Numerical Study of Sediment Transport with Flow Hydrographs of Varying Length in a Laboratory Flume

Abstract

Abstract This paper presents a numerical sediment transport model based on data from a series of experiments with flow hydrographs of varying lengths in a laboratory flume with a sand bed. The model was calibrated and validated using one flow hydrograph and then applied to other hydrographs. Digital flumes with different initial and boundary conditions were generated to assist numerical simulations and further explore additional scenarios, such as flow rates on the rising limb of the hydrograph, different sediment sizes, and longer hydrographs. Both numerical and experimental results demonstrate the influence of flow hydrograph duration on transport rates, which typically resulted in a counterclockwise hysteresis pattern. Different rising slopes of the flow rate had limited effects on the hysteresis pattern. Coarser sediment yielded lower transport rates, while finer particles led to increased transport rates, though neither caused appreciable changes to the hysteresis pattern. Limited sediment supply resulted in a change in hysteresis pattern from counterclockwise to figure-8. Longer hydrographs led to irregular hysteresis patterns due to the influence of bedforms that developed during peak flows.