Moradpour Samad

Analysis of hydraulic jump in stilling basin of ogee spillways with negative slope and positive step

Abstract

In this investigation, characteristics of hydraulic jump in the stilling basin of an ogee spillway with adverse slopes and positive steps at the end of stilling basin have been studied. The results show that increasing the adverse slope decreases the length of roller and sequent depth, but has no effect on the relative energy loss. If the end of the jump is located inside the stilling basin, the effects of the positive step on the sequent depth and length of the roller are negligible. If the end of the jump occurs outside the stilling basin, increasing the height of positive step decreases the length of the roller and the sequent depth. It is shown that the characteristics of the jumps, whose toes are located on the curved part of the spillway are similar. If the toe of jump rises up on the straight part of the spillway, the sequent depth and length of roller considerably increase and the relative energy loss decreases. Based on the experimental data, semi-analytical equations have been presented for calculation of the sequent depth and length of the roller.