%0 Journal Article %T Laboratory Study of the Performance of Gabion Sill on the Energy Dissipation of Downstream of Ogee Weirs %J Iranian Journal of Soil and Water Research %I University of Tehran %Z 2008-479X %A Majedi Asl, Mahdi %A Daneshfaraz, Rasoul %A Chabokpour, Jafar %A Ghorbani, Borhan %D 2021 %\ 03/21/2021 %V 52 %N 1 %P 67-80 %! Laboratory Study of the Performance of Gabion Sill on the Energy Dissipation of Downstream of Ogee Weirs %K energy dissipation %K Sill %K Ogee weir %K Hydraulic jump length %R 10.22059/ijswr.2020.309322.668725 %X In this research, experimental evaluation of different hydraulic conditions on the performance of gabion sill in dissipating energy at downstream of Ogee spillway has been investigated. The parameters evaluated in this study included: Froude number, sill height, the amount of opening in the sill width and the diameter of the aggregates. The experiments were conducted by using flow discharges of 20 to 40 liters per second with two heights of 5 and 10 cm and openings of 10, 15, 20 and 30 cm in fixed sill widths with and without openings. The results showed by increasing the height of the sill, the relative length of the hydraulic jump increases and the amount of relative energy dissipation also increases. Also, by increasing the diameter of aggregates, the relative length of hydraulic jump and the amount of relative energy dissipation decreased. The highest amount of energy dissipation was related to aggregates with an average diameter of 1.5 cm in which the amount of energy dissipation and the length of hydraulic jump were 9 and 8.3 % more than the ones in 3 cm diameter of aggregates, respectively. The results also showed creating an opening and increasing it across the sill reduces the relative energy dissipation. So that the relative energy dissipation in the gabion with 30 cm opening was about 7% and its relative hydraulic jump length was about 9% less than the ones in sill without opening. %U https://ijswr.ut.ac.ir/article_80754_e9d46198eb56044f40774810a7a66585.pdf