ABSTRACT
HOW efficiently a second-order model is handled is analysed for simplified equations governing waterhammer appearance in piping systems. A series solution method and a Newton-Raphson method with new calculation steps are proposed, which are efficient numerical methods, through omitting trivial terms computed within a truncation error. With fewer calculations than required previously, the proposed methods can give a solution with a required accuracy without any iteration. The second-order model, therefore, offers more accurate and efficient methods than those offered hy a first-order model. However, the second-order model causes an error in computing steady flows; ways to remove or reduce this error are shown. The validity of the analyses is examined by numerical computations in which system parameters are varied over a wide range of parameters.
