Flow Characteristics of Stilling Basin, Case Study: Karian Dam, Central Java Province

Abstract

The hydraulic jump is a process is to reduce most of the energy that occurs in spillway. It can also raises the water level in the lower reaches. A very large energy flow that must be reduced so as not to endanger the end of the dam’s overflow channel. The dissipation structure, such as stilling basin at the end of the spillway, plays a role in reducing kinetic energy flow before the flow enters the river. This paper aims to analyse the effect of the baffle block along with the layout of the stilling bed. The experiment was comparing the stilling basin without and with a baffle block, where hydraulic jump intently occurs with variation of flow rate from Q50 to QPMF. This research results that stilling basin with baffle block with a bucket angle of 23.33°has the most effective variation among the others compared to Lj and Hj values. Lj/H1 and H2/H1 has linear relationship with Froude Number (Fr), which is the higher discharge rate, the higher Lj/H1, H2/H1 and Fr value they obtain.