Abstract:In order to overcome the limitation of test study and reveal the inner field of gyrating discharge tunnel,the cavity gyrating flow of Gongboxia horizontal gyrating discharge tunnel was simulated using Realizable k-ε turbulence model based on prototype and experiment tests.The simulation results indicated that the contours of radial pressure were some concentric circles with the cavity as the center approximately and presented axial symmetrical distribution.The velocity in gyrating area and cavity area had an obvious character of zoning.Kinetic energy of gyrating area changed from the tangential momentum into the axial kinetic energy along the gyrating discharge tunnel,and the same results can be obtained from the variation of rotation angle.The cavity varied greatly with the axial and radial position in the gyrating discharge tunnel.The radial profiles of turbulent kinetic energy and turbulent dissipation rate indicated that the cavity gyrating flow remarkably enhances the efficiency of energy dissipation due to the strong turbulent water in the interface between water and air and the wall friction caused by centrifugal force.The results showed that the simulation can describe the inner field of the cavity gyrating flow objectively through comparison of hydraulic characteristics obtained by simulating and testing, and provides a reference for the application of the cavity gyrating flow in gyrating discharge tunnel.