Research on Wave Phenomena in Hydraulic Lines : 15th Report, Surge Calculus in Place of Method of Characteristics

Abstract

The method of characteristics often turns out to be too bothersome and expensive owing to the laborious evaluation process of Zielke's loss term, when it is applied to viscosity-dominant oil hydraulic pipe networks. This paper intends to present a new surge calculus which is expectedly immune from this difficulty. The fundamental idea of the calculus is based upon the simple but ever·unnoticed theoretical fact : the pressure and flow-rate waves at both ends of a single uniform pipe are linearly related to each other, regardless of the waves anywhere along the pipe between its two ends. Consequently, spatial division of a pipe along its axis required in the method of characteristics is dispensed with, which can largely save time and cost for calculation and therefore gives the present method advantages over its predecessor. Through numerical tests the usability of the method has been confirmed.