add InputsDiscretization

docs/source/Inputs_Chapter.rst

@@ -41,6 +41,7 @@ keywords such as ``mfix``, ``amr``, ``geometry``, ``nodal_proj`` etc.
    inputs/InputsProblemDefinition
    inputs/InputsCoupling
    inputs/InputsTimeStepping
+   inputs/InputsDiscretization 
    inputs/InputsInitialization
    inputs/InputsLoadBalancing
    inputs/InputsMultigrid

docs/source/inputs/InputsDiscretization.rst

+.. sec:InputsDiscretization:
+
+Discretization
+==============
+
++---------------------------+-----------------------------------------------------------------------+-------------+--------------+
+| Key                       | Description                                                           |   Type      | Default      |
++===========================+=======================================================================+=============+==============+
+| use_drag_coeff_in_proj_gp | Algebraically consistent p coeff in proj or (default) simplified form |   Bool      |  False       |
++---------------------------+-----------------------------------------------------------------------+-------------+--------------+
+| advection_type            | Predictor-Corrector Method of Lines ("mol") or Godunov ("godunov")    |   String    |  mol         |
++---------------------------+-----------------------------------------------------------------------+-------------+--------------+
+| use_drag_in_godunov       | Include a drag term in the Godunov flux or (default) not              |   Bool      |  False       |
++---------------------------+-----------------------------------------------------------------------+-------------+--------------+
+| redistribution_type       | Use flux ("FluxRedist"), state ("StateRedist") or no ("NoRedist")     |             |              |
+|                           | redistribution                                                        |   String    |  FluxRedist  |
++---------------------------+-----------------------------------------------------------------------+-------------+--------------+
+
+Notes: The code was originally developed with MOL and FluxRedist. Preliminary 
+tests show that the new single-step Godunov method is roughly twice as fast as 
+the predictor-corrector MOL at the same time step (e.g., CFL limited to 0.5). 
+Further, the Godunov method allows for roughly twice the time step, CFL should 
+be limited to 0.9 for stability. Finally, it is recommended that the Godunov 
+method be used in conjunction with StateRedist. While not fully vetted, early 
+tests also show increased stability in complex geometries for a StateRedist-
+Godunov scheme compared to the previous FluxRedist-MOL scheme. 
+