Start Date

2018 4:00 PM

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Abstract

Given the enormous flow velocity, large discharge rate and narrow valley conditions, the common ski jump does not apply and the energy dissipation safety becomes a key issue in high dam engineering. The conventional slit-type flip bucket, using the design of side-wall contraction, results in high hydrodynamic pressure on the sidewalls, which is extremely dangerous to outlet structure. Based on research about motion characteristics of high speed flow, the design of leak-floor flip bucket, a kind of dovetail-shape, is proposed. When water flows through the leak-floor area, the middle of water is lifted into the atmosphere first and the natural pressure difference at lateral direction generates, making the water deflect transversely to the center-line simultaneously. This specific flipping action makes the water jet narrow-long, without high pressure on the side walls of the flip bucket. This design of leak-floor flip bucket improves structure safety, and has been successfully applied to outlet design of spillway with approximately 50m/s flow velocity. Based on physical model experimentation, the following items were addressed: (1) typical flow pattern of ski jump along the leak-floor flip bucket; (2) jet trajectory affected by the type parameters of flip bucket; and (3) pressure distribution on side-wall of flip bucket. Further, a comparison with previous results indicates a favourable behaviour of this flip bucket design for high-speed outlet.

Share

COinS
 
May 16th, 4:00 PM

Ski Jump Hydraulics of Leak-Floor Flip Bucket

Given the enormous flow velocity, large discharge rate and narrow valley conditions, the common ski jump does not apply and the energy dissipation safety becomes a key issue in high dam engineering. The conventional slit-type flip bucket, using the design of side-wall contraction, results in high hydrodynamic pressure on the sidewalls, which is extremely dangerous to outlet structure. Based on research about motion characteristics of high speed flow, the design of leak-floor flip bucket, a kind of dovetail-shape, is proposed. When water flows through the leak-floor area, the middle of water is lifted into the atmosphere first and the natural pressure difference at lateral direction generates, making the water deflect transversely to the center-line simultaneously. This specific flipping action makes the water jet narrow-long, without high pressure on the side walls of the flip bucket. This design of leak-floor flip bucket improves structure safety, and has been successfully applied to outlet design of spillway with approximately 50m/s flow velocity. Based on physical model experimentation, the following items were addressed: (1) typical flow pattern of ski jump along the leak-floor flip bucket; (2) jet trajectory affected by the type parameters of flip bucket; and (3) pressure distribution on side-wall of flip bucket. Further, a comparison with previous results indicates a favourable behaviour of this flip bucket design for high-speed outlet.