The three governing equations are coupled through the interstitial pore velocity, the dependence of the fluid viscosity on temperature and solute concentration, and the dependence of the fluid density on pressure, temperature, and solute concentration. The basic source-sink term represents wells.
All boundary conditions can be functions of time.
The code calculates global flow, heat and solute balances, including fluxes through specified pressure, temperature and mass-fraction boundaries. Finite-difference techniques are used for spatial and temporal discretization of the governing equations. The modified equations are more tightly coupled and have better stability for the numerical solutions. Two techniques are available for solution of the finite-difference matrix equations. One technique is a direct-elimination solver, using equations reordered by alternating diagonal planes.