Valve closure in graph-theoretical models for slow transient network analysis

A valve closure algorithm is presented for inclusion within a slow transien t (rigid water column) pipe network model. The algorithm is specifically fo rmulated for (but not limited to) node-based, graph-theoretical models and is both direct and accurate. It is distinguished from conventional approach es by its direct assignment of the final discharge at closure to zero and s ubsequent use of the head loss at the closing valve to compute the flow rat e in pipes incident to the closing valve. As a result, redistribution of re sidual flow prior to closure to these incident pipes is not required, leadi ng to a less computationally demanding and more robust algorithm than previ ously published valve closure procedures. Application of the valve closure algorithm is illustrated in a pipe network, which also nicely demonstrates again the relation between rigid water column and water hammer models.