The defaultPatch type currently defaults to empty which is appropriate for 1D
and 2D cases but not when creating the initial blockMesh for snappyHexMesh as
the presence of empty patches triggers the inappropriate application of 2D point
constraint corrections following snapping and morphing. To avoid this hidden
problem a warning is now generated from blockMesh when the defaultPatch is not
explicitly set for cases which generate a default patch, i.e. for which the
boundary is not entirely defined. e.g.
.
.
.
Creating block mesh topology
--> FOAM FATAL IO ERROR:
The 'defaultPatch' type must be specified for the 'defaultFaces' patch, e.g. for snappyHexMesh
defaultPatch
{
name default; // optional
type patch;
}
or for 2D meshes
defaultPatch
{
name frontAndBack; // optional
type empty;
}
.
.
.
All the tutorials have been update to include the defaultPatch specification as
appropriate.
for consistency with the regionToCell topo set source and splitMeshRegions and
provides more logical extension to the multiple and outside point variants insidePoints,
outsidePoint and outsidePoints.
The FOAM file format has not changed from version 2.0 in many years and so there
is no longer a need for the 'version' entry in the FoamFile header to be
required and to reduce unnecessary clutter it is now optional, defaulting to the
current file format 2.0.
The inside or outside region refinement level is now specified using the simple
"level <level>" entry in refinementRegions e.g.
refinementRegions
{
refinementBox
{
mode inside;
level 5;
}
}
rather than
refinementRegions
{
refinementBox
{
mode inside;
levels ((1E15 5));
}
}
where the spurious "1E15" number is not used and the '((...))' is unnecessary clutter.
Originally the only supported geometry specification were triangulated surfaces,
hence the name of the directory: constant/triSurface, however now that other
surface specifications are supported and provided it is much more logical that
the directory is named accordingly: constant/geometry. All tutorial and
template cases have been updated.
Note that backward compatibility is provided such that if the constant/geometry
directory does not exist but constant/triSurface does then the geometry files
are read from there.
The closeness option in surfaceFeatures set in surfaceFeaturesDict, e.g.
closeness
{
// Output the closeness of surface points to other surface elements.
pointCloseness yes;
}
calculates and writes both the internal and external surface "closeness"
measures either of which could be used to set the span refinement in
snappyHexMesh depending on which side of the surface is being meshed which is
specified with either refinement mode "insideSpan" or "externalSpan", e.g. in
the tutorials/mesh/snappyHexMesh/pipe case the inside of the pipe is meshed and
refined based on the internal span using the following specification:
refinementRegions
{
pipeWall
{
mode insideSpan;
levels ((1000 2));
cellsAcrossSpan 40;
}
}
To handle the additional optional specification for the closeness calculation
these settings are now is a sub-dictionary of surfaceFeaturesDict, e.g.
closeness
{
// Output the closeness of surface elements to other surface elements.
faceCloseness no;
// Output the closeness of surface points to other surface elements.
pointCloseness yes;
// Optional maximum angle between opposite points considered close
internalAngleTolerance 80;
externalAngleTolerance 80;
}
In the new tutorial mesh/snappyHexMesh/pipe the pipe diameter changes by a factor
of 2 but the number of cells across the pipe is specified to be constant along
the length using the new "span" refinement mode in which the number of cells
across the span is set to be at least 40:
refinementRegions
{
pipe
{
mode span;
levels ((1000 2)); // Maximum distance and maximum level
cellsAcrossSpan 40;
}
}
This operates in conjunction with the "pointCloseness" option in surfaceFeatures
which writes a surfacePointScalarField of the local span of the domain. Note
that the behaviour of this option is critically dependent on the quality of this
field and the surface may need to be re-triangulated more isotropically to
ensure the "pointCloseness" is accurate and representative of the domain and the
required mesh distribution.
