Regional Quasi-Three-Dimensional Unsaturated-Saturated Water Flow Model Based on a Vertical-Horizontal Splitting Concept
Regional Quasi-Three-Dimensional Unsaturated-Saturated Water Flow Model Based on a Vertical-Horizontal Splitting Concept
复制标题
基于纵横分裂概念的区域准三维非饱和-饱和水流模型
DOI：
10.3390/w8050195
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发表时间：
2016
期刊：
影响因子：
3.4
通讯作者：
Yang Jinzhong
中科院分区：
文献类型：
--
作者：
Zhu Yan;Shi Liangsheng;Wu Jingwei;Ye Ming;Cui Lihong;Yang Jinzhong
由于三维（3-D）非饱和-饱和水流方程的高度非线性，对于大规模应用，使用全3-D数值模型在计算上昂贵。本文基于垂直/水平分裂（VHS）概念，将三维非饱和-饱和理查兹方程分裂为二维水平方程和一维垂直方程，建立了一种新的非饱和-饱和水流模型。推导了三棱柱单元中水头平均梯度的水平面，将三维方程分解为二维方程。然后用水量平衡法计算了平均水头比降水平面内的侧向流。采用有限差分法对一维垂向方程进行离散。这两个方程通过耦合成一个统一的非线性系统与一个单一的矩阵同时求解。通过与Hydrus 1D、SWMS 2D和FEFLOW的模拟结果进行比较，对所开发的模型程序进行了三个合成案例的评估。进一步将该模型应用于区域尺度地下水位波动模拟，以评估该模型在复杂条件下的适用性。所提出的建模方法被认为是准确的测量。
Due to the high nonlinearity of the three-dimensional (3-D) unsaturated-saturated water flow equation, using a fully 3-D numerical model is computationally expensive for large scale applications. A new unsaturated-saturated water flow model is developed in this paper based on the vertical/horizontal splitting (VHS) concept to split the 3-D unsaturated-saturated Richards’ equation into a two-dimensional (2-D) horizontal equation and a one-dimensional (1-D) vertical equation. The horizontal plane of average head gradient in the triangular prism element is derived to split the 3-D equation into the 2-D equation. The lateral flow in the horizontal plane of average head gradient represented by the 2-D equation is then calculated by the water balance method. The 1-D vertical equation is discretized by the finite difference method. The two equations are solved simultaneously by coupling them into a unified nonlinear system with a single matrix. Three synthetic cases are used to evaluate the developed model code by comparing the modeling results with those of Hydrus1D, SWMS2D and FEFLOW. We further apply the model to regional-scale modeling to simulate groundwater table fluctuations for assessing the model applicability in complex conditions. The proposed modeling method is found to be accurate with respect to measurements.