Water Science and Engineering 2012, 5(1) 26-33 DOI:   10.3882/j.issn.1674-2370.2012.01.003  ISSN: 1674-2370 CN: 32-1785/TV

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Keywords
circular weir
stage-discharge relation
analytical method
Authors
Rasool GHOBADIAN
Ensiyeh MERATIFASHI
PubMed
Article by Rasool GHOBADIAN
Article by Ensiyeh MERATIFASHI

Modified theoretical stage-discharge relation for circular sharp-crested weirs

Rasool GHOBADIAN*, Ensiyeh MERATIFASHI

Department of Water Engineering, Razi University, Kermanshah 6715685438, Iran

Abstract

A circular sharp-crested weir is a circular control section used for measuring flow in open channels, reservoirs, and tanks. As flow measuring devices in open channels, these weirs are placed perpendicular to the sides and bottoms of straight-approach channels. Considering the complex patterns of flow passing over circular sharp-crested weirs, an equation having experimental correlation coefficients was used to extract a stage-discharge relation for weirs. Assuming the occurrence of critical flow over the weir crest, a theoretical stage-discharge relation was obtained in this study by solving two extracted non-linear equations. To study the precision of the theoretical stage-discharge relation, 58 experiments were performed on six circular weirs with different diameters and crest heights in a 30 cm-wide flume. The results show that, for each stage above the weirs, the theoretically calculated discharge is less than the measured discharge, and this difference increases with the stage. Finally, the theoretical stage-discharge relation was modified by exerting a correction coefficient which is a function of the ratio of the upstream flow depth to the weir crest height. The results show that the modified stage-discharge relation is in good agreement with the measured results.

Keywords circular weir   stage-discharge relation   analytical method  
Received 2011-01-13 Revised 2012-02-24 Online: 2012-03-27 
DOI: 10.3882/j.issn.1674-2370.2012.01.003
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Corresponding Authors: Rasool GHOBADIAN
Email: rsghobadian@gmail.com
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References:

Bos, M. G. 1989. Discharge Measurement Structures. Wageningen: International Institute for Land Reclamation and Improvement (ILRI).
Chow, V. T. 1959. Open-channel Hydraulics. New York: McGraw-Hill.
Greve, F. W. 1924. Semi-circular Weirs Calibrated at Purdue University. Engineering News-Record, 93(5).
Greve, F. W. 1932. Flow of Water Through Circular, Parabolic, and Triangular Vertical Notch-weirs. Lafayette: Purdue University.
Lencastre, A. 1961. Manuel D'hydraulique Générale. Paris: Eyrolles.
Panuzio, F. L., and Ramponi, F. 1936. Circular Measuring Weirs. Bureau of Reclamation.
Qu, L. Q., Yu, X. X., Xiao, J., and Lei, T. W. 2010. Development and experimental verification of a mathematical expression for the discharge rate of a semi-circular open channel. International Journal of Agriculture and Biology Engineering, 3(3), 19-26. [doi:10.3965/j.issn.1934-6344.2010.03.019-026]
Rajaratnam, N., and Muralidhar, D. 1964. End depth for circular channels. Journal of the Hydraulics Division, 90(2), 99-119.
Rickard, C., Day, R., and Purseglove, J. 2003. River Weirs:Good Practice Guide. Swindon: R&D Publication.
Staus, A. 1931. Der Beiwert kreisrunder Uberfalle. Wasserkraft und Wasserwirtschaft, 25(11), 122-123.
Stevens, J. C. 1957. Flow through circular weirs. Journal of Hydraulic Engineering, 83(6), 1455.
Vatankhah, A. R. 2010. Flow measurement using circular sharp-crested weirs. Flow Measurement and Instrumentation, 21(2), 118-122. [doi:10.1016/j.flowmeasinst.2010.01.006]

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