Simulation of Transcritical Flow in Pipe/Channel Networks |
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Authors: | Slobodan Djordjevi? Du?an Prodanovi? Godfrey A Walters |
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Affiliation: | 1Senior Research Fellow, Dept. of Engineering, School of Engineering, Computer Science and Mathematics, Univ. of Exeter, North Park Rd., Exeter EX4 4QF, UK. E-mail: s.djordjevic@exeter.ac.uk 2Assistant Professor, Faculty of Civil Engineering, Univ. of Belgrade, P.O. Box 42, 11120 Belgrade, Serbia. E-mail: eprodano@hikom.grf.bg.ac.yu 3Professor, Dept. of Engineering, School of Engineering, Computer Science and Mathematics, Univ. of Exeter, North Park Rd., Exeter EX4 4QF, UK. E-mail: g.a.walters@exeter.ac.uk
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Abstract: | Using finite difference methods in conjunction with the reduced momentum equation and applying boundary condition structure inherent to subcritical flow to all regimes, is an approach that enables efficient numerical simulation of supercritical and transcritical flows in pipe/channel systems. However, as well as certain errors within a single channel due to incomplete equations, this technique also may introduce unwanted effects propagating across a network in both upstream and downstream directions. These may include: unrealistic backwater effects due to improper boundary conditions, nonamplifying oscillations due to jerky jump movement, and other computational instabilities. Practical implications of these are analyzed in detail and are illustrated using a set of examples. Sensitivity analyzes and comparisons with analytical solutions and laboratory experiments are made. The measures to reduce the inaccuracies inevitable in simulation of transcritical flows are discussed. |
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Keywords: | Pipe networks Simulation Pipe flow Channel flow Supercritical flow Transcritical flow Hydraulic jump Finite difference method |
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