A boundary integral method for steady unsaturated flow in nonhomogeneous media
A boundary integral equation method for steady unsaturated flow in nonhomogeneous porous media is presented. Steady unsaturated flow in porous media is described by the steady form of the so-called Richards equation, a highly nonlinear Fokker-Planck equation. By applying a Kirchhoff transformation and employing an exponential model for the relation between capillary pressure and hydraulic conductivity, the flow equation is rendered linear in each subdomain of a piece-wise homogeneous material. Unfortunately, the transformation results in nonlinear conditions along material interfaces, giving rise to a jump in the potential along these boundaries. An algorithm developed to solve the nonhomogeneous flow problem is described and verified by comparison to analytical and numerical solutions. The code is applied to examine the moisture distribution in a layered porous medium due to infiltration from a strip source, a model for infiltration from shallow ponds and washes in arid regions.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5657426
- Report Number(s):
- SAND-91-2555C; CONF-920664-1; ON: DE92009066
- Resource Relation:
- Conference: 7. international conference on boundary element technology, Albuquerque, NM (United States), 3-5 Jun 1992
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
STEADY FLOW
BOUNDARY ELEMENT METHOD
ALGORITHMS
BOUNDARY-VALUE PROBLEMS
FOKKER-PLANCK EQUATION
INTEGRAL EQUATIONS
POROUS MATERIALS
QUASILINEAR PROBLEMS
DIFFERENTIAL EQUATIONS
EQUATIONS
FINITE ELEMENT METHOD
FLUID FLOW
MATERIALS
MATHEMATICAL LOGIC
NUMERICAL SOLUTION
PARTIAL DIFFERENTIAL EQUATIONS
665000* - Physics of Condensed Matter- (1992-)
990200 - Mathematics & Computers