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HYDRUS-3D是一个可用来模拟土壤水流及溶质三维运动的有限元计算机模型。程序可以灵活处理各类水流边界,包括定水头和变水头边界、给定流量边界、渗水边界、大气边界以及排水沟等。水流区域本身可以是不规则水流边界,甚至还可以由各向异性的非均质土壤组成。本文介绍了HYDRUS-3D这一最新成果数学模型构成,并利用这一模型软件模拟计算了土壤水流及溶质的三维运动,水流控制方程采用修改过的Richards方程,对水流区域进行不规则三角形网格剖分,控制方程采用伽辽金线状有限元法进行求解,得到了水分和溶质在土壤中随时间的变化关系,可以提供从0.00001到5,近6个数量级的事件时间分辨率精度。其实际应用结果表明,HYDRUS-3D不仅功能齐全,能够提供强大的模型计算能力,并且其生成的模型能真实地反映水分和溶质入渗过程,可被应用于土壤含水量的前期预报工作。
HYDRUS-3D is a finite element computer model that can be used to simulate soil water flow and solute 3D motion. The program can flexibly handle all types of flow boundaries, including fixed and variable head boundaries, given flow boundaries, seepage boundaries, atmospheric boundaries, and drains. The water flow area can itself be an irregular water flow boundary and can even consist of anisotropic, heterogeneous soils. In this paper, HYDRUS-3D, a mathematical model of the latest achievements, is introduced. By using this model software to simulate the three-dimensional movement of soil water and solute, the water flow control equation adopts the modified Richards equation to carry out the irregular triangular grid The subdivision and control equations are solved by the Galerkin linear finite element method. The relationship between moisture and solute in soil over time is obtained, and the accuracy of event time resolution from 0.00001 to 5 and nearly 6 orders of magnitude can be provided. The practical application shows that HYDRUS-3D is not only fully functional but also capable of providing powerful model calculation capability. The generated model can truly reflect the process of water and solute infiltration and can be applied to the prediction of soil moisture content.