Models for Ground Water Flow: A Numerical Comparison Between Richards' Model and the Fractional Flow Model
Models for Ground Water Flow: A Numerical Comparison Between Richards' Model and the Fractional Flow Model
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地下水流模型：Richards 模型与分数流模型的数值比较
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
C. Tegnander
中科院分区：
文献类型：
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作者：
C. Tegnander
在本文中，我们比较了多孔介质中流动的两种模型。第一个是众所周知的理查兹方程，该方程基于非饱和区空气具有无限流动性的假设。这意味着它模拟单相。在第二种也是更一般的全两相方法中，空气被视为单独的相。在这里，我们使用分数流方程。我们通过改变分数流方程中不同物理项（重力和总速度）的相对贡献来数值研究两个模型之间的差异。当气相的流动性趋于无穷大时，理查兹方程被认为是分数流方法的极限。特别是，我们有兴趣确定两个模型显着不同的参数区间，并且我们将量化渐近行为。在二维 (2D) 情况下研究方程。该研究基于与饱和度成二次关系的相对渗透率以及由饱和度的三次函数表示的毛细管压力。
In this paper we compare two models for flow in porous media. The first is the well known Richards' equation, which is based on the assumption that the air in the unsaturated zone has infinite mobility. This means that it models a single phase. In the second and more general full two-phase approach, the air is considered as a separate phase. Here, we use the fractional flow equation.We study the difference between the two models numerically by varying the relative contribution of the different physical terms (the gravity and the total velocity) in the fractional flow equation. Richards' equation is considered as the limit of the fractional flow approach when the mobility of the air-phase tends to infinity. In particular, we are interested in determining the parameter intervals where the two models differ significantly, and we will quantify the asymptotic behavior.The equations are studied in the two-dimensional (2D) case. The study is based on a relative permeability depending quadratically on the saturation, and a capillary pressure expressed by a cubic function of the saturation.