Application of Second‐Type Boundaries in Unsaturated Flow Modeling
Application of Second‐Type Boundaries in Unsaturated Flow Modeling
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DOI：
10.1029/91wr02158
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发表时间：
1991-12
影响因子：
5.4
通讯作者：
J. T. McCord
中科院分区：
文献类型：
--
作者：
J. T. McCord
在涉及非饱和流的数值模拟中，通常采用指定水头和/或指定流量作为边界条件。一些建模者错误地将指定的通量条件称为第二类边界。在数学文献中，第二类边界被定义为因变量的梯度沿其沿着被指定的边界。本说明确定了第二类边界（指定梯度）可能是最合适的边界条件的物理场景，讨论了在流动代码中实现指定梯度边界条件的过程，并提出了该过程在两个实际问题的模拟中的应用。
Specified head and/or specified flux are typically employed as boundary conditions in numerical simulations involving unsaturated flow. Some modelers incorrectly refer to a specified flux condition as a second-type boundary. In the mathematical literature a second-type boundary is defined as a boundary along which the gradient of the dependent variable is specified. This note identifies physical scenarios in which a second-type boundary (specified gradient) may be the most appropriate boundary condition, discusses a procedure for implementing a specified gradient boundary condition in a flow code, and presents an application of the procedure in the simulation of two practical problems.