Coupled groundwater flow and transport: 2. Thermohaline and 3D convection systems

This work continues the analysis of variable density flow in groundwater systems. It focuses on both thermohaline (double-diffusive) and three-dimensional (3D) buoyancy-driven convection processes. The finite-element method is utilized to tackle these complex non-linear problems in two and three dimensions. The preferred numerical approaches are discussed regarding appropriate basic formulations, balance-consistent discretization techniques for derivative quantities, extension of the Boussinesq approximation, proper constraint conditions, time marching schemes, and computational strategies for solving large systems. Applications are presented for the thermohaline Elder and salt dome problem as well as for the 3D extension of the Elder problem with and without thermohaline effects and a 3D Benard convection process. The simulations are performed by using the package FEFLOW. Conclusions are drawn with respect to numerical efforts and the appropriateness for practical needs. (C) 1998 Elsevier Science Limited. All rights reserved.