Hydrodynamic properties observed at the confluence of the Huangshui River and the Yellow River

The confluence of rivers plays a pivotal role in managing river basin systems. This study focuses on the hydrodynamic characteristics of the Huangshui River and Yellow River confluence in Northwest China, utilizing a 2D hydrodynamic mathematical model of turbulent flow. The findings reveal a distinct high-velocity region at the confluence, the location and size of which are influenced by the flow ratio. Despite various hydrological scenarios, no significant water flow separation zones form at the confluence. The presence of a main stream causes a flowback area on the left and right banks of the tributary inlet, adopting a wing-shaped distribution along the flow direction. The shape of this area varies with the flow ratio. Turbulent energy concentrates in the shear layer and downstream right bank of the confluence. As the flow ratio increases, turbulent energy diminishes in the shear layer but increases in the downstream right bank. These findings offer a theoretical foundation for river management, water environmental protection, and flood control at river confluences and downstream areas.