TECHNICAL PAPERS
Feb 1, 1989

Flow Measurement with Trapezoidal Free Overfall

Publication: Journal of Irrigation and Drainage Engineering
Volume 115, Issue 1

Abstract

The trapezoidal free overfall is analyzed by the one‐dimensional momentum equation, including an assumed pressure distribution at the brink. The pressure distribution is based on previous measurements in rectangular and triangular open channels. The predicted relationship between brink depth and discharge is compared with experimental data from a laboratory flume, and excellent agreement is evident. A calibration chart, applicable to any mild slope trapezoidal channel, is developed theoretically and checked against the data from the present study and data from previous studies. Again excellent agreement is noted. Comparison with previous predictive techniques, in which the pressure distribution at the brink was assumed to be uniformly atmospheric, illustrates the importance of including this pressure distribution in the analysis.

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References

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2.
Christodoulou, G. C., Noutsopoulos, G. C., and Andreou, S. A. (1984). “Factors affecting brink depth in rectangular overfalls.” Proc. First Int. Conf. on Channels and Channel Control Structures, Southampton, England, Apr., Springer‐Verlag, Berlin, 1–3–1–17.
3.
Delleur, J. W., Dodge, J. C. I., and Gent, K. N. (1956). “Influence of slope and roughness on the free overfall.” J. Hydr. Engrg., ASCE, 82(HY4), 1038–30–1038‐35.
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Diskin, M. H. (1961). “End depth at a drop in trapezoidal channels.” J. Hydr. Engrg., ASCE, 87(HY4), 11–32.
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Information

Published In

Go to Journal of Irrigation and Drainage Engineering
Journal of Irrigation and Drainage Engineering
Volume 115Issue 1February 1989
Pages: 125 - 136

History

Published online: Feb 1, 1989
Published in print: Feb 1989

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Authors

Affiliations

Robert J. Keller, Member, ASCE
Sr. Lect., Dept. of Civ. Engrg., Monash Univ., Clayton 3168, Australia
Soon S. Fong
Former Grad. Scholar, Dept. of Civ. Engrg., Monash Univ., Clayton 3168, Australia

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