Abstract: The characteristics of jet nappes from a trajectory bucket and their energy distribution and scour depth all depend on the shape of the energy dissipator. This paper presents numerical simulations of the jet nappe flows from a flip bucket of double narrow slot type installed on one spillway chute to explore the energy distribution and scour mechanism of the jet nappes. The characteristics of impact pressure on the scour pool bottom are analyzed. Results indicate that the impact pressure is similar to that of an ordinary oblique submerged jet, but its impacting energy is more dispersed. In the water cushion zone, the flow is structurally complicated with significant interaction between different steams. In different working conditions, the distribution of mean pressure is quite different. All this is conducive to more dissipation of energy.