Effect of Water Separation Angle and Side Channel Bottom Height on the Velocity Distribution of a Bleeder

The existing research has mainly focused on the working conditions of a right-angled bleeder.However, there is a lack of systematic research on the working conditions of a non-right angled diversion angle and an unequal bottom height between the main and branch channels, which is typically due to the terrain constraints.In this study, the diversion of a rectangular channel was simulated under different diversion angles using FLOW-3D numerical simulation.The results show that a water diversion angle of 60° is beneficial for the water diversion and sediment delivery of the main channel.The maximum transverse velocity is located at or near the surface, suggesting that the suspended sediment particles can easily enter the side channel.Furthermore, the longitudinal velocity gradient of the near bottom flow is large, and thus, the sediment particles on the bed surface easily flow downstream of the main channel, thereby reducing the possibility of siltation at the water diversion.Compared to a configuration without the side weir, the one with side weir produce an obvious layering of lateral flow velocity near the bleeder, and the main channel is more efficient for water separation and sand removal.The position and deflection amplitude of the flow dynamic axis change the velocity distribution in the bleeder region, resulting in a change in the water distribution and the erosion or deposition of bed sediment.This study provides a reference for water diversion and water distribution in irrigated areas.