Laboratory measurements of vortex-induced sediment pickup rates

In the present study,vortices were generated in open channel flow with a cross-flow cylinder installed horizontally near the bed.Sediment pickup rates were then measured over the channel bed downstream the cylinder using a sediment lift.The experimental data show that the pickup rate increases exponentially in the presence of vortices.Two different relationships can be clearly observed between the pickup rate and the maximum root-mean-square (rms) value of the streamwise velocity fluctuation,one for the cylinder-obstructed flow and the other for the unobstructed flow.The results imply that the vortex-induced sediment pickup cannot be explained based on the traditional boundary layer theory.