Evaluation of Submerged Vanes Effect on Hydraulic Jump Characteristics in Stilling Basins

Stilling basins are used for dissipation of kinetic energy downstream of hydraulic structures such as drops, weirs, chutes and gates. In this study hydraulic jump characteristics in presence of a submerged vane was evaluated in a flume, 12 meters long, 0.4 meters wide and 0.4 meters high. The heights of vanes were 1.1, 2.2, 3.3 and 4.4 centimeters and they were located in front of the flow with an angle of attack of 10, 20, 30 and 90 degrees. Sixty four experiments with upstream Froude numbers in the range of 3 to 8 and four different discharges of 15, 20, 25 and 30 liters per second were used in this study. Results show that use of submerged vanes can decrease length and downstream depth of hydraulic jump up to 25 and 10 percent, respectively. The bed roughness under this condition increase the bed shear stress 12 times higher compared to smooth bed and this condition occur for the vane with 4.4 centimeters hight and angle of attack of 90 degrees.