Laboratory Study of Transport of Fine Sand

Laboratory tests were conducted to define the relationships between the transport of fine sand and the flow variables. Data from 105 experiments with sand bed material having a median sieve diameter of 0.1 mm in a 100-ft (30.48 m)-long by 4-ft (1.22 m)-wide recirculating flume show that the concentration of the transported material depends in a rather complex, but consistent way on the basic flow variables. A graphical relationship between the concentration and the flow discharge per unit of channel width defines consistent curves of equal depth and readily delineates the various bed form regimes. A similitude analysis of published transport data for coarser sands suggests a single curve for concentration versus Froude number for each median sediment size. However, the data for the 0.1-mm material suggest separate curves of concentration versus Froude number for the different bed form regimes. The data for depths less than or equal to 0.7 ft (0.21 m) define a continuous relationship like that for coarser sands, but the data for deeper depths define an extended plane bed curve segment that has not been observed for coarser material.