Modelling of non-linear flow using finite element and boundary element methods

Modeling non-linear flow through a rock embankment using finite element (FEM) and boundary integrated element methods (BIEM) are presented and verified using experimental data. Comparison of Forchheimer and exponential expressions for non-linear flow indicates that the Forchheimer expression provides a better fit to experimental data. Both non-linear BIEM and FEM provided good match to experimental data. For two-dimensional linear flow problems in homogeneous media, BIEM is normally more computationally efficient than FEM. For non-linear flow modeling, BIEM loses some of its efficiency since additional integration is required for internal locations but still remains competitive with FEM. To dramatically improve efficiency by eliminating iterative requirements, an average flow direction for a boundary element is selected to "linearize" the non-linear flow equation. Results from the solution of modified governing equation are comparable to solution of the non-linear governing equation using FEM and BIEM.