Author(s): B. P. Tullis
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Keywords: No Keywords
Abstract: The condition where the tailwater exceeds a weir crest is described as a submerged-weir condition. Weir submergence can occur at low-head, run of the river control structures during flood events. A submerging tailwater condition can have several impacts on the weir function. At lowsubmergence levels (modular submergence) the free-flow head-discharge relationship is still applicable. Beyond modular submergence, a submergence-specific head-discharge relationship is required to accurately describe weir flow conditions and submergence causes the upstream flow depth to increase, relative to the free-flow condition, increasing upstream flooding potential. An experimental data set was developed by testing nine different labscale ogee crest weir geometries featuring a common H o and varied upstream and downstream weir heights. The behavior of the submerged discharge coefficients (Cs), calculated using the standard weir equation, was evaluated and compared with the U. S. Bureau of Reclamation's Cs predictive method and the original data from which it was developed.
Year: 2009