Investigation on Incipient Deposition and Incipient Motion of Sediment Particles in Rigid Boundary Channels

Rigid boundary channels are widely used as water conveyors in surface drainage، sewers and other systems. In order to do optimum and economic design، consideration of the movement of sediment particles is quite important. In this research، experimental data of incipient deposition and incipient motion of sediment particles are used. Applying critical velocity approach، new equations for incipient deposition of sediment particles in rigid boundary channels having circular، rectangular and U-shaped cross sections and also a new incipient motion equation for a V-shaped cross section are presented. These equations are compared with available equations given by critical velocity approach for incipient motion of sediment particles in rigid and loose boundary channels. The present research reveals the difference between incipient deposition and incipient motion، indeed. Herein، the effect of cross sectional shape on incipient deposition and incipient motion of sediment particles in rigid boundary channels are also considered. Analysis of the results using the estabilished equations for incipient deposition of the sediment particles in channels with different cross section shapes shows that rectangular channels require a lower critical velocity and U-shaped channels need a higher amount. This result clearly states the effect of cross sectional shape on incipient deposition for sediment particles in rigid boundary channels. Because of the lack of available data، the present analysis can be usefull for developing numerical models in rigid boundary channels.