Application
engineCompRatio
Description
Calculate the compression ratio of the engine combustion chamber
If the combustion chamber is not the entire mesh a \c cellSet or
\c cellZone name of the cells in the combustion chamber can be provided.
Usage
\b engineCompRatio [OPTION]
- \par -cellSet \<name\>
Specify the cellSet name of the combustion chamber
- \par -cellZone zoneName
Specify the cellZone name of the combustion chamber
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.
setFormat no longer defaults to the value of graphFormat optionally set in
controlDict and must be set in the functionObject dictionary.
boundaryFoam, financialFoam and pdfPlot still require a graphFormat entry in
controlDict but this is now read directly rather than by Time.
the -solver option also disables the default loading of all libraries, instead
loading just the specified solver module library and dependencies.
It is generally more useful to load all the libraries when searching for model,
boundary condition etc. rather than having to list specific libraries to search
unless only the contents of the standard libraries loaded into a solver module
are to be searched, in which case the -solver option can be used.
This can be useful when reusing thermo configurations across multiple
setups. In one simulation, the fluid might be entirely air, and in
another there might be additional pollutant or fuel species. This could
be defined without changing the species' thermo enties as follows:
"(mixture|air)"
{
specie
{
molWeight 28.9;
}
thermodynamics
{
Hf 0;
Cv 724.8;
}
transport
{
mu 1.84e-05;
Pr 0.7;
}
}
This was semi-supported before, but it lead to the wrong name (i.e., the
wildcard string) being stored in the base specie class. Now the name is
passed through the thermo constructors, so it is always correct.
e.g. the simple exact match search
foamToC -allLibs -search VoFTurbulenceDamping
generates:
VoFTurbulenceDamping is in table
fvModel libVoFTurbulenceDamping.so
but the regular expression search
foamToC -allLibs -search "VoF.*"
generates the results for all names in all tables containing the sub-string "VoF":
VoFCavitation is in table
fvModel libVoFCavitation.so
VoFSolidificationMeltingSource is in table
fvModel libVoFSolidificationMeltingSource.so
VoFClouds is in table
fvModel libVoFClouds.so
VoFFilmTransfer is in table
fvModel libfilmVoFTransfer.so
VoFTurbulenceDamping is in table
fvModel libVoFTurbulenceDamping.so
This avoids potential hidden run-time errors caused by solvers running with
boundary conditions which are not fully specified. Note that "null-constructor"
here means the constructor from patch and internal field only, no data is
provided.
Constraint and simple BCs such as 'calculated', 'zeroGradient' and others which
do not require user input to fully specify their operation remain on the
null-constructor table for the construction of fields with for example all
'calculated' or all 'zeroGradient' BCs.
A special version of the 'inletOutlet' fvPatchField named 'zeroInletOutlet' has
been added in which the inlet value is hard-coded to zero which allows this BC
to be included on the null-constructor table. This is useful for the 'age'
functionObject to avoid the need to provide the 'age' volScalarField at time 0
unless special inlet or outlet BCs are required. Also for isothermalFilm in
which the 'alpha' field is created automatically from the 'delta' field if it is
not present and can inherit 'zeroInletOutlet' from 'delta' if appropriate. If a
specific 'inletValue' is require or other more complex BCs then the 'alpha'
field file must be provided to specify these BCs as before.
Following this improvement it will now be possible to remove the
null-constructors from all fvPatchFields not added to the null-constructor
table, which is most of them, thus reducing the amount of code and maintenance
overhead and making easier and more obvious to write new fvPatchField types.
gcc-13 has new code checking and warning mechanisms which are useful but not
entirely robust and produce many false positives, particularly with respect to
local references:
warning: possibly dangling reference to a temporary
This commit resolves many of the new warning messages but the above false
warnings remain. It is possible to switch off this warning but as it also
provides some useful checks it is currently left on.
This new class hierarchy replaces the distributions previously provided
by the Lagrangian library.
All distributions (except fixedValue) now require a "size exponent", Q,
to be specified along with their other coefficients. If a distribution's
CDF(x) (cumulative distribution function) represents what proportion of
the distribution takes a value below x, then Q determines what is meant
by "proportion":
- If Q=0, then "proportion" means the number of sampled values expected
to be below x divided by the total number of sampled values.
- If Q=3, then "proportion" means the expected sum of sampled values
cubed for values below x divided by the total sum of values cubed. If
x is a length, then this can be interpreted as a proportion of the
total volume of sampled objects.
- If Q=2, and x is a length, then the distribution might represent the
proportion of surface area, and so on...
In addition to the user-specification of Q defining what size the given
distribution relates to, an implementation that uses a distribution can
also programmatically define a samplingQ to determine what sort of
sample is being constructed; whether the samples should have an equal
number (sampleQ=0), volume (sampleQ=3), area (sampleQ=2), etc...
A number of fixes to the distributions have been made, including fixing
some fundamental bugs in the returned distribution of samples, incorrect
calculation of the distribution means, renaming misleadingly named
parameters, and correcting some inconsistencies in the way in which
tabulated PDF and CDF data was processed. Distributions no longer
require their parameters to be defined in a sub-dictionary, but a
sub-dictionary is still supported for backwards compatibility.
The distributions can now generate their PDF-s as well as samples, and a
test application has been added (replacing two previous applications),
which thoroughly checks consistency between the PDF and the samples for
a variety of combinations of values of Q and sampleQ.
