Investigate the effect of geometry and hydraulic condition on the performance of Lopac gate - Parshall flume discharge regulating structure

In this study the performance of volumetric water delivery structure of Lopac gate-Parshall flume for various geometry condition including the size of Lopac gate opening, dimensions and position of parshall flume from the lopac gate and hydraulic conditions including flow rates and the downstream condition was investigated. Analysis of results compared to the size of opening of 100 percent of the Lopac gate showed that in general, opening of 34, 45 and 68 percent in the Lopac gate dose not lead to any significant effect on the upstream depth of gate (h1), the first well of Parshall flume (ha) and the amount of energy loss (ΔE/E1) but, the size of opening of 11 and 23 percent, lead to increase h1 and ΔE/E1 up to 28.9 and 29.7 percent, respectively and also decrease ha up to 10.5 percent in the free flow condition. Comparison of the results of the Parshall flume installation positions from the Lopac gate showed that in the half and equal width of flume position installation from the gate, h1 parameter increased in 6 inch parshall flume up to 2.8 and 3.8 percent and in 9 inch parshall flume up to 4.7 and 4.3 percent to the zero position respectively. Furthermore, in 23, 34, 45 and 68 percent of size of opening of gate and all of opening of the gate in 1 foot parshall flume, there was no significant difference between the h1 parameter. Comparison of results showed that there was no significant difference between ha parameters in all installation positions of parshall flumes.