APPLICATION OF FLOW-3D MODEL FOR DETERMINATION OF CONJUGATE DEPTH AND JUMP LENGTH ON A TRIANGULAR ROUGH BED

Abstract

A hydraulic jump has been widely used to dissipate excess energy downstream of the spillway. This paper presents a study on the conjugate depth and the jump length on the triangular rough bed using the Flow-3D numerical simulation tool, which uses a combination of the RNG k-e model, and the volume of fluid (VOF) method has been widely applied to simulate complex hydraulic phenomena in hydraulic works. The study has proposed four rough bed models based on the different arrangements and geometrical characteristics of rough blocks on the channel bottom, with the Froude number (Fr₁) varying from 4.8 to 9.4. The results show that four rough bed models strongly influence the hydraulic characteristics of hydraulic jumps. The conjugate depth (y₂) is reduced by 16-27% compared to a smooth bed in the same experimental conditions; the jump length (L_j) is about 30-53% less than the smooth bed.