Community contribution from Johan Roenby, DHI

IsoAdvector is a geometric Volume-of-Fluid method for advection of a
sharp interface between two incompressible fluids. It works on both
structured and unstructured meshes with no requirements on cell shapes.
IsoAdvector is as an alternative choice for the interface compression
treatment with the MULES limiter implemented in the interFoam family
of solvers.

The isoAdvector concept and code was developed at DHI and was funded
by a Sapere Aude postdoc grant to Johan Roenby from The Danish Council
for Independent Research | Technology and Production Sciences (Grant-ID:
DFF - 1337-00118B - FTP).
Co-funding is also provided by the GTS grant to DHI from the Danish
Agency for Science, Technology and Innovation.

The ideas behind and performance of the isoAdvector scheme is
documented in:

    Roenby J, Bredmose H, Jasak H. 2016 A computational method for sharp
    interface  advection. R. Soc. open sci. 3: 160405.
    [http://dx.doi.org/10.1098/rsos.160405](http://dx.doi.org/10.1098/rsos.160405)

Videos showing isoAdvector's performance with a number of standard
test cases can be found in this youtube channel:

    https://www.youtube.com/channel/UCt6Idpv4C8TTgz1iUX0prAA

Project contributors:

* Johan Roenby <jro@dhigroup.com> (Inventor and main developer)
* Hrvoje Jasak <hrvoje.jasak@fsb.hr> (Consistent treatment of
  boundary faces including processor boundaries, parallelisation,
  code clean up
* Henrik Bredmose <hbre@dtu.dk> (Assisted in the conceptual
  development)
* Vuko Vukcevic <vuko.vukcevic@fsb.hr> (Code review, profiling,
  porting to foam-extend, bug fixing, testing)
* Tomislav Maric <tomislav@sourceflux.de> (Source file
  rearrangement)
* Andy Heather <a.heather@opencfd.co.uk> (Integration into OpenFOAM
  for v1706 release)

See the integration repository below to see the full set of changes
implemented for release into OpenFOAM v1706

    https://develop.openfoam.com/Community/Integration-isoAdvector

Adding special alphaCourantNo for overlaping
Adding bounded term to UEq.H for overInterDyMFoam
Changing to NO_WRITE for the cellMask field
Changing twoSimpleRotors tutorial to open domain

Fixing humidityTemperatureCoupled problem in parallel
Adding Allrun-parallel to externalSolarLoad and windshieldCondensation tutorials

- Requires (1L << N) instead of (1 << N), otherwise it overflows
  and the result is zero.

Adds overset discretisation to selected physics:
- diffusion : overLaplacianDyMFoam
- incompressible steady : overSimpleFoam
- incompressible transient : overPimpleDyMFoam
- compressible transient: overRhoPimpleDyMFoam
- two-phase VOF: overInterDyMFoam

The overset method chosen is a parallel, fully implicit implementation
whereby the interpolation (from donor to acceptor) is inserted as an
adapted discretisation on the donor cells, such that the resulting matrix
can be solved using the standard linear solvers.

Above solvers come with a set of tutorials, showing how to create and set-up
simple simulations from scratch.

- as per foamToEnsight, foamToEnsightParts.
  Allows the user to specify different output directories.

- elminate the foamVtkFormatter operator() in favour of xmlAttr.
  Improves readability and the purpose is clearer.

- Use on/off vs longer compressed/uncompressed.
  For consistency, replaced yes/no with on/off.

- Avoid the combination of binary/compressed,
  which is disallowed and provokes a warning anyhow

Updating fvSolution's for closed domains for chtMultiRegionFoam cases

simpleRho or limiting p.

Update pEq for close domains.

2)Adapting divU in TEqn.H for compressibleInterDyMFoam and compressibleInterFoam
3)Re-instated sixDoFRigidBodyDisplacement as patch for pointFields. It allows to use a different fvDynamincMesh type
independently of the BC's

- use proxy writer for triSurface writing

Modification on rhoPimpleFoam pEq's for handling rho thermo and incompressible EoS. Adding rho limiters if p is limited.
This is important when LTS stepping or large Co number is used.

Updating rhoBuoyantPimpleFoam to handle closed domain for rho thermo and incompressible Eos.
Consolidating chtMultiRegionSimpleFoam and chtMultiRegionFoam pEqs to use the same formulation as rhoBuoyantPimpleFoam and
rhoBuoyantSimpleFoam

- with the xml append format it is possible to write raw binary
  (instead of base64), but the writer becomes more complicated.
  Either needs two passes to create, or need to allocate a block
  of space for the header information (like VTK itself does) and
  write later.

    * internalWriter
    * patchWriter
    * surfaceMeshWriter
    * lagrangianWriter

 Also these special purpose ones:
    * foamVtkWriteSurfFields

ENH: noiseModels - updated parallel usage (no longer needs proc dirs) and apply input data validation

- this shifts responsibility away from caller to the individual writers
  for knowing which file formats are supported and which file ending is
  appropriate. When the writer receives the output format request,
  it can elect to downgrade or otherwise adjust it to what it can
  actually manage (eg, legacy vs xml vs xml-append).

  But currently still just with legacy format backends.

- was generally somewhat fragile. The main problem stems from the fact
  that several interfaces may be attached to a boundary. No trivial
  means of solving this without too much work for a feature that is only
  "nice-to-have".

- Programming convenience.
  Eg, cos(45_deg) vs cos(degToRad(45))

STYLE: conversions marked as constexpr and noexcept

- the NamedEnum wrapper is somewhate too rigid.
  * All enumerated values are contiguous, starting as zero.
  * The implicit one-to-one mapping precludes using it for aliases.
  * For example, perhaps we want to support alternative lookup names for an
    enumeration, or manage an enumeration lookup for a sub-range.

- no penalty compared to Tuple2, potential future benefits with C++
  constructor forwarding.

- Remove the unused enums() method since it delivers wholly unreliable
  results. It is not guaranteed to cover the full enumeration range,
  but only the listed names.

- Remove the unused strings() method.
  Duplicated functionality of the words(), but was never used.

- Change access of words() method from static to object.
  Better code isolation. Permits the constructor to take over
  as the single point of failure for bad input.

- Add values() method

- do not expose internal (HashTable) lookup since it makes it more
  difficult to enforce constness and the implementation detail should
  not be exposed. However leave toc() and sortedToc() for the interface.

STYLE: relocated NamedEnum under primitives (was containers)

- internal typedef as 'value_type' for some consistency with STL conventions

- The unset() method never auto-vivifies, whereas the set() method
  always auto-vivifies. In the case where set() is called with a zero
  for its argument - eg, set(index, 0) - this should behave
  identically to an unset() and not auto-vivify out-of-range entries.