Experimental Analysis of Incipient Motion for Uniform and Graded Sediments

So far, few studies have focused on the concept of critical flow velocity rather than bed shear stress for incipient sediment motion. Moreover, mixtures (graded sediment) and shape uniform motion condition. Different experiments were conducted at a hydraulic laboratory University Guilan in 2015 to determine parameters The aim this study is conduct comparison between graded sediments, round angular sediments. Experiments included rounded sediments 5.17, 10.35, 14 20.7 mm, 10.35 sediment. Results demonstrated that has higher also showed given sediment, although shield relative roughness increased with slope, particle Froude number (based velocity) decreased. In terms mixture, (Vc*) was three finer sizes. fractions mixture their corresponding value, while coarser lower stability value. reduction more evident conditions. current provides clearer insight into interaction initial transport characteristic, especially natural rivers where stream beds different gravel size distribution.