Author(s): R. Narayanan; M. H. Omid
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Keywords: Bed load; Bed forms; Erosion; Rigid channel; Sediments
Abstract: The erosion of a layer of cohesionless sediments on the bed of a rigid rectangular channel exposed to the flow of clear water is of concern in this paper. Bed load is the only mode of transport studied. The process of removal of the sediments is studied both experimentally and numerically. The speed at which the layer of sediments moves downstream as it is eroded, is determined. The bed forms assumed by the sediments during the process of erosion have been observed. St. Venant’s equations and erosion equation for the bed of sediments are used as the governing equations with empirical input for the sediment discharge due to erosion. These equations are solved numerically by finite difference method using Lax explicit scheme. The speed of retreat of the toe of the sediment layer is computed and is compared with the experimental results. The bed forms and the water surface profiles are computed at various times and presented together with the experimental results. However the numerical procedure should include the continuity of sediment motion in greater detail if it is to predict the bed forms more accurately.
Year: 2005