Numerical analysis of transient pipe flow: Steady state to comprehensive water hammer model

Various unsteady or transient models have evolved in order to achieve economy of design, construction, operation and maintenance. The specific usage of each model is strongly dependent on the level of unsteadiness in system and on the accuracy, assumptions and limitations of the applied mathematical model and its numerical solution. If designers are either too simplified or too complicated in their analysis, frustrations, inefficiencies, uncertainties, and delays multiply and may result in underdesign or overdesign; however, the overdesign doesn't necessarily indicate a higher degree of safety. In this paper, the key differences and advantage for the four transient models are compared and contrasted with respect to three criteria: their physical attributes, the practical problems they can be used to solve, and the numerical considerations of stability and accuracy.