twoPhaseEulerFoam: Update only the fixed-value phi patch fields before constructing the pressure eqn
Avoids small continuity error in parallel

and simplify output format for graphing

With "location yes;"

log:
    fieldMinMax fieldMinMax output:
        min/max(mag(U.air)) = 0 28.309442
        min/max(mag(U.water)) = 0 27.221734

file:
    # Field minima and maxima
    # Time          min(U.air)      max(U.air)      min(U.water)    max(U.water)
    4.00061050e-01  0.00000000e+00  2.87015987e+01  0.00000000e+00  2.71025731e+01
    4.00134265e-01  0.00000000e+00  2.86505310e+01  0.00000000e+00  2.71134246e+01
    4.00222098e-01  0.00000000e+00  2.85937449e+01  0.00000000e+00  2.71255302e+01

With "location no;"

log:
    fieldMinMax fieldMinMax output:
        min(mag(U.air)) = 0 at location (-0.058373423 -0.15376628 0.021017389)
        max(mag(U.air)) = 28.701599 at location (-0.24002836 0.0053456235 3.8964638)
        min(mag(U.water)) = 0 at location (-0.058373423 -0.15376628 0.021017389)
        max(mag(U.water)) = 27.102573 at location (-0.24002836 0.0053456235 3.8964638)

file:
    # Field minima and maxima
    # Time          field           min             location(min)   max             location(max)
    4.00061050e-01  U.air           0.00000000e+00  (-5.83734226e-02 -1.53766281e-01 2.10173892e-02)        2.87015987e+01  (-2.40028359e-01 5.34562354e-03 3.89646377e+00)
    4.00061050e-01  U.water         0.00000000e+00  (-5.83734226e-02 -1.53766281e-01 2.10173892e-02)        2.71025731e+01  (-2.40028359e-01 5.34562354e-03 3.89646377e+00)

New layout:

    # Probe 0 (0.0254 0.0253 0)
    # Probe 1 (0.0508 0.0253 0)
    # Probe 2 (0.0762 0.0253 0)
    #       Probe             0             1             2
    #        Time
            1e-05        142974        128861        115934
            2e-05      -69444.1        -62541      -56395.7
            3e-05      -1546.81      -1445.94      -1154.79

to create single layer extrusions with wedge and empty front and back
patches respectively.

refineMesh: Improved command-line argument handling to be more consistent with other OpenFOAM utilities

    Command-line option handling:
    + If -all specified or no refineMeshDict exists or, refine all cells
    + If -dict <file> specified refine according to <file>
    + If refineMeshDict exists refine according to refineMeshDict

    When the refinement or all cells is selected apply 3D refinement for 3D
    cases and 2D refinement for 2D cases.

    cacheAgglomeration true;
    agglomerator    faceAreaPair;
    nCellsInCoarsestLevel 10;
    mergeLevels     1;

Generate fatal error if iso-surface field cannot be found

This allows PIMPLE solvers to operate in SIMPLE mode

twoPhaseEulerFoam: In the limit of phase-fraction->0 the velocity is calculated from a force balance

Rather than forcing the dispersed-phase velocity -> the continuous-phase
velocity as the phase-fraction -> 0 the velocity is now calculated from
a balance of pressure, buoyancy and drag forces.  The advantage is now
liquid or particles are not carried out of bubble-column of
fluidised-beds by the fictitious drag caused by forcing the
phase-velocities becoming equal in the limit.

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1680

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1679

consistent with multiphaseInterFoam and other VoF solvers

nLimiterIter: Number of iterations during limiter construction
    3 (default) is sufficient for 3D simulations with a Courant number 0.5 or so
    For larger Courant numbers larger values may be needed but this is
    only relevant for IMULES and CMULES

smoothLimiter: Coefficient to smooth the limiter to avoid "diamond"
    staggering patters seen in regions of low particle phase-fraction in
    fluidised-bed simulations.

    The default is 0 as it is not needed for all simulations.
    A value of 0.1 is appropriate for fluidised-bed simulations.
    The useful range is 0 -> 0.5.
    Values larger than 0.5 may cause excessive smearing of the solution.

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1675

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