Hydraulic Design of Stepped Spillways
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VIEW THE REPLYPublication: Journal of Hydraulic Engineering
Volume 129, Issue 9
Abstract
An experimental study on a large model flume using fiber-optical instrumentation indicated that the onset of skimming flow is a function of critical depth, chute angle, and step height. Uniform mixture depths that determine the height of chute sidewalls and uniform equivalent clear water depths are described in terms of a roughness Froude number containing unit discharge, chute angle and step height. The spillway length needed to attain uniform flow is expressed as a function of critical depth and chute angle. The flow resistance of stepped spillways is significantly larger than for smooth chutes due to the macro roughness of the steps. The friction factor for uniform aerated flow is of the order of 0.1 for typical gravity dam and embankment dam slopes, whereas the effect of relative roughness is rather small. The energy dissipation characteristics of stepped spillways and the design of training walls are also discussed. The paper aims to focus on significant findings of a research program and develops design guidance to lessen the need for individual physical model studies. A design example is further presented.
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References
Boes, R. M. (2000). “Zweiphasenströmung und Energieumsetzung auf Grosskaskaden.” PhD thesis, VAW, ETH Zurich, Switzerland (in German).
Boes, R. M., and Hager, W. H. (1998). “Fiber-optical experimentation in two-phase cascade flow.” Proc., Int. RCC Dams Seminar, K. Hansen, ed., Denver.
Boes, R. M., and Hager, W. H.(2003). “Two-phase flow characteristics of stepped spillways.” J. Hydraul. Eng., 129(9), 661–570.
Boes, R. M., and Minor, H.-E. (2000). “Guidelines for the hydraulic design of stepped spillways.” Proc., Int. Workshop on Hydraulics of Stepped Spillways, VAW, ETH Zurich, H.-E. Minor and W. H. Hager, eds., Balkema, Rotterdam, The Netherlands, 163–170.
Boes, R., and Minor, H.-E.(2002). “Hydraulic design of stepped spillways for RCC dams.” Hydropower Dams,9(3), 87–91.
Chamani, M. R., and Rajaratnam, N.(1999a). “Onset of skimming flow on stepped spillways.” J. Hydraul. Eng., 125(9), 969–971.
Chamani, M. R., and Rajaratnam, N.(1999b). “Characteristics of skimming flow over stepped spillways.” J. Hydraul. Eng., 125(4), 361–368.
Chanson, H. (1994). Hydraulic design of stepped cascades, channels, weirs and spillways, Pergamon, Oxford, U.K.
Chanson, H.(1996). “Prediction of the transition nappe/skimming flow on a stepped channel.” J. Hydraul. Res., 34(3), 421–429.
Chanson, H. (2000). “Experience, operation and accidents with stepped cascades.” Presented at the Int. Workshop on Hydraulics of Stepped Spillways, VAW, ETH, Zurich.
Chanson, H., Yasuda, Y., and Ohtsu, I. (2000). “Flow resistance in skimming flow: A critical review.” Proc., Int. Workshop on Hydraulics of Stepped Spillways, VAW, ETH Zurich, H.-E. Minor and W. H. Hager, eds., Balkema, Rotterdam, The Netherlands, 95–102.
Chow, V. T. (1959). Open channel hydraulics, McGraw-Hill, New York.
Frizell, K. H., Smith, D. H., and Ruff, J. F. (1994). “Stepped overlays proven for use in protecting overtopped embankment dams.” Proc., ASDSO Annual Conf., Boston.
Hager, W. H.(1991). “Uniform aerated chute flow.” J. Hydraul. Eng., 117(4), 528–533.
Hager, W. H., and Blaser, F.(1998). “Drawdown curve and incipient aeration for chute flow.” Can. J. Civ. Eng., 25(3), 467–473.
Hager, W. H., and Boes, R. M. (2000). “Backwater and drawdown curves in stepped spillway flow.” Proc., Int. Workshop on Hydraulics of Stepped Spillways, VAW, ETH Zurich, H.-E. Minor and W. H. Hager, eds., Balkema, Rotterdam, The Netherlands, 129–136.
Homann, C., Schramm, J., Demny, G., and Köngeter, J. (2000). “Wellenerscheinungen in der Hochwasserentlastungskaskade der Sorpetalsperre.” Proc., 2. Ju Wi-Treffen, VAW, ETH Zurich, Switzerland, 30–32 (in German).
