Chamani, M. R., and Rajaratnam, N. (1994), "Jet flow on stepped spillways", J. of Hydraulic Engineering, ASCE, Vol. 120, No. 2, pp. 254-259

 Jet flow on stepped spillways

Authors M. R. Chamani ; N. Rajaratnam
Journal Journal of Hydraulic Engineering
Year 1994
Volume 120
Number 2
pp. 254-259(6)
DOI 10.1061/(ASCE)0733-9429(1994)120:2(254)


This technical note presents a method to estimate the energy loss on stepped spillways for the jet-flow regime, which occurs when the ratio of the critical depth yc to the height of the step h is less than approximately 0.8. It introduces the concept of alpha, the proportional energy loss per step, and using the extensive experimental results of Horner, alpha; was evaluated. It was found that alpha is a function of yc/h and h/l, where l is the length of the step; and an equation has been developed that describes this variation. It was also found that the energy loss on a stepped spillway with a large number of steps can be very significant in the jet-flow regime. It also appears that for skimming flow, which occurs for yc/h larger than about 0.8, the average energy loss per step would be less than that for jet flow.

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