This formulation provides C-grid like pressure-flux staggering on an
unstructured mesh which is hugely beneficial for Euler-Euler multiphase
equations as it allows for all forces to be treated in a consistent
manner on the cell-faces which provides better balance, stability and
accuracy.  However, to achieve face-force consistency the momentum
transport terms must be interpolated to the faces reducing accuracy of
this part of the system but this is offset by the increase in accuracy
of the force-balance.

Currently it is not clear if this face-based momentum equation
formulation is preferable for all Euler-Euler simulations so I have
included it on a switch to allow evaluation and comparison with the
previous cell-based formulation.  To try the new algorithm simply switch
it on, e.g.:

PIMPLE
{
    nOuterCorrectors 3;
    nCorrectors      1;
    nNonOrthogonalCorrectors 0;
    faceMomentum     yes;
}

It is proving particularly good for bubbly flows, eliminating the
staggering patterns often seen in the air velocity field with the
previous algorithm, removing other spurious numerical artifacts in the
velocity fields and improving stability and allowing larger time-steps
For particle-gas flows the advantage is noticeable but not nearly as
pronounced as in the bubbly flow cases.

Please test the new algorithm on your cases and provide feedback.

Henry G. Weller
CFD Direct

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1667

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1673

Now interaction methods must be specified for all non-coupled patches.
If this approach proves irritating a warning rather than an error could
be generated.
Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1670

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1669

Thanks to alexeym for patch
Resolves feature-request http://www.openfoam.org/mantisbt/view.php?id=1655

Previous behavior which may be useful for moving-mesh cases can be
selected using the optional entry:
    writeVolume  yes;

The initial volume is written in the log and data file header e.g.:

 #   Source : all
 #   Cells  : 3829
 #   Volume : 9.943164e-01

Also added
    sumMag        | sum of component magnitudes

Previous behavior which may be useful for moving-mesh cases can be
selected using the optional entry:
    writeTotalArea  yes;

The initial total area is written in the log and data file header e.g.:

 #   Source : faceZone f0
 #   Faces  : 8
 #   Area   : 1.063860e-02

Updated tutorials

Description
    Specify an etc file to include when reading dictionaries, expects a
    single string to follow.

    Searches for files from user/group/shipped directories.
    The search scheme allows for version-specific and
    version-independent files using the following hierarchy:
    - \b user settings:
      - ~/.OpenFOAM/\<VERSION\>
      - ~/.OpenFOAM/
    - \b group (site) settings (when $WM_PROJECT_SITE is set):
      - $WM_PROJECT_SITE/\<VERSION\>
      - $WM_PROJECT_SITE
    - \b group (site) settings (when $WM_PROJECT_SITE is not set):
      - $WM_PROJECT_INST_DIR/site/\<VERSION\>
      - $WM_PROJECT_INST_DIR/site/
    - \b other (shipped) settings:
      - $WM_PROJECT_DIR/etc/

    An example of the \c \#includeEtc directive:
    \verbatim
        #includeEtc "etcFile"
    \endverbatim

    The usual expansion of environment variables and other constructs is
    retained.

Use the new -withFunctionObjects command-line option to execute functionObjects

Pe: Create and write volScalarField in addition to the surfaceScalarField for ease of post-processing
Update handling of turbulence models

This allows checkMesh and other mesh manipulation utilities to operate
on the mesh without any time directories being present.

To include 0 use the -zeroTime option

For multi-region cases the default location of blockMeshDict is now system/<region name>

If the blockMeshDict is not found in system then the constant directory
is also checked providing backward-compatibility

Provided by Timo Niemi
Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1650

Resolves bug-report http://openfoam.org/mantisbt/view.php?id=1665

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1659

Resolves bug-report http://openfoam.org/mantisbt/view.php?id=1641

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1650

Note that currently when transportProperties is changed sigma is re-read
from this dictionary but cAlpha is read from fvSolution but cAlpha is
not re-read when fvSolution is changed but transportProperties is not
touched.  To avoid this problem cAlpha would need to be moved to the
transportProperties dictionary which is not ideal or moved out of the
interfaceProperties class back to the top-level solver.

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1657

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1658