v2306 User Upgrade Guide

• Deprecation and Removal
  • Boundary Conditions
• Rename
  • Function object: patchPostProcessing and patchParticleHistogram
• Input Dictionaries
  • Expressions
  • Function object: electricPotential
  • Function objects: yPlus, wallShearStress
• Parallel
  • More flexible handling of FOAM_IORANKS
  • Command-line specification of MPI threads
  • More details for parProfiling
• Finite-Area Improvements
• Mesh Generation
  • makeFaMesh
• Mesh Checks / Post-processing
  • checkMesh
  • foamToVTK

Deprecation and Removal

Boundary Conditions

The exprFixed and exprMixed boundary conditions are now marked with run-time deprecation warning. The same functionality (and more) is available with uniformFixedValue and uniformMixed boundary conditions, respectively.

Rename

Function object: patchPostProcessing and patchParticleHistogram

The Lagrangian function objects patchPostProcessing and patchParticleHistogram have been renamed as particlePostProcessing and particleHistogram, respectively, to enhance clarity and understanding.

Input Dictionaries

The fixed formatting and restricted precision for #calc and #eval has been removed to avoid unnecessary rounding errors and loss of precision. The string expansion should be more consistent when expressions are evaluated.

Expressions

• patch expressions can now use normal() to obtain the unit-normal instead of writing face()/area().

Function object: electricPotential

The calculation and output of the electric field (E) can be enabled or disabled by using the optional keyword electricField, replacing the previous keyword writeDerivedFields. Also, the name of the electric field (E) can now be specified using the new keyword E.

Function objects: yPlus, wallShearStress

Both yPlus and wallShearStress now have an optional writeFields flag that allows output of the volume fields to be disabled. This can be useful to save disk space and improve speed when only the logged information is of interest.

Parallel

More flexible handling of FOAM_IORANKS

• accept plain lists (space or comma separated) as well as the traditional OpenFOAM lists. This simplifies argument handling with job scripts. For example,

  simpleFoam -ioRanks 0,4,8 ...

  versus

  simpleFoam -ioRanks '(0 4 8)'  ...

  It is also possible to select the IO ranks on a per-host basis:

  simpleFoam -ioRanks host  ...

Command-line specification of MPI threads

• Having MPI_THREAD_MULTIPLE is usually undesirable for performance reasons, but in some cases may be necessary if a linked library expects it. The -mpi-threads command-line option can be used to explicitly request it.

More details for parProfiling

The parProfiling now has more separation between different MPI operations for more granularity in the information:

• broadcast times are separated from reduce/gather/scatter time
• general wait times vs all-to-all wait times
• supports invocation counts, with the requests time/count separated from others (to avoid masking other counts)

Finite-Area Improvements

The minimum edge-length checks have been more consistent and robuster in the presence of small edges. Improved handling of 2D tensor inversion makes for robuster least-square schemes in Finite Area.

Mesh Generation

makeFaMesh

Additional heuristics have been added to handle multiply-connected finite-area edges, which can arise at the centre of a "star" connection or because the patch faces are actually baffles.

In serial case these internal edges are rather dubious in terms of modelling, but when split across processor domains they cause considerable trouble. Although there is not necessarily sufficient information to uniquely determine connectivity, some remedial actions to join edges is often possible. The extra "dangling" edges are relegated to an ignore patch so that they can be handled separately.

While these heuristics solve several problems encountered, more work is still necessary.

Mesh Checks / Post-processing

checkMesh

• added a global topology check in checkMesh and makeFaMesh to detect when boundary patches are multiply connected across edges.

• New -write-edges option for checkMesh: the topologically questionable edges can be written to disk. This new functionality can be a useful diagnostic aid (especially for finiteArea meshes, which remain fragile in the presence of illegal edges).

foamToVTK

When foamToVTK is run with the -no-internal and the -no-boundary options, all loading and reporting of fields is suppressed, which improves its speed significantly.

For regular conversion with fields, the loaded volume fields are temporarily cached for reuse with point interpolation. This reduces the input IO and improves the execution time.

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