With the development of industrial technology, the hydraulic machines and equipments of late have become larger in size, and the non-steady flow of fluid in the pipe conduit of the oil pressure circuit came to attract an increasing amount of attention. The analysis of this problem boils down to the question of how accurately the Navier-Stokes equation can be solved. Many a method has been proposed, which introduces the idea of the impedance and admittance in the electric circuit, in obtaining the analytical solution in a form corresponding to the frequency. However, the processes involved in the proposed solution are too complicated, and an application of these methods to the flow of fluid in the pipe conduit cannot be justified. Furthermore, these methods fail to take into consideration the influence of gravity and the elasticity of the pipe conduit.
This paper, therefore, describes an analysis of this problem by means of the characteristic curve method, taking into account the shortcomings of the abovementioned methods. The advantage of this method lies in its facility, enabling to obtain numerical solutions taking into consideration such conditions as the characteristics of the ramifications, combining and the varying calibers of the pipe. This paper also reports the manner, in which the pressure wave declines, in case the resistance arrived at through numerical calculation is in proportion to the first power of the velocity, and that in case the resistance is in proportion to the second power of the velocity.

挿図