Study of the conditions of incipient motion of non cohesive sediment in open channel flow with rectangular section and milled slop

Deposition of sediment inside the conduit structures reduces the flow cross section area and increase the flow roughness which causes reduction of flow discharge passing through the conduit. Among the methods in which can be achieved such goals is to design the structure in such a way that the flow velocity to be greater than incipient motion velocity. A lot of work has been recently done to determine the conditions of incipient motion velocity in bed with usual and deep slope. All of these studies have been done on natural sediment with 2. 65 densities. This research studies conditions of incipient motion velocity in open channel flow with rectangular section by using physical modeling and dimensional analysis. In this study 12 non-sticky sediment specimens with different dimensions and density in. 5%، 1% and 1٫5% slope have been tested. One graph was drown that can be used for determining of incipient motion in open channel and rectangular section; the findings of this study were also compared with other experimental relation.