T2CG1, a package of preconditioned conjugate gradient solvers for TOUGH2
- Lawrence Berkeley Lab., CA (United States). Earth Sciences Div.
Most of the computational work in the numerical simulation of fluid and heat flows in permeable media arises in the solution of large systems of linear equations. The simplest technique for solving such equations is by direct methods. However, because of large storage requirements and accumulation of roundoff errors, the application of direct solution techniques is limited, depending on matrix bandwidth, to systems of a few hundred to at most a few thousand simultaneous equations. T2CG1, a package of preconditioned conjugate gradient solvers, has been added to TOUGH2 to complement its direct solver and significantly increase the size of problems tractable on PCs. T2CG1 includes three different solvers: a Bi-Conjugate Gradient (BCG) solver, a Bi-Conjugate Gradient Squared (BCGS) solver, and a Generalized Minimum Residual (GMRES) solver. Results from six test problems with up to 30,000 equations show that T2CG1 (1) is significantly (and invariably) faster and requires far less memory than the MA28 direct solver, (2) it makes possible the solution of very large three-dimensional problems on PCs, and (3) that the BCGS solver is the fastest of the three in the tested problems. Sample problems are presented related to heat and fluid flow at Yucca Mountain and WIPP, environmental remediation by the Thermal Enhanced Vapor Extraction System, and geothermal resources.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 145291
- Report Number(s):
- LBL-35518; ON: DE94015159; TRN: 94:013765
- Resource Relation:
- Other Information: PBD: Mar 1994
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COMPUTERS
INFORMATION SCIENCE
MANAGEMENT
LAW
MISCELLANEOUS
05 NUCLEAR FUELS
15 GEOTHERMAL ENERGY
54 ENVIRONMENTAL SCIENCES
FLUID FLOW
T CODES
HEAT FLOW
POROUS MATERIALS
COMPUTER CALCULATIONS
RESERVOIR ROCK
RADIOACTIVE WASTE FACILITIES
REMEDIAL ACTION
GEOTHERMAL GRADIENTS
Yucca Mountain Project
Geothermal Legacy