Abstract:Model investigations of the primary design showed that the vertical vortex occurs at the intake of the shaft spillway. To eliminate the harmful vortex, three anti swirl piers were set around the intake. Results indicated that the anti swirl effect is good, the water level reduces and the discharge coefficient increases. The RNG k-ε turbulence model was used to simulate the conditions without and with the anti swirl pier, and the funnel shaped vertex was successfully simulated. The calculations are in agreement with the measurement data.The effect of the anti swirl pier was analyzed from the circulation angle. It was shown that the vortex formation accompanies the process of the increase of the circulation, and the circulation can be largely reduced by setting the anti swirl piers. The circulation and vorticity of the water surface while the vortex is stable were also studied. With the increase of the radius, the circulation increases and the vorticity decreases.