Numerical Simulation of Jet Flow and Investigation Effect of Triangular Shape of Bucket, and Gate Opening Ratio on Flip Bucket Jet Flow Characters

If there is a high speed flow on a spillway and it is impossible to use a stilling basin because of its
high cost or installation condition, the flip bucket may be used for energy dissipation. Flow-3D
software was used in this research to simulate the flow on the chute spillway with ogee crest and
flip bucket by volume of fluid (VOF) procedure and k-ε (RNG) turbulence model. At first, the
numerical simulated trajectory of the jet flow was compared with the trajectory of the flow in the
physical model, and also with the results of USBR, US Army and Kavakami equations. Then the
effect of gate opening on the range length and the maximum height of the jet flow trajectory was
studied. At last, the effect of the circular flip bucket shape and the two kind of triangular flip bucket
named A and B on jet trajectory were studied. Results showed that USBR equation was more
accurate than the numerical model and other empirical relationships in determination of the jet
range length. Based on the results, two relationships were presented between gate opening VS
reduction percentage of the range length and the maximum height of the jet. Comparison of the
hydraulic characteristics of the circular and triangular flip buckets showed that the characters of the
triangular flip bucket type A was more similar to that of the circular flip buckets in comparison to
the type B and due to its easier implementation could be used instead of the circular flip bucket. In
addition, results of the numerical model showed error ranges length of 12 and 8 percent for the
maximum jet range length and maximum height, respectively. Therefore, applying numerical model
of Flow-3D in estimating effects of bucket shape is recommended.