The influence of main channel velocity and water depth changes on the hydrodynamic characteristics of lateral water intake in a tidal channel

Tidal channel will be affected by the intrusion of seawater, so the current and water depth in the channel will change at every moment. These changes are critical to the hydrodynamic characteristics of water intakes in tidal rivers. This paper establishes a 3D model and validates it through laboratory models, then analyzes the influences of dynamic change of flow velocity and water depth, the amplitude changes of velocity and water depth on the secondary flow in the water withdrawal process. With the increase of the main flow velocity and the decrease of the water depth, diversion width at the water intake decreases, the peak velocity increases, and the intensity of the secondary flow also increases. With the increase of the velocity of the main channel and the rate of change in water depth, the lag time of the velocity change at the water intake is also longer, and the peak velocity will be greater than the velocity of the constant flow. The influence of the water depth change is greater than that of the main channel velocity change. Combining these four factors, more sand may be washed into the inlet channel under conditions of high flow and low water depth.