Based on experimental data of four hydraulic projects,the slopes ranging from 1∶2 to 1∶3 of stepped chutes were proposed,which has direct implications for the practical design.The simulation on the stepped flow with four slopes under the same condition was performed to verify the rationality of the step slope.The simulated results predicted the clockwise recirculating vortices and the movement of the wall-attached flow downstream.The velocity analysis proposed was helpful for understanding the energy loss caused by vortices.The vortices are fully developed when the slope is below 1∶2.The laboratory data and the simulation results showed that the energy dissipation rate reaches 60% in the slope range from 1∶2 to 1∶3,which drops down with a slope exceeding 1∶2 and increases slowly with a slope below 1∶3.
