Comparison of flow fields of the arch inverted plunge cushion pool with the flat-bottomed cushion pool of Xiluodo arch dam by using 3-D numerical simulation

The flow fields of the arch-inverted plunge cushion pool and the flat-bottomed cushion pool, under the action of flood discharging of seven surface outlets, Xi Luodu high arch dam, were numerically simulated using 3-D RNG k-Ε turbulence model and rapid lid hypothesis applied in water surface. Firstly, the simulation results such as the velocity at center and on both sides as well as the wall pressure were detailedly compared with those from the hydraulic experiment on the inverted-arch pool of Xiluodu, and it was proved that they were well accordant. On a basis of this, characteristics of the flowing condition, diffusion of the velocity near the wall and the wall pressure produced by both forms of the plunge cushion pool were detailly compared. The investigation showed that both had a good side and a bad one. On the impacting zone of jets, the flowing condition and the wall pressure distribution produced in the arch inverted pool were more reasonable, while there were zones of high pressure near corners to be easily damaged for the flat-bottomed. On its downstream and upstream reaches, those in the inverted were worse.