Hydrodynamic Analysis of flow in USBR Stilling Basin Types I, II, III

In the present research, USBR stilling basin Types I, II and III were simulated numerically after validation by physical model data. Regarding position of forming hydraulic jump in each type, hydrodynamic parameters such as pressure, velocity vorticity and turbulence intensity were compared and analyzed in three standard stilling basins. RNG, VOF and FAVOR models were used to simulate turbulent, free surface and solid faces, respectively. Results showed that the performance of USBR Type III and II are greater than Type I, due to significant influence of chute blocks in Type III and end sill in Type II stilling basin. Presence of obstacles during jump had little effect on the turbulence intensity but reduced turbulence in the tail water. Therefore, turbulence in the tail water of stilling basin Type II and Type III was reduced about 11.76% and 26.72%, respectively in comparison with Type I stilling basin which caused to reduce the damage in the downstream. Vorticity in Type II was about 98% and 66.6% lower than Types I and III, respectively. In tail water of this stilling basis this parameter was about zero. Moreover, stilling basin Type II reduced the energy of flow more than Type I and Type III.