MT3D offers some alternative solution formulations. MT3DMS Manual and Supplement

Finite Difference is computationally efficient (no packet tracking) and small mass balance errors, but there is significant numerical dispersion and overshoot/undershoot

MOC reduces numerical dispersion, but is not computationally efficient (particularly for 3D) and has problems with mass balance review of the discussion of the MOC method from unit 13

The alternative MOC solutions offer the ADVANTAGE/DISADVANTAGE of :

Modified MOC which improves efficiency because it uses only one packet at the center of each cell and tracks it backwards to capture the advective term, but introduces numerical dispersion on sharp front problems.

Hybrid MOC which forward tracks dynamically distributed packets near the sharp concentration front and backward tracks in areas far from the front, when the front dissipates forward tracking packets are removed and MMOC is used. This is the best option for MOC application, but it can be difficult to select appropriate parameters for switching from HMOC to MMOC.

TVD (third order total-variation-diminishing scheme) is a higher order finite-difference (finite-volume) methond and is computationally efficient, conserves mass, and reduces numerical dispersion and overshoot/undershoot, although does not eliminate it.

*Consider initial conditions in MT3D

*Consider boundary conditions in MT3D

*Consider discretization in MT3D

*Consider velocity interpolation in MT3D

Consider packet tracking in MT3D

Consider dynamic packet distribution in MT3D

*Consider sources/sinks in MT3D

*Consider adsorption in MT3D

*Consider decay in MT3D

*Consider dispersion coefficients in MT3D

*Consider mass balance in MT3D

*Consider time step criteria in MT3D

Consider dual medium

MT3D modules

*Consider MT3D modules

MT3D output

*Consider MT3D output

GO "BACK" and generate an MT3D simulation for your class project.