| Abstract: |
·The Ministry of Public Works and Water Resources works for developing theirrigation networks since few years. The gate is one of the main important items in theproject of study because it controls the discharges and heads all over the networks.Many researchers studied the effect of the gate opening on the flow characteristics,others studied the effect of rectangular and trapezoidal sill on the flow characteristicsfor free or submerged flow. This study aims to investigate the effect of sill shape onthe flow characteristics by using gates as discharge measuring device for horizontalbed for free and submerged flow.Experiments will be conducted on a small glass rectangular channel (10 cmwidth) in the cases of free and submerged flow. Three different types of sill models(ellipsoidal, semi-circular, and triangular) with different heights (2, 2.5,3,3.5, and 4cm) and of different gate opening ratio to the sill heights(0.5, 0.6, 0.7, 0.8, 0.9 and1.0) will be tested using variable flow parameters.In the theoretical study, the dimensional analysis will be adopted to investigatethe different parameters affecting the flow characteristics. Moreover, the orificeequation, the energy equation, the impulse-momentum principles, and the continuityequation will be used to obtain the different correlations between the flow parametersand flow characteristics.Statistical analysis will be conducted for all experimental data to compute thecoefficients of theoretical formulae in the case of free and submerged flow. The fittedcurves between the flow parameters (upstream water depth, gate opening, downstreamwater depth, and tail water depth) for the experimental data will be plotted versus theflow characteristics ( discharge coefficient, and Froude number).Results of the analysis will be presented as a series of graphs and designcharts. The graphs show the comparison between the discharge coefficient, Froudenumber and the different flow parameters ratio to deduce the best shape of sill forfree and submerged flow. Design charts will be developed to compute the flowcharacteristics and flow parameters for silled and non-silled gated flow if the ratio ofthe present discharge to the maximum discharge and the ratio of the gate opening tothe sill height are known. The effect of sill area in the longitudinal direction on theflow characteristics will be discussed in different charts. Also, a comparison betweenthe theoretical and experimental flow characteristics will be presented. Finally, acomparison between the present work and the previous studies will be introduced fordifferent flow cases.KEY WORDS:Vertical gate, sill shape, flow characteristics, and dischargecoefficient, silled gate.
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