James, C. S.(2001). “Discussion of ‘Onset of skimming flow on stepped spillways’ by M. R. Chamani and N. Rajaratnam.” J. Hydraul. Eng., 127(6), 519.
Marchi, E.(1961). “Il moto uniforme delle correnti liquide nei condotti chiusi e aperti.” Energ. Elet., 38(4), 289–301,
IBID38(5), 393–413 (in Italian).
Matos, J.(2000a). “Discussion of ‘Hydraulics of skimming flow on modeled stepped spillways’ by G. G. S. Pegram, A. K. Officer, and S. R. Mottram.” J. Hydraul. Eng., 126(12), 948–950.
Matos, J.(2000b). “Discussion of ‘Characteristics of skimming flow over stepped spillways’ by M. R. Chamani and N. Rajaratnam.” J. Hydraul. Eng., 126(11), 865–869.
Matos, J.(2001). “Discussion of ‘Onset of skimming flow on stepped spillways’ by M. R. Chamani and N. Rajaratnam.” J. Hydraul. Eng., 127(6), 519–521.
Matos, J., and Quintela, A. (1995). “Guidelines for the hydraulic design of stepped spillways for concrete dams.” ICOLD Energy Dissipation Bull..
Matos, J., Sanchez, M., Quintela, A., and Dolz, J. (1999). “Characteristic depth and pressure profiles in skimming flow over stepped spillways.” Proc., 28th IAHR Congress, (CD-ROM) H. Bergmann, R. Krainer, and H. Breinhälter, eds., Graz, Austria B14.
Ohtsu, I., and Yasuda, Y. (1997). “Characteristics of flow conditions on stepped channels.” Proc., 27th IAHR Congress, F. M. Holly and A. Alsaffar, eds., San Francisco, 583–588.
Ohtsu, I., Yasuda, Y., and Takahashi, M.(2000). “Discussion of ‘Hydraulics of skimming flow on modeled stepped spillways’ by G. G. S. Pegram, A. K. Officer, and S. R. Mottram.” J. Hydraul. Eng., 126(12), 950–951.
Ohtsu, I., Yasuda, Y., and Takahashi, M.(2001). “Discussion of ‘Onset of skimming flow on stepped spillways’ by M. R. Chamani and N. Rajaratnam.” J. Hydraul. Eng., 127(6), 522–524.
Rajaratnam, N.(1990). “Skimming flow in stepped spillways.” J. Hydraul. Eng., 116(4), 587–591.
Schläpfer, D. (2000). “Treppenschussrinnen.” MSc thesis, VAW, ETH Zurich, Switzerland (in German).
Schröder, R. C. M. (1990). “Hydraulische Methoden zur Erfassung von Rauheiten.” DVWK Bull. 92, Paul Parey, Germany (in German).
Stephenson, D.(1991). “Energy dissipation down stepped spillways.” Int. Water Power Dam Constr., 43(9), 27–30.
Tatewar, S. P., Ingle, R. N., and Porey, P. D.(2001). “Discussion of ‘Onset of skimming flow on stepped spillways,’ by M. R. Chamani and N. Rajaratnam.” J. Hydraul. Eng., 127(6), 524.
Tozzi, M. J. (1992). “Caracterização/comportamento de escoamentos em vertedouros com paramento em degraus.” PhD thesis. Univ. of São Paulo, Sao Paulo, Brazil (in Portuguese).
Wahrheit-Lensing, A. (1996). “Selbstbelüftung und Energieumwandlung beim Abfluss über treppenförmige Entlastungsanlagen.” PhD thesis, Univ. of Karlsruhe, Karlsruhe, Germany (in German).
Yasuda, Y., and Ohtsu, I. (1999). “Flow resistance of skimming flows in stepped channels.” Proc., 28th IAHR Congress, H. Bergmann, R. Krainer, and H. Breinhälter, eds. (CD-ROM), Graz, Austria, B14.
Yildiz, D., and Kas, I.(1998). “Hydraulic performance of stepped chute spillways.” Hydropower Dams,5(4), 64–70.
Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 129 • Issue 9 • September 2003
Pages: 671 - 679
Copyright
Copyright © 2003 American Society of Civil Engineers.
History
Received: Dec 7, 2001
Accepted: Feb 25, 2003
Published online: Aug 15, 2003
Published in print: Sep 2003
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