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Studies on the energy dissipation characteristics in different systems of discontinuous free surface flow in channels of circular section are reported and the results compared with those in the two classical systems of flow discontinuities described by Borda expansion in a pipe line and the plane hydraulic jump in a rectangular open channel, which are thereby seen to represent two extreme cases. Depth ratio characteristics and length ratio characteristics are also indicated. The depth ratio for a jump in a uniform circular channel is analysed using the momentum equation and is found to agree closely with experimental results.
