Author(s): Dawei Zhang; Jin Quan; Xiaoyan He; Xiaoming Jiang
Keywords: One-dimensional numerical model; Channel networks; Finite volume method; HLL scheme; Characteristic equations
Abstract: A novel numerical model for simulating open channel flows in river networks has been developed using Godunov method in order to avoid the problem that the traditional numerical models often fail when dealing with complex flow conditions. The model uses the HLL scheme to discretize Saint-Venant equations based on finite volume method and the numerical reconstruction technology is used to achieve second order accuracy in times and spaces. Junction flow conditions in the open channel networks are solved explicitly as the internal boundary conditions using the mass conservation, energy conservation and the characteristic equations. This algorithm does not require any specific node numbering method and the channels and junctions can be numbered randomly. Every junction and channel is treated independently in this model, therefore, this scheme can avoid solving the complex matrix occurred in implicit algorithm and is also suitable for programming on a parallel-processing computer. To demonstrate the potential of this model, its application to both single channel (including shock) and channel network problems (dendritic and circle river networks) is discussed. Numerical results compare well with analytical solutions or results computed by other numerical models.