Numerical modeling of toxic nonaqueous phase liquid removal from contaminated groundwater systems: mesh effect and discretization error estimation
Numerical modeling of toxic nonaqueous phase liquid removal from contaminated groundwater systems: mesh effect and discretization error estimation
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从受污染地下水系统中去除有毒非水相液体的数值模拟：网格效应和离散误差估计
DOI：
10.1002/nag.2327
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发表时间：
2015-04
影响因子：
4
通讯作者：
Regenauer-Lieb, Klaus
中科院分区：
文献类型：
--
作者：
Zhao, Chongbin;Poulet, Thomas;Regenauer-Lieb, Klaus
数值模拟已成为研究污染地下水系统中有毒非水相液体（NAPL）去除基本机理的重要工具。由于受污染地下水系统的区域可能涉及不规则的几何形状，因此有必要使用一般的四边形单元，其中相邻的两个边不再相互垂直。由于网格离散效应，计算模拟结果会出现数值误差。在简要描述了NAPL溶解问题的无量纲控制方程的基础上，提出了与NAPL溶解系统相关的网格离散化误差在矩形域的传播理论，并将其推广到梯形域。这导致了指幅增长理论的建立，该理论与发生在梯形区域流动入口处的角效应和发生在梯形区域整个NAPL溶解系统中的网格离散效应有关。该理论可用于对相应的计算仿真结果进行近似误差估计。相关的理论分析和数值结果表明：(1)角效应和网格离散化效应都可以定量地看作是一种小的扰动，在不稳定的NAPL溶解体系中，角效应和网格离散化效应会增长，从而对系统的计算结果产生相当大的影响；(2)提出的与梯形域入口角效应相关的手指振幅增长理论有助于正确解释为什么手指在顶部或底部边界的增长速度远快于梯形域内部的增长速度；(3)提出的与梯形域NAPL溶解体系网格离散误差相关的指幅增长理论可用于定量评估梯形域NAPL溶解前沿不稳定问题计算模拟的正确性，从而确保计算模拟结果受NAPL溶解体系的物理特性控制，而不是受数值伪影控制。版权所有©2014 John Wiley & Sons， Ltd。
Numerical modeling has now become an indispensable tool for investigating the fundamental mechanisms of toxic nonaqueous phase liquid (NAPL) removal from contaminated groundwater systems. Because the domain of a contaminated groundwater system may involve irregular shapes in geometry, it is necessary to use general quadrilateral elements, in which two neighbor sides are no longer perpendicular to each other. This can cause numerical errors on the computational simulation results due to mesh discretization effect. After the dimensionless governing equations of NAPL dissolution problems are briefly described, the propagation theory of the mesh discretization error associated with a NAPL dissolution system is first presented for a rectangular domain and then extended to a trapezoidal domain. This leads to the establishment of the finger‐amplitude growing theory that is associated with both the corner effect that takes place just at the entrance of the flow in a trapezoidal domain and the mesh discretization effect that occurs in the whole NAPL dissolution system of the trapezoidal domain. This theory can be used to make the approximate error estimation of the corresponding computational simulation results. The related theoretical analysis and numerical results have demonstrated the following: (1) both the corner effect and the mesh discretization effect can be quantitatively viewed as a kind of small perturbation, which can grow in unstable NAPL dissolution systems, so that they can have some considerable effects on the computational results of such systems; (2) the proposed finger‐amplitude growing theory associated with the corner effect at the entrance of a trapezoidal domain is useful for correctly explaining why the finger at either the top or bottom boundary grows much faster than that within the interior of the trapezoidal domain; (3) the proposed finger‐amplitude growing theory associated with the mesh discretization error in the NAPL dissolution system of a trapezoidal domain can be used for quantitatively assessing the correctness of computational simulations of NAPL dissolution front instability problems in trapezoidal domains, so that we can ensure that the computational simulation results are controlled by the physics of the NAPL dissolution system, rather than by the numerical artifacts. Copyright © 2014 John Wiley & Sons, Ltd.
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影响因子：
1.7
作者：
Chong-bin Zhao;B. Hobbs;A. Ord;P. Hornby;S. Peng
通讯作者：
Chong-bin Zhao;B. Hobbs;A. Ord;P. Hornby;S. Peng
DOI：
10.1002/nag.880
发表时间：
2010-12
影响因子：
4
作者：
Chong-bin Zhao;B. Hobbs;A. Ord
通讯作者：
Chong-bin Zhao;B. Hobbs;A. Ord
DOI：
10.5860/choice.35-0927
发表时间：
1984-05
期刊：
--
影响因子：
--
作者：
L. Cussler
通讯作者：
L. Cussler
影响因子：
7.4
作者：
E. C. Childs
通讯作者：
E. C. Childs
影响因子：
4.6
作者：
TAN, CT;HOMSY, GM
通讯作者：
HOMSY, GM