Influence of Suspended Load on 3D NumericalSimulation of Flow and Bed Evolutionin a Meandering Channel Bend

摘要

A three-dimensional (3D) numerical model based on unstructured grids has been used to study flow and bed evolution in a laboratory meandering channel bend. The model employs the Reynolds-averaged Navier-Stokes equations and the low-Reynolds-number k — ωturbulence model for flow simulation. The model incorporates the suspended-load transport module and the bed-load transport module to simulate sediment transport and employs the sediment continuity equation to calculate channel bed evolution. The numerical simulation is performed in a meandering channel with a movable bed, in which the suspended load is comparable to the bed load. The model captures the main features of the bathymetry at equilibrium conditions. The streamwise velocity profiles and the suspended sediment concentration profiles at equilibrium conditions are also predicted by this simulation, and the agreement with the measured data is generally reasonable. The influence of including the suspended load is revealed by the comparison between the results obtained with total-load model and bed-load model in the meandering channel.