Article Sidebar

Download
PDF
Statistic
Read Counter : 262 Download : 280

Downloads

Download data is not yet available.

Main Article Content

Abstract

The velocity at the toe of a spillway is a major variable when designing a stilling basin. Reducing this velocity leads to reduce the size of the basin as well as the required appurtenances which needs for dissipating the surplus kinetic energy of the flow. If the spillway chute is able to dissipate more kinetic energy, then the resulting flow velocity at the toe of spillway will be reduced. Typically, stepped spillway is able to dissipate more kinetic energy than that of a smooth surface. In the present study, the typical uniform shape of the steps has been modified to a labyrinth shape. It is postulated that a labyrinth shape can increase the dissipation of kinetic energy through increasing the overlap between the forests of nappe will circulating the flow that in turns leading to further turbulence. This action can reduce the jet velocities near the surfaces, thus minimizing cavitation. At the same time the increasing of circulation regions will maximize the opportunity for air entrainment which also helps to dissipate more kinetic energy. The undertaken physical models were consisted of three labyrinth stepped spillways with magnification ratios (width of labyrinth to width of conventional step) WL/W are 1.1, 1.2, and 1.3 as well as testing a conventional stepped spillway (WL/W=1). It is concluded that the spillway chute coefficient is directly proportional to the labyrinth ratio and its value decreases as this ratio increases.

Keywords

stepped spillway labyrinth spillway energy dissipation labyrinth shape magnification ratio chute coefficient

Article Details

Creative Commons License

This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.

How to Cite
Maatooq, J. S. (2021). Predicting the Flow Velocity at the Toe of a Labyrinth Stepped Spillway. The Journal of Engineering Research [TJER], 18(1), 20–25. https://doi.org/10.53540/tjer.vol18iss1pp20-25
Download Citation
Endnote/Zotero/Mendeley (RIS)
BibTeX

References

  1. ASCE (1993) “Criteria for evaluation of watershed models” Journal of Irrigation and Drainage Eng, 119(3), pp.429–442.
  2. Boes R. M. and Hager, W. H. (2003b) "Two-phase Flow Characteristics of Stepped Spillways" Journal of Hydraulic Engineering, ASCE, 129(9), pp.661-670.
  3. Bradley J.N. and Paterka, A. J. (1957) “The hydraulic design of stilling basins” Proc., ASCE, 83, pp. 29-31.
  4. Chanson H. (2002) (ed.) "The Hydraulics of Stepped Chutes and Spillways" Steenwijk, The Netherlands: A. A. Balkema Publishers.
  5. El-Jumaily, Karim K. and Al-Lami, M.K. (2009) " Study of Conveniency of Using Stepped Spillway in Roller Compacted Concrete Dams (RCCD)" Eng. & Tech. Journal, 27(16), http://www.uotechnology.edu.iq/tec_magaz/issues2009.htm
  6. Maatooq, J.S and Ojaimi, T.J. (2014) “Evaluation the Hydraulic Aspects of Stepped Labyrinth Spillway” Eng. & Tech. Journal, 32(9)- (Ppart-A). pp. 2174-2185, http://www.uotechnology.edu.iq/tec_magaz/2014/no20149A.htm
  7. Maatooq, J.S. (2016) “Kinetic Energy Dissipation on Labyrinth Configuration Stepped Spillway” Tikrit Journal of Engineering Sciences, 23(3), pp. 12-24.
  8. Manso P.A., . and Schleiss A.J. (2002) "Stability of Concrete Macro-Roughness Linings for Overflow Protection of Earth Embankment Dams" Canadian Journal of Civil Enggineers, 29(5), pp. 762-776.
  9. Moriasi, D. N., Arnold, J. G., Van Liew M.W., Bingner R.L., Harmel R.D., and Veith T.L. (2007) “Model evaluation guidelines for systematic quantification of accuracy in watershed simulations” Trans. ASABE, 50(3), pp.885–900.
  10. Ohtsu I., Yasuda Y. and Takahashi, M., (2004) "Flow Characteristics of Skimming Flows in Stepped Channels" Journal of Hydraulic Engineering, ASCE, 130(9), pp.860-869.
  11. Tariq, J.A. and Latif, M. (2010) “Flexibility Analysis of Irrigation Outlet Structures using Simulation of Irrigation Canal Hydrodynamic Model” Irrigation Science (Published online), Springer-Veriag.
  12. Zahra, A., Afzalimehr, H., Singh, V. P. and Fattahi, R. (2015) “Prediction of flow velocity near inclined surfaces with varying roughness” International Journal of Hydraulic Engineering., 4(1), pp. 1-9.