Numerical simulation of meandering evolution

A two-dimensional depth-averaged hydrodynamic model is developed to simulate the evolution of meandering channels from the complex interaction between downstream and secondary flows, bed load and suspended sediment transport, and bank erosion. The depth-averaged model calculates both bed load and suspended load assuming equilibrium sediment transport and simulates bank erosion with a combination of two interactive processes: basal erosion and bank failure. The mass conservation equation is solved to account for both vertical bed-elevation changes as well as lateral migration changes when sediment is removed through basal erosion and bank failure. The numerical model uses deformable elements and a movable grid to simulate the gradual evolution of a near-straight deformable channel into a highly sinuous meandering channel. The model correctly replicates the different phases of the evolution of free meandering channels in experimental laboratory settings including: (1) downstream and upstream migration; (2) lateral extension; and (3) rotation of meander bends.