and make '-explicitFeatures' the option to use explicitFeatures. When implicitFeatures
is used, a surfaceFeaturesDict file is not written out to the system directory
including blockMeshDict, surfaceFeaturesDict and snappyHexMeshDict, based on the
case surface geometry.
Description
Preconfigures blockMeshDict, surfaceFeaturesDict and snappyHexMeshDict
files based on the case surface geometry files.
Starting from a standard OpenFOAM case, this utility locates surface
geometry files, e.g. OBJ, STL format, in the constant/geometry directory.
It writes out the configuration files for mesh generation with
snappyHexMesh based on assumptions which can be overridden by options on
the command line.
The utility processes the surface geometry files, attempting to anticipate
their intended purpose, trying in particular to recognise whether the
domain represents an external or internal flow. If there is a surface
which is closed, and is either single or surrounds all other surfaces,
then it is assumed that it forms the external boundary of an internal
flow. This assumption is overridden if the bounds of the background mesh
are specified using the '-bounds' option and they are more than 50% larger
than the surface bounds.
Surfaces which form boundaries of the domain may contain named regions
that are intended to become patches in the final mesh. Any surface region
whose name begins with 'inlet' or 'outlet' will become a patch of the same
name in the final mesh. On an external surface (for an internal flow),
regions can be identified as inlets and outlets using the '-inletRegions'
and '-outletRegions' options, respectively. When either option specifies a
single region, the resulting patch name will be specifically 'inlet' or
'outlet', respectively. Surfaces which are contained within the domain,
which do not surround or intersect other surfaces, are assumed by default
to be wall patches. Any closed surface which surrounds another (but not an
external surface) is used to form a cellZone within the mesh. Any surface
can be specifically identified as a cellZone with the '-cellZones' option,
with the additional '-baffles' and '-rotatingZones' options available to
assign a surface to a more specific use.
The background mesh for snappyHexMesh is a single block generated by
blockMesh, configured using a blockMeshDict file. The block bounds are
automatically calculated, but can be overridden by the '-bounds'
option. The number of cells is calculated to produce a fairly small
prototype mesh. The cell density can be overridden by the '-nCells' option
or can be scaled up by an integer factor using the '-refineBackground'
option. When the background mesh is required to form patches in the final
mesh, e.g. for an external flow, the user can specify the names and types
of the patches corresponding to the six block faces using options such as
'-xMinPatch', '-xMaxPatch', etc. The name and type of the default patch,
formed from block faces which are not configured, can also be specified
with the '-defaultPatch' option. The utility provides placeholder entries
for all block faces unless the '-clearBoundary' option is used. A special
'-cylindricalBackground' option generates a cylindrical background mesh,
oriented along the z-axis along x = y = 0.
The snappyHexMesh configuration is generated automatically, applying a set
of defaults to the main configuration parameters. By default, explicit
feature capturing is configured, for which a surfaceFeaturesDict file is
written for the user to generate the features files with the
surfaceFeatures utility. Implicit feature capturing can alternatively be
selected with the '-implicitFeatures' option. Refinement levels can be
controlled with a range of options including: '-refinementLevel' for the
baseline refinement level; '-refinementSurfaces' for levels on specific
surfaces; '-refinementRegions' for levels inside specific surfaces;
'-refinementBoxes' for quick, box-shaped refinement regions specified by
min and max bounds; '-refinementDists' for distance-based refinement; and
'-nCellsBetweenLevels' to control the transition between refinement
levels. A '-layers' option specifies additional layers of cells at wall
boundaries. The insidePoint parameter is set to '(0 0 0)' by default but
can be overridden using the '-insidePoint' option.
