• Journal of Korea Water Resources Association
• /
• v.30 no.6
• /
• pp.743-751
• /
• 1997

A thorough literatural review of researches on the experimental prediction of scour depths caused by jets was carried out to find out a measure of scour prediction. A new experimental equation for predicting scour depths due to a vortical or an inclined jet was developed from five hundreds of experimental data which were carefully reviewed and adopted from the previous researches. The developed equation shows 0.941 statistical correlation coefficient. It was found that the parameters governing the scour depth were the size of bed material, flow rate through unit width of spillway, and head drop across structure. The predicted scour depth could be expressed as the deepest scouring depth below tail water surface with correlation coefficient ${\gamma}$ = 0.941.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.13 no.4
• /
• pp.123-129
• /
• 1993

Because the existing scour prediction formulas for plunge pools of pipe culverts and spillways give a wide range of predicted scour depths, it is difficult to estimate actual scour depths. A review of literature showed that wide range of predicted values was caused mostly by lack of thorough analysis of the scour mechanism. In this study, the effects of the parameters govering scour were examined, and the scour potentials were measured. The major variables govering scour were the velocity and size of jet impinging into the plunge pool, the submerged weight of bed material, the ratio of jet size to bed material size, the tail watr depth of the plunge pool, and the angle of jet impact on water surface. The ratio of jet size to bed material size to bed material size was found to be another significant parameter affecting scour for larger bed materials. A densimetric Froude nember of the bed material in incipient motion was formulated. This number represented the scour potential of the jet at the point where the bed material was tested.

• Water Engineering Research
• /
• v.2 no.3
• /
• pp.179-185
• /
• 2001

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.