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KSCE Journal of Civil Engineering

, Volume 9, Issue 2, pp 161–169 | Cite as

Analysis of flow structure over ogee-spillway in consideration of scale and roughness effects by using CFD model

  • Dae Geun Kim
  • Jae Hyun Park
Water Engineering

Abstract

In this study, flow characteristics such as flowrate, water surfaces, crest pressures on the ogee-spillway, and vertical distributions of velocity and pressure in consideration of model scale and surface roughness effects are investigated in detail by using the commercial CFD model, FLOW-3D, which is widely verified and used in the field of spillway flow analysis. Numerical errors in the discharge flowrate, water surfaces, and crest pressures due to the surface roughness are insignificant if we just use a general roughnessheight of construction materials, and the scale effects of the model are in an acceptable error range if the length scale ratio is less than 100 or 200. The roughness and scale effects are more severe belowh m, where the maximum velocity occurs in perpendicular coordinate to the weir crest. The velocity of the prototype is larger than that of the scaled model below but the phenomena are contrary abov eh m. Maximum velocity at any section slightly decreases as the surface roughness and the length scale ratio increase. The vertical location where maximum velocity occurs is located on a lower position as the upstream water head increases and the location almost linearly increases with the distance from the front of the spillway.

Keywords

FLOW-3D ogee-spillway roughness effect scale effect 

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References

  1. ASCE Task Committee on Hydraulic Modeling (2000).Hydraulic modeling: concepts and practice, ASCE Publications, Reston, VA.Google Scholar
  2. Assy, T. (2000). “Solution for spillway flow by finite difference method.”J. of Hydraulic Research., IAHR, Vol. 39, No. 3, pp. 241–247.Google Scholar
  3. Betts, P.L. (1979). “A variation principle in terms of stream function for free surface flows and its application to finite element method.”Comp. and Fluids, Vol. 7, No. 2, pp. 145–153.zbMATHCrossRefGoogle Scholar
  4. Bureau of Reclamation, US Department of the Interior (1980).Hydraulic laboratory techniques, Bureau of Reclamation. Denver, Colorado.Google Scholar
  5. Cassidy, J.J. (1965). “Irrotational flow over spillways of finite height.”J. of Engrg. Mech. Div., ASCE, vol. 91, No. 6, pp. 155–173.Google Scholar
  6. Flow Science (2002).FLOW-3D. [Theory manual]. Los Alamos, NM.Google Scholar
  7. Guo, Y., Wen, X., Wu, C., and Fang, D. (1998). “Numerical modeling of spillway flow with free drop and initially unknown discharge.”J. of Hydraulic Research., IAHR, Vol. 36, No. 5, pp. 785–801.CrossRefGoogle Scholar
  8. Hager, W.H. (1999).Wastewater hydraulics, Springer-Verlag, Berlin, Heidelberg, Germany.Google Scholar
  9. Ho, D.K.H. and Donohoo, S.M. (2001). “Investigation of spillway behavior under increased maximum flood by computational fluid dynamics technique.”Proc. 14th Australasian Fluid Mech. Conference, Adelaide University, Adelaide, Australia, pp. 10–14.Google Scholar
  10. Ikegawa, M. and Washizu, K. (1973). “Finite element method applied to analysis of flow over a spillway crest.”Int. J. of Numerical Methods in Engrg., Vol. 6, pp. 179–189.CrossRefGoogle Scholar
  11. Kim, N.I. (2003).Investigation of scale effects of hydraulic model for dam spillway using 3-D CFD model, [Dissertation]. Dept. of Civil Engineering, Seoul National University, Seoul, Korea.Google Scholar
  12. Li, W., Xie, Q., and Chen, C.J. (1989). “Finite analytic solution of flow over spillways.”J. of Engrg. Mech., ASCE, Vol. 115, No. 12, pp. 2635–2648.Google Scholar
  13. Olsen, N.R. and Kjellesvig, H.M. (1998). “Three-dimensional numerical flow modeling for estimation of spillway capacity.”J. of Hydraulic Research, IAHR, Vol. 36, No. 5, pp. 775–784.CrossRefGoogle Scholar
  14. Savage, B.M. and Johnson, M.C. (2001). “Flow over ogee spillway: Physical and numerical model case study.”J. of Hydraulic Engrg., ASCE, Vol. 127, No. 8, pp. 640–649.CrossRefGoogle Scholar
  15. Song, C.C.S. and Zhou, F. (1999). “Simulation of free surface flow over spillway.”J. of Hydraulic Engrg., ASCE, Vol. 125, No. 9, pp. 959–967.CrossRefGoogle Scholar
  16. Unami, K., Kawachi, T., Babar, M.M., and Itagaki, H. (1999). “Twodimensional numerical model of spillway flow.”J. of Hydraulic Engrg., ASCE, Vol. 125, No. 4, pp. 369–375.CrossRefGoogle Scholar
  17. US Army Corps of Engineers (USACE) (1988).Hydraulic design criteria, Mississippi, USA.Google Scholar
  18. US Bureau of Reclamation (USBR) (1973).Design of small dams, Washington, USA.Google Scholar
  19. Yakhot, V., Orsarg, S.A., Thangam, S., Gatski, T.B., and Speziale, C.G. (1992). “Development of turbulence models for shear flows by a double expansion technique.”Physics of Fluids, Vol. 4, No. 7, pp. 1510–1520.zbMATHMathSciNetCrossRefGoogle Scholar

Copyright information

© KSCE and Springer jointly 2005

Authors and Affiliations

  1. 1.Dept. of Civil EngineeringMokpo National UniversityKorea
  2. 2.Dept. of Civil EngineeringInje UniversityKorea

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