NUMERICAL SIMULATION OF SCOUR BY A WALL JET

  • A.A.Salehi Neyshabouri (Associate Professor, University of Tarbiat Modarres, Tehran, Iran) ;
  • R.Barron (Professor, Mathematics and Statistis, University of Windsor, Windsor, Ontaio, Canada) ;
  • A.M.Ferreira da Silva (Associate Professor, Civil Engineering, Queens University, Kingston, Ontario, Canada)
  • Published : 2001.07.01

Abstract

The time consuming and expensive nature of experimental research on scouring processes caused by flowing water makes it attractive to develop numerical tools for the predication of the interaction of the fluid flow and the movable bed. In this paper the numerical simulation of scour by a wall jet is presented. The flow is assumed to be two-dimensional, and the alluvium is cohesionless. The solution process, repeated at each time step, involves simulation of a turbulent wall jet flow, solution of the convection-diffusion of sand concentration, and prediction of the bed deformation. For simulation of the jet flow, the governing equations for momentum, mass balance and turbulent parameters are solved by the finite volume method. The SIMPLE scheme with momentum interpolation is used for pressure correction. The convection-diffusion equation is solved for sediment concentration. A boundary condition for concentration at the bed, which takes into account the effect of bed-load, is implemented. The time rate of deposition and scour at the bed is obtained by solving the continuity equation for sediment. The shape and position of the scour hole and deposition of the bed material downstream of the hole appear realistic.

Keywords

References

  1. Hoffman, G.J.C.M., and Booij, R. (1993) 'Two dimensional mathematical modeling of local scour holes,' Journal of Hydraulic Research, IAHR, Vol. 3, No. 5, pp. 615-634
  2. Lane, E. W., and Kalinske, A.A. (1941) 'Engineering calculations of suspended sediment,' Trans. Am. Geophys. Union, Vol. 22, pp. 603-607
  3. Olsen, N.R.B., and Melaaen, M.C. (1993) 'Three-dimensional calculation of scour around a cylinder,' Journal of Hydraulic Engineering, ASCE, Vol. 119, No. 9, pp. 1048-1053 https://doi.org/10.1061/(ASCE)0733-9429(1993)119:9(1048)
  4. Patankar, S.V. (1980) Numerical heat transfer and fluid flow, McGraw-Hill Book Company, New York, N.Y.
  5. Rhie, C.M., and Chow, W.L. (1983) 'Numerical study of the turbulent flow past an airfoil with trailing edge separation,' AIAA Journal, Vol. 21, No. 11, pp. 1525-1532
  6. Rodi, W. (1993) Turbulence models and their application in hydraulics. IAHR, Delft, the Netherlands
  7. Salehi Neyshabouri, A.A. (1988) Impingement of offset jets on rigid and movable beds. Ph.D. Thesis, University of Liverpool, Liverpool, England
  8. Ushijima, B., Shimitzu, T., Sakasi, A., and Takizawa, Y. (1992) 'Prediction method for local scour by warmed cooling water jets,' Journal of Hydraulic Engineering, Vol. 118, No. 8, pp. 1164-1183
  9. Ushijima, S. (1996) 'Arbitrary Lgrangian-Eulerian numerical prediction for local scour caused by turbulent flows,' Journal of Computational Physics, Vol. 125, pp. 71-82 https://doi.org/10.1006/jcph.1996.0080
  10. Van Rijn, L.C. (1987) Mathematial modeling of morphological processes in the case of suspended sediment transport. Ph.D. Thesis, Delft University of Technology, Delft, the Netherlands