特征线和匹配人工弥散系数联合法求解地下水中的溶质运移问题

Characteristic and Matched Artificial Dispersion Combined Method for Solving Solute Travel in Groundwater

本文先把二维对流－弥散方程分解为横向一维对流－弥散方程和纵向一维纯弥散方程的组合。对于前者联合使用特征线法或匹配人工弥散系数法求解；而对于后者则用普通的差分法求解。两者再通过交替方向法联结，以完成某个时段的计算。最后把联合法应用于一维和二维溶质运移模拟，并与其它方法比较。

A 2-D advection-dispersion equation is split into a transverse 1-D advection-dispersion equation and a longitudinal 1-D pure dispersion equation. The former is solved by the characteristic finite difference method(when P_e<2) or by the matched artificial dispersion method (when P_e>2), and the latter is solved by common difference method. Then both equations are linked by the alternating direction scheme to complete the computation of a certain period.Finally,the combined method is applied to 1-D and 2-D solute travel simulation to compare with analytical solutions and solutions acquired by other methods. The results show that the combined method has high accuracy accompanied with small numerical dispersion and oscillation.