MODELING OF SEQUENT DEPTH RATIO FOR HYDRAULIC JUMP UNDER SLUICE GATE USING BAFFLE BLOCK AND SILL

Abstract

The sequent depth ratio as one variable of hydraulic jump characteristics under sluice gate
were studied experimentally using different configurations simulation of baffle block and sill. Experimental
research used fiberglass prototype model as horizontal channel, width (B) = 50 cm, length (L) = 9 m and
using sluice gate installed on it, width (b) = 50 cm, thick (t) = 1 cm, height (h) = 80 cm. Two models
combination of baffle block as cubic (code K, 43 running) and trapezoidal (code T, 72 running) with different
dimension installed as three row, specified location 25 cm after sluice gate. During each running test with
variation open gate (a = 1,2,3,4 cm), variation type of baffle block (K1, K2, K3; T1, T2, T3, T4), the sequent
depth, velocity distribution and Froude number were measured and analyzed. The result showed that the
modeling of sequent depth ratio in term of the initial Froude number gives the better performance for cubic
baffle block (K3, sill 2 cm and 2.7 cm, Fr = 0.16 - 0.39) with R2 = 0.9945 and trapezoidal baffle block (T4,
sill 3.6 cm, Fr = 0.26 – 0.52) with R2 = 0.9973. It concluded that using three rows configuration of baffle
block (cubic and trapezoidal baffle block) with value of blockage ratio as 50% was appropriate with USBR
standard that value blockage ratio “η” do not exceed 0.5 (depend on the width of the block (Wb), spacing
between adjacent blocks (S) and the number of baffle blocks).