Hydraulic jump is a natural phenomenon at the down stream of sliding gate. The occurrence of jump depends on the tail water depth and the Froude number. In many cases, the tail water depths are too low to provoke the occurrence of jump at the desired location. Many efforts have been done to dissipate the energy of hydraulic jump by constructing a stilling basin, baffle block, endsill or the combination of that, to avoid a local scouring. An endsill or a hump at the apron is introduced as a simple structure to dissipate energy of hydraulic jump.
Base on momentum equation, an analytical solution of hydraulic jump in the upstream of endsill was developed. The same equation was developed by Forster and Skrinde using momentum equation and discharge equation through broad crested weir. Forster and Skrinde have developed also a diagram showing the relation among Froude number, ratio of sequent depth and initial depth of hydraulic jump, ratio of endsill height and initial depth of jump of an abrupt rise bed. In order to verify the proposed equation, some measurements of hydraulic jump variables for a single discharge were done in a small flume, the variation of Froude number is manipulated by applying difference gate opening.
The results of experiments show that the proposed equation is valid for determining the ratio of sequent depth and its initial depth by knowing the height of endsill and the Froude number. This equation could be used also to predict the capability of endsill to reduce the specific force of the hydraulic jump.
Keywords: hydraulic jump, endsill, momentum equatio
