The research focuses on how a local scour develops and evolves underneath hydraulic structures with conical gates subjected to varying operational levels and energy absorbers. Laboratory investigations were conducted to analyse how operating gate opening and flow kinematics affected scour depth and energy absorbing effectiveness. Three dampers were modelled: triangular, rectangular, and polygonal to evaluate their influences on stabilization time and cumulative movements of washouts. The findings concluded that scour depth increased in a nonlinear relationship with gate opening to a maximum of 7 cm being reached with full opening, while the triangular damper showed the highest energy absorption efficacy (16 %) through cumulative movement. The Froude number in the reinforced section did not exceed 2, while scouring intensified once flow underwent hydraulic jumps above a height of 4 m. Turbulent stresses developed in the quenching chamber, where efficiency improved with energy dissipation from the flow. The system operated most efficiently at 80% gate opening and was found to provide stable flow with lower levels of scour. The results also provide valuable information in the hydraulic design and protection of structures discharging water with conical gates.
Nurmatov et al. (Tue,) studied this question.