Backwards incompatible changes are as follows:
- The standard deviation keyword for the normal (and multi-normal)
distribution is now called 'sigma'. Previously this was 'variance',
which was misleading, as the value is a standard deviation.
- The 'massRosinRammler' distribution has been removed. This
functionality is now provided by the standard 'RosinRammler'
distributon with a Q equal to 0, and a sampleQ of 3.
- The 'general' distribution has been split into separate distributions
based on whether PDF or CDF data is provided. These distributions are
called 'tabulatedDensity' and 'tabulatedCumulative', respectively.
This completes commit 381e0921 and permits patches on the "top" of
extruded regions to determine the point locations opposite as well as
the face centres and areas. This means that patches with dissimilar
meshes can now be coupled via the patchToPatch interpolation engine.
A few fixes have also been applied to extrudeToRegionMesh to make the
intrude option compatibile with extrusion into internal faces and
between opposing zones/sets/patches. The 'shadow' entries used for
extrusion inbetween opposing zones/sets/patches have also been renamed
to 'opposite' for consistency with the patch names and patch types
entries; e.g.,
faceZones (fz1 fz3);
oppositeFaceZones (fz2 fz4); // <-- was 'faceZonesShadow'
faceSets (fs1 fs3);
oppositeFaceSets (fs2 fs4); // <-- was 'faceSetsShadow'
patches (p1 p3);
oppositePatches (p2 p4); // <-- was 'patchesShadow'
Now the -allLibs option loads all the libraries without listing them to reduce
the amount of output when it is not needed and the new -listAllLibs option loads
all the libraries and lists them as they are loaded which may be useful to find
libraries which do not load due to duplicate entries for example.
With the new film implementation the single cell layer film region is extruded
into (overlapping with) the primary/fluid region which can now be generated with
extrudeToRegionMesh using the new 'intrude' option, e.g. for the
tutorials/modules/multiRegion/film/splashPanel case the extrudeToRegionMeshDict
contains:
region film;
patches (film);
extrudeModel linearNormal;
intrude yes;
adaptMesh no;
patchTypes (mappedExtrudedWall);
patchNames (film);
regionPatchTypes (filmWall);
regionPatchNames (wall);
regionOppositePatchTypes (mappedFilmSurface);
regionOppositePatchNames (surface);
nLayers 1;
expansionRatio 1;
linearNormalCoeffs
{
thickness 0.002;
}
genericPatches is linked into mesh generation and manipulation utilities but not
solvers so that the solvers now check for the availability of the specified
patch types. Bugs in the tutorials exposed by this check have been corrected.
e.g. in extrudeToRegionMeshDict:
// Generate the region named film
region film;
// from the patch extrudeWall
patches (extrudeWall);
// generating mapped patches for the extruded region
adaptMesh yes;
// New options:
// Set the type of the mapped patch on the existing mesh to mappedWall ...
patchTypes (mappedWall);
// ... and name to wall
patchNames (wall);
// Set the type of the mapped patch on the region mesh to mappedFilmWall ...
regionPatchTypes (mappedFilmWall);
// ... and name to wall
regionPatchNames (wall);
// Set the type of the opposite patch on the region mesh to empty ...
regionOppositePatchTypes (empty);
// ... and name to empty
regionOppositePatchNames (empty);
All the above entries are optional and if not present the previous behaviour is
reproduced.
The new option takes a value indicating which cell types should be
written out as polyhedra. The values are as follows:
none: No polyhedral cells are written. Cells which match specific
shapes (hex, pyramid, prism, ...) are written as their
corresponding VTK cell types. Arbitrary polyhedral cells
that do not match a specific shape are decomposed into
tetrahedra.
polyhedra: Only arbitrary polyhedral cells are written as a VTK
polyhedron. Cells that match specific shapes are written as
their corresponding VTK cell types.
all: All cells are written as a VTK polyhedron.
The default is 'none', which retains the previous default behaviour.
Cell-to-cell interpolation has been moved to a hierarchy separate from
meshToMesh, called cellsToCells. The meshToMesh class is now a
combination of a cellsToCells object and multiple patchToPatch objects.
This means that when only cell-to-cell interpolation is needed a basic
cellsToCells object can be selected.
Cell-to-cell and vol-field-to-vol-field interpolation now has two well
defined sets of functions, with a clear distinction in how weights that
do not sum to unity are handled. Non-unity weights are either
normalised, or a left-over field is provided with which to complete the
weighted sum.
The left-over approach is now consistently applied in mapFieldsPar,
across both the internal and patch fields, if mapping onto an existing
field in the target case. Warning are now generated for invalid
combinations of settings, such as mapping between inconsistent meshes
without a pre-existing target field.
All mapping functions now take fields as const references and return tmp
fields. This avoids the pattern in which non-const fields are provided
which relate to the source, and at some point in the function transfer
to the target. This pattern is difficult to reason about and does not
provide any actual computational advantage, as the fields invariably get
re-allocated as part of the process anyway.
MeshToMesh no longer stores the cutting patches. The set of cutting
patches is not needed anywhere except at the point of mapping a field,
so it is now supplied to the mapping functions as an argument.
The meshToMesh topology changer no longer supports cutting patch
information. This did not previously work. Cutting patches either get
generated as calculated, or they require a pre-existing field to specify
their boundary condition. Neither of these options is suitable for a
run-time mesh change.
More code has been shared with patchToPatch, reducing duplication.
