Self-simility Of River And Theoretical Analysis Of Sediment Movement

The simulation of the water and sediment process in the watershed especially to the big scale watershed can be perfectly completed by the digital watershed model. It plays an important role in the flood controlling and water regulating. The river network in the digital watershed model is detailedly researched to optimize and consummate the model from the view of basic theory. The operation method of extracting river network is list out and applied to the specific examples. The distinctness between the various classification and codification to river network is discussed to know the structure of the network better. A platform is constructed based on the digital watershed model codification to extract the parameter from the river network. The data needed in the river network morphology is directly gotten from the plat.The morphology of the river network is discussed by the method of self-similarity and fractal theory. A generator sequence is formed to character the morphology of the river network. A self-similar river network, which is plane-filling, is constructed. A new fractal dimension and morphological parater are generated accordingly.The movement of the sediment particle is classified into the two-phase flow. The mathematical expression of the particle motion state is the nonlinear Boltzmann equation with differential and integral terms in the view of the kinetic theory. Homotopy analysis method is a new and efficient way to nonlinear problems. The Maxwell velocity distribution function is chosen as the initial conjecture solution in the Boltzmann equation of dilute granular flow. The concrete expression of the first-order approximate solution to the Boltzmann equation with collision term being BGK model, which is consistent to the solution by traditional method, is given. The homotopy analysis method promotes the development of the Boltzmann equation. It is a successful application of homotopy analysis method and the base of solving more general nonlinear problems of fluid dynamics.