Publications Details
A boundary integral equation method for steady two-dimensional flow in partially saturated media; Yucca Mountain Site Characterization Project
The governing equation for steady flow in a partially saturated, porous medium can be written in a linear form if one adopts a hydraulic conductivity function that is exponential in the capillary-pressure head. The resulting linear field equation is well suited to numerical solution by the boundary integral equation method (BIEM). The exponential conductivity function is compared to a more complex form often assumed for tuffs, and is found to be a reasonable approximation over limited ranges of pressure head. A computer code based on the BIEM is described and tested. The BIEM is found to exhibit quadratic convergence with element size reduction on smooth solutions and on singular problems, if mesh grading is used. Agreement between results from the BIEM code an a finite-element code that solves the fully nonlinear problem is excellent, and is achieved at a substantial advantage in computer processing time. 26 refs., 23 figs., 8 tabs.