Abstract:

To optimize the energy dissipation at the outlet of flood-discharge tunnel, characteristics of the nappes of common flip bucket and narrow-slot flip bucket(including  planar-diffusion and longitudinal diffusion energy dissipator) were systematically investigated. The controlling and diverting effect of narrow-slot bucket type on the movement locus and pattern of nappe and the contact area of jet flow into water were discussed in emphasis. Results showed that problems of energy dissipation can be well addressed  by asymmetric side-wall and partial deflection of the outlet to control and divert the nappe direction and subsequently adapt to the complex downstream channel boundary. The research could be a reference for similar projects, yet the quantitative relation between the nappe movement locus and the bucket type and size are to be studied in depth.    

Key words: hydraulics, energy dissipation and erosion control, ski-jump energy dissipation, planar diffusion flip bucket, narrow-slot flip bucket, nappe direction