A new boundary element formulation for time‐dependent confined and unconfined aquifer problems

Abstract

The boundary element method (BEM) is used extensively for the solution of unsteady groundwater flow problems in confined or unconfined aquifers. In recent literature most of these studies concentrate on the efficient solution of resultant matrix equations in time, since the advantages and efficiency of BEM over other domain methods is well‐established for spatial approximation aspects of the technique. Here a new numerical time integration procedure is presented for boundary element solution of time‐dependent aquifer problems. The proposed algorithm reduces the resulting finite difference time integration process to a boundary only computation, if desired, and extends the efficiency of the BEM to time‐dependent problems which is an important step forward for boundary formulation approach. The proposed method is tested with considerable success on two classical aquifer problems. Results obtained are presented comparatively with analytical, finite element, dual reciprocity, and standard boundary element time integration procedures, clearly demonstrating the efficiency and accuracy of the proposed method.