HYDRAULIC JUMP ON A SLOPING FLOOR

Abstract

Hydraulic jump is one subject which has extensively been studied in the field of hydraulic engineering. Hydraulic jump occurs when a supercritical stream meets with subcritical stream of sufficient depth. Hydraulic jumps have been widely used for energy dissipation below hydraulic structure. There has been sufficient advancement in research work on hydraulic jump in a horizontal floor, however little work has been done so on hydraulic jump in sloping channels. This study concerns with the investigation of effect of channel slopes and channel bed roughness height on hydraulic jump characteristics. To achieve this purpose the bed of flume was provided roughness by alternately spreading different size of gravels (d50 = 0.002, 0.00398, 0.0056, 0.007 and 0.011mm respectively). Three channel slopes were used viz 0.000463, 0.00986, 0.01552. In all 90 different runs were conducted with varying discharges and approach supercritical flow depth. The analysis of experimental data showed that there was no significant effect of the bed roughness heights on hydraulic jump characteristics. However channel slope significantly affected the jump characteristics. The available empirical relationships for estimating the sequent depth ratio were first checked for their accuracy by using the new data. As the existing relationships were inadequate, new relationships are proposed herein for parameters of the hydraulic jump. Comparison of observed values of sequent depth ratio, length of roller and energy loss with calculated values coming from respective proposed relationships showed satisfactory agreement. Keywords: Bed roughness height, sequent depth ratio, length of roller, energy loss. iii