关键词: 二维输运问题, 计算方法, 溶质浓度, 差分方程, 特征线法, 弥散系数, 对流项, 地下水污染, 化学剂, 数学模型

Abstract: A two-dimensional transport equation describing the dispersion and adsorption of chemicals in a solution flowing through a porous medium can be solved numerically by the method of characteristics conbined with the method of finite difference. The characteristics technique is used firstly to obtain the concentration field generated by the convection term, this concentration is called "convection concentration";secondly the method of finite difference is used to obtained the concentration field generated by the dispersion as well as other terms, taking the convection concentration as a known, this concentration is then called "dispersion concentration". Finally, the total concentration in a given time step is yielded by adding the above two concentrations. The effects of dispersion and adsorption on the concentration of the solute are investigated by choosing different parameters in this twodimensional model. The results show that the numerical method introduced in our paper is applicable. The solutions obtained are valuable in many fields of practical interests, such as surfactant, and polymer flooding in enhanced oil recovery operations, the pollution of ground water and other problems.