic range. The theory was intended to be general and showed that an exact analogy exists between free surface water flow and two dimensional gas flow. By theoretical investigation, a new channel was proposed and experiments were conducted. Remarkable correlation between theory and experiment was found and it is believed that the method presented in this thesis represents a closer approximation to the actual flow of air than any of the other present day analogies.

It has been shown that by using the analogy, the pressure, density, and temperature can be easily obtained. In addition, the shock wave phenomenon can be easily observed. This analogy would be an excellent took in demonstrating the different types of flow around bodies.

Analogy research in the field of supersonic aerodynamics is not only justified, but also necessary since the present day experimental technique in wind tunnels present economical and scientific difficulties. A large amount of knowledge can be obtained from analogy research in this field. The analogy described in the paper gives accurate results; the proposed apparatus is inexpensive, and experiments can be performed in a very short time.