Two Perturbation Boundary Element Codes for Steady Groundwater Flow in Heterogeneous Aquifers

Abstract

Publisher Summary This chapter discusses two perturbation boundary element codes for steady groundwater flow in heterogeneous aquifers. The boundary element method (BEM) has received increased attention as a method capable of solving problems containing material heterogeneity. The search for the efficient codes continues. The new technique expands the potential into a perturbation series and solves the resultant Laplace and Poisson equations, using the existing BEM codes. The method is highly efficient for slow to moderately varying hydraulic conductivities. For problems with hydraulic conductivity varying over several orders of magnitude within the domain, however, this technique failed to provide a converged solution. The chapter presents two BEM codes that seek to circumvent the convergence problems in the original formulation. The first method adheres to the earlier formulation, but now incorporates a zoning concept. This is to permit the use of slow varying functions for the hydraulic conductivity within each zone while, the variability throughout the entire flow field is large. In this approach, the numerical process involves domain integrations.