Author(s): Dong Chen; Li He
Linked Author(s): Dong Chen, Li He
Keywords: Bed armoring; Bed-load; Experiment; Flume; Anomalous dispersion
Abstract: This study investigates the time evolution of a bed armoring process by conducting a flume study with mixed-size sand/gravel. Mixture of five size categories (0. 23mm, 1mm, 3mm, 7mm, and 10mm) is well-mixed and carefully paved, setting an initial slope in the flume. Constant inflow is designed to be able to transport all but the coarsest particles (10mm in diameter) from the bed surface. No sediment is fed from upstream in the study, which results in a static armoring. Fractional transport rates as the armor layer develops are measured with time by sediment trapping method at the end of the flume. Coupled observations of flow and transport cast doubt on the traditional hypothesis of exposure and hiding factors which play a key role in modeling non-uniform sediment transport. New models are necessary to predict the anomalous dispersion of bed-load on a heterogeneous bed surface created by a static armor layer.
Year: 2013