Study On Three-Dimensional Multi-Level Hydrodynamic Model With Curvature Correction In Curvilinear Coordinates

Environmental pollution and protection is one of the big problems in the world. With the development of industry, a large amount of industry waste water and life polluted water harmful to people and other living things is discharged into river, lake, reservoir and ocean and make the natural water much more polluted. To protect environment, people must study the hydrodynamic and pollutant transport characteristics to obtain the distribution of the concentration.In this paper, a three-dimensional multi-level hydrodynamic model with curvature correction in curvilinear coordinates has been developed based on the update turbulent theory and numerical method, which can effectively solve the practical problems of flows and water quality transportations in hydraulic engineering, and can strengthen the practical usage of the mathematical model. The research also has theoretical meanings and practical values in engineering.The research details and results of this paper are as follows:1.The purpose and meanings of the research has been discussed; the development of numerical simulation for flows and matter transportations have been analyzed and commenced, and the problem to be solved has been presented; the update turbulent theory , numerical method and the key techniques in turbulence numerical simulation( such as the discretization method, the method of determining free water surface, and treatment of complicated boundary, etc.) have been summarized.2.A three-dimensional multi-level hydrodynamic model in Cartisn coordinates has been developed, and is solved numerically with a finite-volume method on an adaptive, nonstaggered grid.Comparisons between computed results and measured data in a straight open channel flow show that the multi-level hydrodynamic model with the standard layer averaged k-εturbulence model is capable of simulating turbulence flow, both the mean flow and the turbulence quantities. The water depth correction scheme can be used to obtain the free-surface elevation, avoiding the rigid-lid assumptions, and eliminating the oscillation of the calculations due to the non-staggered grid arrangement. 3.A new method for the generation of curvilinear grid has been proposed. Some curvilinear grid generation examples show that satisfactory grids can be generated for simple-connected regions and connected- regions with complex boundary by using the proposed adjusting factors. The curvilinear grid at boundaries is orthogonal and the interior grids can be adaptive to the variation of physical parameters of fluid.4.A three-dimensional multi-level hydrodynamic model in curvilinear coordinates has been developed based on the proposed curvilinear grid generation method. The use of the curvilinear coordinates and non-staggered grid system increases the ability of the present model in computing complex 3D flows,5.To increases the ability of the present model in computing complex 3D free surface flows in channel bands, the three-dimensional multi-level hydrodynamic model in curvilinear coordinates including effects of significant curvature has been developed.