EFFECT OF WALL SHEAR ON PARTICLE MOTION IN SEDIMENT LADEN OPEN CHANNEL FLOW

Abstract

The paper deals with the concentration distributions of sediment particles in turbulent rectangular open channel flow. Special attention is paid on the effect of channel wall shear on the concentration profiles of sediment particles. Using the Reynolds strecc model, a mathematical model to describe the fluid and sic: din-mut motion in a prismatic open channel was presented. After confirming the validity of this model by laboratory experiments, sediment motions in a lateral cross section were discussed by this model. It was shown that the sediment particles flow downward with circularity trajectories like secondary current of fluid motion. Due to the settling of the sediment particles, the location of the center of the trajectory is somewhat near to the sidewall and to the bottom, compared with that of fluid motion. Experiments on sediment laden open channel flow, reported so far, were also reproduced numerically. In some cases of the reported paper, it was found that the circulatory motion of sediments spread almost over cross section. To the case of compound channels, the effect of relative height of the flood plane on sediment distributions were also investigated.