EXPERIMENTAL STUDY ON THE SEDIMENT MOTION WITH TWO-PARTICLES OF THE SAME SIZE AND DIFFERENT SPECIFIC GRAVITY

Abstract

 Considering that all sediment originates from the riverbed, this study focuses on the concentration and velocity distributions of bed and suspended load to confirm the continuity of these distributions. Improvements in analytical techniques have made it possible to precisely track and count particles, and not only visualize vertical classification, but also directly calculate the volume of sediment from the concentration distribution. As a result, it was confirmed that suspended load and bed load have similar kinematic characteristics, moving at a high velocity in a downdraft, and the slight relationship of suspended load and bed load classifications was demonstrated once again. In addition, although the two particles were of the same size and no hiding occurred, a clear vertical classification was confirmed, and it became clear to what extent the sand feeding particles contribute to the exchange of the river bed. Furthermore, the experimental values of the concentration distribution and flow velocity allowed us to express the kinetic characteristics of the scouring particles on the riverbed surface in terms of the existence ratio of the particles.