Lumped parameter modeling for variable density flow regime

The modeling of density-dependent flow and transport problems in a phreatic aquifer is developed using lumped parameter concepts. The aquifer is discretized into a network of compartments for which the state variables are evaluated at the center of each compartment and its associated physical parameters do not vary within its space. The balance equations are written in terms of a temporal system of Ordinary Differential equations developed on the basis of a previous 2-D horizontal plane continuum model. The numerical scheme is constructed to be conservative and monotone. The corresponding computer code is verified against this previous continuum approach. The numerical results demonstrate very good agreement between the two approaches.