Sediment Pick-Up Function for High Velocities: Experimental Evaluation

In three papers Bakker and Van Kesteren developed a theory concerning grain-grain interaction, "zipper consolidation" and "zip-erosion". As practical result of their investigations a pick-up function was proposed for the case of stationary uniform erosion in slightly non-uniform and slightly non-steady vigorous flow (mean velocity of the order of 1 to 10 m/s). In the theory, especially the effect of viscosity of the fluid, in which the grains are immersed is incorporated: the effect of grain diameter on scour should emanate from this. In the present paper the theory is evaluated. Extending research of Visser, former breach erosion tests are re-considered. Furthermore, special tests carried out in the Laboratory for Fluid Mechanics of the Delft University of Technology are analyzed. In an appendix, the theory itself is explained in more detail than before.