Channeling characteristics of flow and solute transport through a rough-surfaced fracture
Calculations for the flow and solute transport through a single rough-surfaced fracture are carried out. The fracture plane is discretized into square meshes to which variable apertures are assigned. The spatially varying apertures in the single fractures are generated using geostatistical methods, based on a given aperture density distribution and a specified spatial correlation length. Constant head boundary conditions are assumed for the flow in the single fracture. The fluid potential at each mesh intersection is computed and the steady state flowrates between all adjacent meshes are obtained. The calculations for flow in two-dimensions show that fluid flows unevenly in a single fracture, and that it takes place in a few preferred paths. The solute transport is calculated using a particle tracking method. The channeling characteristics of fluid flow and solute transport phenomena as a function of the fracture geometry (aperture density distribution and spatial correlation length) is demonstrated; and the implication to experimental measurements are discussed. The two-dimensional solute transport results are then interpretated in terms of a one-dimensional channel model: a system of independent variable-aperture channels acting as flow paths for the solute transport. The result that the two-dimensional breakthrough curves are reproducible by the one-dimensional conceptual model sheds much light on the potential utility of the simple one-dimensional channel model to interpret flow and solute transport in both two- and three-dimensional fractured systems. This approach entails an enormous saving of computation effort.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA); Royal Inst. of Tech., Stockholm (Sweden). Dept. of Chemical Engineering
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6164993
- Report Number(s):
- LBL-23195; ON: DE87013970
- Country of Publication:
- United States
- Language:
- English
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