Numerical Simulation of Water-Air Two-Phase Flow in Stilling Basin during the opening processes of radial gates

3-D numerical simulation is carried out for the water flow when the three overflow radial gates use different opening velocities. The space-time change law of hydraulic characteristics is obtained. The water surface profile in the stilling basin fluctuates greatly during the processes; the maximum pressure on the slab of stilling basin increases and moves to downstream with the gates opening; the velocity near the slab of stilling basin corresponding to the left orifice is much larger than that corresponding to the right one. The calculated water surface profile is in good agreement with the results obtained in experiments. The results can provide important basis for operation mode of radial gate.