An efficient Lagrangian-based approach for transient modelling and analysis in urban water distribution networks

With the increasing scale and complexity of urban water distribution networks (WDN) nowadays, the efficiency of transient analysis has become a considerable concern for transient modelling and analysis of such systems. An efficient Lagrangian-based model (ELM) is developed in this paper on the basis of transient wave propagation mechanism, with the aim for efficient transient analysis in WDN. The Lagrangian event-driven scheme for reproducing and simulating pressure waves are firstly developed through the integration of wave transformations at various boundaries and pipe line frictions, as well as the consideration of data storage and transformation. Within the scheme, two efficiency control strategies - extended wave selection and minor wave truncation, are defined and embedded to compromise the computational efficiency and simulation accuracy for transient analysis. A case study of typical looped pipe network is then applied to test and verify the effectiveness and validity of this developed approach. The main results indicate that (1) the developed ELM is much more efficient than the traditional transient analysis method (e.g., MOC) for appropriate settings of these two strategies; and meanwhile, (2) the accuracy of the proposed ELM can be comparable with the MOC-based method when only the quasi-steady friction is considered. The results analysis and discussion of this study demonstrate that the developed ELM may become a feasible and useful alternative to facilitate the transient modelling and analysis in practical WDN.