Modeling of nonlinear water distribution networks by the finite element method

Abstract

A discrete Finite Element model is developed to simulate the nonlinear pressure-discharge relationship in water networks. The model is applied to several cases of water distribution networks. Of particular interest is the success of the developed model in predicting accurately the heads and pipe flows at Hanoi water network and New York water tunnels network. An advantage of the proposed model is that the initial nodal pressure heads or pipe flows need not to be prescribed a priori. The finite element method has the advantages of handling very large network sizes, ease in adding various hydraulic elements to the network, and avoiding use of artificial loops. It is found that a combination of the Secant and Newton–Raphson methods reduces significantly the number of iterations. A new form of the head loss equation is suggested which allows for variation of the roughness, pipe diameter and discharge along each pipe.