EXPERIMENTAL AND NUMERICAL INVESTIGATION OF THE HYDRAULIC PERFORMANCE OF A SQUARE ORIFICE BOTTOM INTAKE IN DIFFERENT SUBCRITICAL CONDITIONS

Bottom intakes are one of the most efficient water diversion structures in rivers that have the task of transferring the flow to the collecting canal. The orifice bottom intake is used in the surface water collection and diversion network to the turbine. In the present study, the effect of different parameters of square orifice bottom intake including perforated plate longitudinal slope (S), opening area ratio (A) and number of orifices (N) on the discharge coefficient and percentage of flow passing through the perforated plate under different subcritical flow conditions in laboratory and numerical condition investigated. The results showed that parameter A and S had the highest effect on P and Cd. By increasing A from 0.01 to 0.07, the percentage of flow passing through the perforated plate has increased 7.58 times. Also, by decreasing the longitudinal slope by 10 degrees, the percentage of flow passing through the perforated plate increased by 45.57%. Also the simulation results of this structure in Flow-3D software showed that the value of P was inversely related to turbulence and pressure.