AWWA ACE61801

In the past, most transient analysis was performed only on large transmission mains using highly skeletonized models for engineering design, and proprietary transient computer programs were largely limited to specialized consulting companies, research organizations, and universities. In addition to improved design and operation of water distribution systems, a driving force behind this trend is the increased awareness that hydraulic transients can also create unexpected opportunities for pathogens present in the external environment to intrude into the distribution system with disastrous consequences to public health. Thus, transient events cause health risks and can lead to increased leakage or decreased reliability. Transient flow simulation has become an essential requirement for assuring safety and the safe operation of drinking water distribution systems. Modern management of water distribution systems needs simulation models that are able to accurately predict transient flow and pressure variations within the distribution system environment. This paper provides a basic understanding of the physical phenomena and context of transient conditions, presents practical guidelines for their suppression and control, and describes a highly efficient Lagrangian-based simulation scheme that compares favorably with traditional Eulerian-based hydraulic transient methods for analyzing large-scale, all-pipe water distribution system models. Includes 24 references, table, figures.