Some aquifer tests may be analyzed with flow simulation. Such simulation may be used to analyze ground water contaminant transport problems and aquifer restoration designs. The method is robust and accurate when employed with proper spatial and temporal discretization. Standard finite-element approximations are employed only for terms in the balance equations which describe fluxes of fluid mass, solute mass and energy. These errors are due to fundamental numerical inconsistencies in spatial and temporal approximations for the pressure gradient and density-gravity terms which are involved in velocity calculation.
Spurious velocities can significantly add to the dispersion of solute or energy.
This false dispersion makes accurate simulation of all but systems with very low vertical concentration or temperature gradients impossible, even with fine vertical spatial discretization. Some nonlinear coefficients are evaluated at the new time level of solution by projection, while others are evaluated at the previous time level for non-iterative solutions. All coefficients are evaluated at the new time level for iterative solutions. The finite-element method allows the simulation of irregular regions with irregular internal discretization. This is made possible through use of quadrilateral elements with four corner nodes.