AWWA JAW61919

The authors compared two numerical methods, one Eulerian-based, the other Lagrangian-based, formodeling hydraulic transients in water distributionsystems. The method of characteristics (MOC), consideredto be the most accurate of the Eulerian methodsin its representation of the governing equations,requires a number of steps or calculations to solve atypical transient pipe flow problem. The wave characteristicmethod (WCM), a Lagrangian approach,tracks movement and transformation of pressurewaves and computes new conditions either at fixedintervals or only at times when a change actuallyoccurs. The WCM requires orders of magnitude fewerpressure and flow calculations, allowing large systemsto be solved in an expeditious manner. Furthermore,because the method is continuous in both time andspace, it is less sensitive to the structure of the networkand to the length of the simulation process, resultingin improved computational efficiency.Results indicated that both the MOC and WCMprovide fast and accurate results for small pipe systemsof short duration transients. However, WCM wassuperior for transient analysis of large distributionsystems because it yields accurate results in a fractionof the computational time required for MOC.Pressure transients can adversely affect the qualityof treated water because of potential intrusion bypathogens associated with transient events. Accuratemodeling studies can help utility managers determineadequate surge protection, strengthen the integrity oftheir systems, and minimize costly disruptions to service. Includes 24 references, tables, figures.

Product Details

Edition:

Vol. 97 - No. 7

Published:

07/01/2005

Number of Pages:

12

File Size:

1 file , 780 KB