Hydraulic network analysis with the software package NESEI

The software package NESEI allows the steady state and time step history hydraulic analysis of complex water supply networks. It runs on a PC under MS-DOS, WINDOWS or WIN-OS/2. A menu guided user interface with a context specific help system means, that DOS-expertise is not required. Contrary to the topological restrictions imposed by the Hardy-Crossmethod our hydraulic program con deal with networks of any topology. Our mathematical algorithm (successive over-relaxation method) uses a numerical table representation of the Moody diagram instead of some specific analytical formulation and is therefore not limited to a certain flow regime. Armatures like valves, throttles, backflow preventing flaps, forward and backward pressure regulators and flow control valves may be simulated. Memory requirement and computer time increase approximately linearly with the number of nodes. A maximum of some 3000 nodes may be simulated with 640 kB RAM and over 16000 nodes with 8 MB. Operating modes for steady state computation, time step operation histories with reservoir accounting and autodimensioning of pipe diameters are possible. For the digitization of networks, data management and graphical presentation, commercial products like GIS-ARC/INFO, GISCAD and GISVIEW or AUTOCAD may be used. Data exchange with our package is performed via text and DBASE files. A rapid generation of instructive graphical result presentations is possible via menu selections and permits to achieve a high productivity for the hydraulic analysis and optimisation of supply systems. Some auxiliary utility programs allow also small stand alone installations without GIS or CAD support. A water pressure logger which may be connected at hydrants for extended periods was developed to allow an economic calibration of a hydraulic network model by field measurements. It is microprocessor-controlled, programmable via a menu form by PC and allows selective pre-event recording according to selectable triggering criteria. (author)