Experimental study on the effect of sediment concentration on trapezoidal hydraulic jump

Abstract

The effect of suspended sediment concentration on the characteristics of a hydraulic jump in a symmetrical trapezoidal channel was studied experimentally and compared with a classic jump. The first test series of the classical jump was performed in a rectangular flume, while the second series was conducted with two different trapezoidal side slopes. In both cases, the tests were conducted under clear water and with different concentrations (4, 8 and 12%) of fine sand of 0.22 mm as suspended sediment. The results of the tests showed that, with an increase in sediment concentration, the jump length ratio and the sequent depth ratio decreased and the energy dissipation increased. The present study considered three different sections (two sections of trapezoidal shape with side slopes of 60° and 75° and one rectangular section). A comparison of the results in flow with Fr1 = 10 for all three sections for a sediment concentration of 12% with clear water showed that the jump length ratio decreased by 14%, 22% and 18%, the sequent depth ratio decreased by 12%, 21% and 31% and the energy dissipation ratio increased by 9%, 12% and 11%, respectively. Some dimensionless relations for the prediction of jump characteristics were also developed.