Premium
Application of Second‐Type Boundaries in Unsaturated Flow Modeling
Author(s) -
McCord J. T.
Publication year - 1991
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/91wr02158
Subject(s) - boundary (topology) , boundary conditions in cfd , boundary value problem , type (biology) , flow (mathematics) , different types of boundary conditions in fluid dynamics , mathematics , no slip condition , mixed boundary condition , computer science , robin boundary condition , mathematical analysis , geometry , geology , paleontology
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.