Numerical Simulation Of 2D Groundwater Flow And Water Quality In Curvilinear Coordinate System

Groundwater contamination is an important problem in environmental science research, and numerical simulation is a powerful tool for groundwater pollutants transport research. In this paper, a curvilinear gird being approximate orthogonal near the boundary has been obtained by using a proposed boundary-fitted coordinate technology; and two-dimensional groundwater seepage model and pollutant transportation model in the curvilinear coordinate system have been generated. The research details of this paper are as follows:(1) Aiming at some problems concerning the adjusting functions in the commonly used Thompson and Thomas methods in the generation of curvilinear grid, a new adjusting function is proposed, by which the curvilinear gird being approximate orthogonal near the boundary can be generated, and some curvilinear grid generation examples show that by using the proposed adjusting factors ideal grids can be generated for simple-connected regions and multi-connected regions with complex boundary.(2) The governing equations are transformed from physical plane (x,y coordinate system) to computational plane (ξ ,η curvilinear coordinate system) used boundary-fitted coordinate technology, and the governing equations under orthogonal curvilinear coordinates system are discriminated and solved. The pollutant transportation governing equations have been solved by the alternating-direction-implicit technique (ADI), and upwind scheme is used about in the course of discrimination equations.(3) Comparing the computational results in curvilinear coordinate system with theoretical results, we find that they coincide well.(4)At last, the dynamics model with varying coefficients for the chemical transport is developed through the study on the mechanism of pollutant transport in groundwater. The analytical solution is obtained based on the mathematical , and the physical methods and the sensitivities for the parameters used in the model are analyzed.The research results in this paper can provide a reference for the solution to practicalproblems in environmental engineering.