非饱和土中溶混污染物运移模型及特征线有限元法

提出了一个非饱和土中溶混污染物输运过程的数值模拟框架。输运过程数学模型包含了包括物理和化学非平衡过程的如下控制现象:对流,机械逸散,分子弥散,平衡与非平衡吸附,不流动水效应和蜕变。发展了基于特征线Galerkin 离散化的有限元方法和相应的隐式算法以数值求解模型控制方程的边值初值问题。隐式算法基于算子分离过程及在Lagrange 座标下精细积分过程与传统数值积分过程的结合。数值例题结果和稳定性分析验证了本文模型及其数值方法的有效性,计算精度和稳定性

Miscible pollutant transport model for unsaturated soils and characteristic finite element method

A framework for numerical modelling of miscible pollutant transport in saturated unsaturated soils is presented. The mathematical model of the transport process integrates the following governing phenomena: convection, molecular diffusion, mechanical dispersion, sorption, immobile water effect and degradation, including both physical and chemical nonequilibrium processes. A finite element method based on the characteristic Galerkin discretization is developed. A corresponding implicit algorithm is devised to numerically solve the initial and boundary value problem for the model governing equations. The implicit algorithm is based on the operator splitting procedure and formulated by means of a combination of both the precise and the traditional numerical integration procedures in the Lagrange coordinates. The numerical results and the stability analysis of the algorithm validate good performance of the present model and efficiency, accuracy and stability of the present numerical method.