Here, the effect of sill application on hydraulic jump parameters has been investigated. The model of sills is made of polyethylene in various dimensions. The sills were investigated in different positions relative to the gate in single, double, and triple arrangements. In a certain opening, the sill leads to more energy dissipation. By increasing the ratio of initial depth to sequent depth, the ∆EAB/yA decreases. It occurs due to the convergence of initial and sequent depths. In the under gate suppressed sill state, the ∆EAB/EA is 11.05% more than the upstream tangential position, while it's 14.56% for downstream specific energy. The results showed that the energy dissipation decreases with increasing the opening by at most 34.88%. In the same opening of no-sill and with sill cases, the use of suppressed sill leads to a decrease in the sequent depth compared to the no-sill one. The application of the sill causes an increase in the initial depth and accordingly the initial specific energy decreases; therefore, the sill leads to the reduction of the specific energy in the flow conjugate depths. The regression nonlinear polynomial equations were proposed to estimate the relative energy dissipation. Statistical indicators Relative Error (RE), Root Mean Square Error (RMSE), and Kling Gupta Efficiency (KGE) have been used to check the accuracy of presented equations. The mean RE% and RMSE for presented equation of ∆EAB/EA are 0.78%, and 0.004, respectively. These values are 0.87%, and 0.009 for ∆EAB/EB, respectively. The KGE is in very good range for equations.
