Two-dimensional Hydrodynamic Model for Complex Channel Networks

Owing to complex and irregular bottom topography and the large longitudinal scale, the hydrodynamic simulation of river networks is often dealt as one-dimensional problems in examinations of river-lake systems. Traditional two-dimensional models, which contain the bottom topography (depth) information of just one point in an element, couldn't escape the conflict between computational effort and simulation precision when being applied to river networks: refined grids causes huge computational amount and harsh limits to algorithms, while course girds could not represent the bottom irregularities, resulting in a low precision. Here, a new two-dimensional model based on improved shallow flow equations, which consider the bottom topography, is developed to cope with river networks domain. Owing to the topography information of multiple points is considered in one element, the proposed model could get a satisfying result with a coarse mesh. The new 2D model for river networks is tested by a virtual example and resolving the Sanya River network. Numerical simulations show that the model can be a useful tool for complex river networks problems.