Numerical Simulation of Meandering Evolution

Evolution of meandering channels, a complex morpho-dynamic process, has been the focus of research challenging geomorphologists and river engineers for decades. The evolution of meandering channel is a result of the complex interactions between flow, sediment transport, and bank erosion. A numerical model including a depth-averaged two-dimensional hydrodynamic flow model, a sediment transport model, and a bank erosion model was developed to simulate the evolution of a low sinuous meandering channel into a high sinuous one. The sediment transport model calculates both bed load and suspended load assuming equilibrium sediment transport. Bank erosion simulation consists of two interactive processes: basal erosion and bank failure. The mass conservation equation where sediment from basal erosion and bank failure is considered as a source term, was solved to obtain the rate of bank erosion. Then, this model was applied to simulate the evolution of free meandering channels in laboratory experimental settings. The model successfully replicated the evolution processes of meandering channel from downstream translation, lateral extension, and then follows by upstream and downstream rotation when sinuosity approaches 3.7. Plots of meandering planforms illustrate the capabilities of numerical model in simulating the evolutions of meandering planform (e.g. downstream translation, lateral extension, upstream and downstream rotation).