Water Engineering Research

Korea Water Resources Association (한국수자원학회)
권호 표지

VORTEX SHEAR VELOCITY AND ITS EROSION IN THE SCOUR HOLE

  • Lee, Hong-Sik (Department of Civil Engineering, Chung-Ang University) ;
  • Kim, Jin-Hong (Department of Civil Engineering, Chung-Ang University) ;
  • Lee, Sam-Hee (Korea Institute of Construction Technology)
  • Published : 2000.10.01
Download PDF
⟨ Previous Next ⟩

Abstract

Scour hole is formed due to the high shear stress of the jet flow at the outlet of a hydraulic structure and vortex erosion occurs in the scour hole. It is important to determine the amount of vortex erosion occurs in the scour hole. It is important to determine the amount of vortex erosion for the design of bed protection. If the vortex erosion continues and reaches to the hydraulic structure, it causes the deformation of the structure itself. To obtain the amount of the vortex erosion, it is necessary to determine the shear velocity of the line vortex in the scour hole was derived by the theory of energy conservation and found to be related to the upstream overflow velocity. The amount of vortex erosion from the scour hole was obtained using entrainment equation for given value of shear velocity. For a design purpose, if the flow velocity at the end of an apron and the properties of bed material are given, the amount of vortex erosion was obtained.

Keywords

References

  1. Akiyama, J., and Fukushima, Y. (1986). 'Entrainment of noncohesive bed sediment into suspension.' Proceedings 3rd International Symposium on River Sedimentation, pp. 804-813
  2. Asaeda, T., Nakai, M., Shyam, K. M., and Tamai, N. (1989). 'Sediment entrainment in channel with rippled bed.' Journal of Hydraulic Engineering, ASCE, Vol. 115, No. 3, pp. 327-339
  3. Engelund, D. M. and Fredsoe, E. A.(1985). 'Observations of rapidly flowing granular-fluid materials,' Journal of Fluid Mechanics, Vol. 143,pp. 357-380 https://doi.org/10.1017/S0022112085000167
  4. Ikeda, S., and Asaeda, T. (1983). 'Sediment suspension with rippled bed.' Journal of Hydraulic Engineering, ASCE, Vol. 109, No. 3,pp. 409-423
  5. Itakura, T., and Kishi, T. (1980). 'Open channel flow with suspended sediments.' Journal of Hydraulic Engineering, ASCE, Vol. 106, No. 8,pp. 1345-1352
  6. Kim, J. H. (1992). 'Experimental study on vortex characteristics at downstream part of hydraulic structure.' Journal of Agriultural Engineering, KSAE, vol. 34. pp. 151-163
  7. Kim, J. H. and Choe, J. W. (2000). 'Vortex structure in the scour hole by gate opening of hydraulic structure.' Water Engineering Research, Vol. 1, No. 1, pp. 83-92
  8. Kim, J. H. and Kim, J. S. (1999). 'Sheet erosion in embankment of noncohesive materials due to unsteady slow.' Journal of Civil Engineering, KSCE, Vol. 3, No. 1, pp. 59-69
  9. Savage, S. B.(1984). 'Gravity flow of cohesionless granular materials in chute and channels.' Journal of Fluid Mechanics, Vol. 142, pp. 53-66