Submerged Flows over Rectangular Weirs of Finite Crest Length
Publication: Journal of Irrigation and Drainage Engineering
Volume 140, Issue 5
Abstract
This work presents a critical analysis of submerged flow over rectangular weirs of finite crest length. For finite crest length weirs, because the existing data sets are not extensive, new experiments for these weirs with sharp-edged and rounded crest were conducted. Based on these data, a diagram is developed to show the variation of the normalized tailwater depth with where is the free flow head and is the length of the crest, to predict the onset of submergence or the modular limit. Water surface profiles of flow over weirs of finite crest length with square-edge and rounded crests were plotted to study the formation of waves in modular and submerged conditions. Characteristics length scales such as wave length and amplitude at the modularity limit and the location of the first trough downstream of the weir were measured to generalize surface profiles at different flow discharges. An empirical equation for the discharge reduction factor was also formulated. This equation has two exponents with different values for several classes of finite crest length weirs with either square edged or rounded crest.
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References
Abou-seida, M. M., and Quraishi, A. A. (1976). “A flow equation for submerged rectangular weirs.” Proc. ICE, 61(4), 685–696.
Azimi, A. H., and Rajaratnam, N. (2009). “Discharge characteristics of weirs of finite crest length.” J. Hydraul. Eng., 1081–1085.
Azimi, A. H., Rajaratnam, N., and Zhu, D. Z. (2013). “Discharge characteristics of finite crest length weirs with upstream and downstream ramps.” J. Irrig. Drain. Eng., 75–83.
Fritz, H. M., and Hager, W. H. (1998). “Hydraulics of embankment weirs.” J. Hydraul. Eng., 963–971.
Govinda Rao, N. S., and Muralidhar, D. (1963). “Discharge characteristics of weirs of finite crest width.” Houille Blanche, 18(5), 537–545.
Hager, W. H., and Schwalt, M. (1994). “Broad-crested weir.” J. Irrig. Drain. Eng., 13–26.
Kindsvater, C. E. (1964). “Discharge characteristics of Embankment-shaped weirs.” Proc., U.S. Geological Survey Water Supply Paper 1617-A, Government Printing Office, Washington, DC.
Ohtsu, I., and Yasuda, Y. (1991). “Transition from supercritical to subcritical flow at an abrupt drop.” J. Hydraul. Res., 29(3), 309–328.
Ramamurthy, A. S., Tim, U. S., and Rao, M. V. J. (1988). “Characteristics of square-edged and round-nosed broad-crested weirs.” J. Irrig. Drain. Eng., 61–73.
Schmocker, L., Halldorsdottir, B. R., and Hager, W. H. (2011). “Effect of weir face angles on circular-crested weir flow.” J. Hydraul. Eng., 637–643.
Smith, R. A. (1959). “Calibration of a submerged broad crested weir.” J. Hydraul. Div., 85(3), 1–16.
Wu, S., and Rajaratnam, N. (1996). “Submerged flow regimes of rectangular sharp-crested weirs.” J. Hydraul. Eng., 412–414.
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© 2014 American Society of Civil Engineers.
History
Received: Nov 6, 2012
Accepted: Jan 7, 2014
Published online: Feb 4, 2014
Published in print: May 1, 2014
Discussion open until: Jul 4, 2014
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