Modeling bedload transport trajectories along a sine-generated channel

Authors: JIA, YAFEI - University Of Mississippi; ZHANG, YAOXIN - University Of Mississippi; CHEN, DONG - Chinese Academy Of Sciences; HE, LI - Chinese Academy Of Sciences; TERMINI, DONATELLA - University Of Palermo Italy

Submitted to: Water Resources Publication
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2019
Publication Date: 7/1/2019
Citation: Jia, Y., Zhang, Y., Chen, D., He, L., Termini, D. 2019. Modeling bedload transport trajectories along a sine-generated channel. Water Resources Publication. 46(4): 542-552. https://doi.org/10.1134/S0097807819040134.
DOI: https://doi.org/10.1134/S0097807819040134

Interpretive Summary: River sedimentation processes shape the direction and flow of rivers within the landscape. This paper reports a collaborative study of river sedimentation processes using physical experiments in China and a two-dimensional numerical model developed at the University of Mississippi. Physical observations demonstrated that there are two erosion regions in a channel bend that promotes lateral sediment transport in rivers, which is important for understanding river morphology. One region relates to the inside or convex portion of a channel where sediment does not cross the channel centerline and is important in shaping point bars. The other region is related to the pools of a bend where sediment becomes more complicated to describe. The numerical model results for the same experiment were consistent with observations from the experiments. Both the physical and numerical models enhanced our knowledge of sediment particle movement in meander river channels.

Technical Abstract: This study explores the influences of flow discharge and particle size on bedload transport trajec-tory by applying a depth-averaged two-dimensional model to a 110° sine-generated laboratory flume with wide-and-shallow sections. Calculated results exhibit two erosion regions in a bend: Zone-1-oreside of the point bar near the convex bank and Zone-2-near the apex of the concave bank. Sediments eroded from Zone-1 are mainly transported along the same-side convex bank rather than crossing the channel centerline, indicating the crucial role of longitudinal flow in shaping point bars. Most particles from Zone-2, however, behave more complicated by changing their trajectories with the developing bar-pool topography. Besides, sensitivity analyses indicate that, the shifting of bedload trajectory in the curved channel is not susceptible to particle size while considerably varies with flow discharge. Moving particles in a meandering channel are ultimately constrained within the belt of "concave bank-crossing bar-concave bank" after the bend topography is fully developed and the bed deformation reaches a dynamic equilibrium.