Abstract:
Hydraulic drops are used for energy dissipation and prevention of scouring. The flow characteristics of drops at varying slopes are complex and require experimentation for better understanding. In this present study, hydraulic model investigation is conducted to evaluate the water flow characteristics channel with abrupt drop. A 1200cm (12.00m) or (40 ft) long tilting flume was used to carry out the investigations. Several contraction geometries were inserted in the channel to reduce the height of the supercritical flow upstream of the drop section. Five drop heights of 0.25m, 0.20m, 0.15m, 0.10m and 0.05m were maintained together with five different channel slopes 0.0042, 0.0083, 0.0125, 0.0168 and 0.0212. The initial depth, sequent depth, velocity etc. were measured with different combinations of drop height and channel slope. From the entire test runs five desired parameters a1, a2, and a3 were calculated and then these five were calibrated with experimental data to relate these factors with some known variables like drop height, approach velocity and energy loss was calculated to get the desired form of Belanger’s format prediction model. The model derived indicated that as the discharge increases the energy loss increases and approach velocity decreases. The basic equation is based on the application of one dimensional momentum equation and continuity equation. The results of the experimental study were used to evaluate a developed prediction equation or computing sequent depth ratio in a channel with abrupt drop whose format is similar to the well-known Belanger equation for classical jump with modification of Froude number.
