TY - JOUR T1 - Laboratory Study of Channel Slope and Rod Diameter Effect on Intake Discharge Coefficient under Rack Floor Condition TT - بررسی آزمایشگاهی اثر شیب آبراهه و قطر میله روی ضریب تخلیه آبگیر با کف مشبک JF - JSTNAR JO - JSTNAR VL - 18 IS - 67 UR - http://jstnar.iut.ac.ir/article-1-1595-en.html Y1 - 2014 SP - 301 EP - 308 KW - Floor intake KW - Rods diameter KW - Discharge coefficient KW - Flume floor slope. N2 - Floor intake is one of the best options for diverting mountain rivers' flow. Determination of discharge diverted in different conditions of flow in main channel is one of the main objectives for intake under rack floor condition. Gradient and shape of grid rod floor can affect the discharge deviated. In this experiment, placement and gradient of grid rods and also their effects on the discharge coefficient and hydraulic parameters were investigated. For this purpose, a physical model made of glass with variable gradient was used for the main channel. To conduct and measure the discharge diverted, a sub-channel 8 meters away from the entrance of main channel was installed below the main channel. Length and width of intake entrance were 10 and 50 cm, respectively. At the entrance of intake a longitudinal grid with four different rod diameters, constant-space passing, and four different gradients were used. Meanwhile, for the investigation of flow rate four discharges were used. The results showed that intake discharge coefficient was increased with an increase in diameter of grid rod floor, reduction in floor gradient, and increasing of depth in the upstream network. In all cases, increasing the Froude number resulted in an increase in the intake discharge coefficient in the upstream network M3 ER -