The radiation modelling library has been moved out of
thermophysicalProperties into the top-level source directory. Radiation
is a process, not a property, and belongs alongside turbulence,
combustion, etc...
The namespaces used within the radiation library have been made
consistent with the rest of the code. Selectable sub-models are in
namespaces named after their base classes. Some models have been
renamed remove the base type from the suffix, as this is unnecessary.
These renames are:
Old name: New name:
binaryAbsorptionEmission binary
cloudAbsorptionEmission cloud
constantAbsorptionEmission constant
greyMeanAbsorptionEmission greyMean/greyMeanCombustion
greyMeanSolidAbsorptionEmission greyMeanSolid
wideBandAbsorptionEmission wideBand/wideBandCombustion
cloudScatter cloud
constantScatter constant
mixtureFractionSoot mixtureFraction
Some absorption-emission models have been split into versions which do
and don't use the heat release rate. The version that does has been
given the post-fix "Combustion" and has been moved into the
combustionModels library. This removes the dependence on a registered
Qdot field, and makes the models compatible with the recent removal of
that field from the combustion solvers.
This tutorial serves as a reference of how to create a multi-region
mesh with layer addition.
The multiRegionHeater tutorial and it's variants have been removed as
the geometry is not meaningful and the functionality is now all
represented elsewhere.
This allows coefficients of the constantAbsorptionEmission and
constantScatter to be entered as pure numbers, with the name and
dimensions set automatically, rather than having to specify them
manually.
This function object writes out the heat release rate field for a
combustion model. This is useful for solvers where combustion is
optional, and which do not therefore write out the heat release rate by
default; e.g., chtMultiRegionFoam and reactingTwoPhaseEulerFoam.
The tutorial has been converted from two-dimensions to a wedge and the
flow has been swirl stabilised. The turbulence parameters have been made
physical. The transport schemes have been increased to second order. The
reaction mechanism has been changed to one from a publically accessible
reference. The gas thermodynamics have been made incompressible, and the
pressure offset around zero, which improves the behaviour of the
pressure solution.
Added headers to all reactions files to prevent warnings in paraview.
Added references for known mechanisms. Removed unused reaction and
thermophysical property files.
Now for transient simulations "Final" solver settings are required for ALL
equations providing consistency between the solution of velocity, energy,
composition and radiation properties.
However "Final" relaxation factors are no longer required for fields or
equations and if not present the standard value for the variable will be
applied. Given that relaxation factors other than 1 are rarely required for
transient runs and hence the same for all iterations including the final one
this approach provide simpler input while still providing the flexibility to
specify a different value for the final iteration if required. For steady cases
it is usual to execute just 1 outer iteration per time-step for which the
standard relaxation factors are appropriate, and if more than one iteration is
executed it is common to use the same factors for both. In the unlikely event
of requiring different relaxation factors for the final iteration this is still
possible to specify via the now optional "Final" specification.
to avoid the need to evaluate departure functions and simplify evaluation of the
temperature. In general it makes more sense to use and e/Cv based
thermodynamics when solving for internal energy rather than h/Cp and have
convert between the energy forms.
All related tutorials and test cases have also been updated.
Changed liquid thermo from sensibleEnthalpy to sensibleInternalEnergy in
tutorials. It is generally more convergent and stable to solve for internal
energy if the fluid is incompressible or weakly compressible.
To switch-off radiation set
radiationModel none;
in radiationProperties which instantiates "null" model that does not read any
data or coefficients or evaluate any fields.
The sampled sets have been renamed in a more explicit and consistent
manner, and two new ones have also been added. The available sets are as
follows:
arcUniform: Uniform samples along an arc. Replaces "circle", and
adds the ability to sample along only a part of the circle's
circumference. Example:
{
type arcUniform;
centre (0.95 0 0.25);
normal (1 0 0);
radial (0 0 0.25);
startAngle -1.57079633;
endAngle 0.52359878;
nPoints 200;
axis x;
}
boundaryPoints: Specified point samples associated with a subset of
the boundary. Replaces "patchCloud". Example:
{
type boundaryPoints;
patches (inlet1 inlet2);
points ((0 -0.05 0.05) (0 -0.05 0.1) (0 -0.05 0.15));
maxDistance 0.01;
axis x;
}
boundaryRandom: Random samples within a subset of the boundary.
Replaces "patchSeed", but changes the behaviour to be entirely
random. It does not seed the boundary face centres first. Example:
{
type boundaryRandom;
patches (inlet1 inlet2);
nPoints 1000;
axis x;
}
boxUniform: Uniform grid of samples within a axis-aligned box.
Replaces "array". Example:
{
type boxUniform;
box (0.95 0 0.25) (1.2 0.25 0.5);
nPoints (2 4 6);
axis x;
}
circleRandom: Random samples within a circle. New. Example:
{
type circleRandom;
centre (0.95 0 0.25);
normal (1 0 0);
radius 0.25;
nPoints 200;
axis x;
}
lineFace: Face-intersections along a line. Replaces "face". Example:
{
type lineFace;
start (0.6 0.6 0.5);
end (0.6 -0.3 -0.1);
axis x;
}
lineCell: Cell-samples along a line at the mid-points in-between
face-intersections. Replaces "midPoint". Example:
{
type lineCell;
start (0.5 0.6 0.5);
end (0.5 -0.3 -0.1);
axis x;
}
lineCellFace: Combination of "lineFace" and "lineCell". Replaces
"midPointAndFace". Example:
{
type lineCellFace;
start (0.55 0.6 0.5);
end (0.55 -0.3 -0.1);
axis x;
}
lineUniform: Uniform samples along a line. Replaces "uniform".
Example:
{
type lineUniform;
start (0.65 0.3 0.3);
end (0.65 -0.3 -0.1);
nPoints 200;
axis x;
}
points: Specified points. Replaces "cloud" when the ordered flag is
false, and "polyLine" when the ordered flag is true. Example:
{
type points;
points ((0 -0.05 0.05) (0 -0.05 0.1) (0 -0.05 0.15));
ordered yes;
axis x;
}
sphereRandom: Random samples within a sphere. New. Example:
{
type sphereRandom;
centre (0.95 0 0.25);
radius 0.25;
nPoints 200;
axis x;
}
triSurfaceMesh: Samples from all the points of a triSurfaceMesh.
Replaces "triSurfaceMeshPointSet". Example:
{
type triSurfaceMesh;
surface "surface.stl";
axis x;
}
The headers have also had documentation added. Example usage and a
description of the control parameters now exists for all sets.
In addition, a number of the algorithms which generate the sets have
been refactored or rewritten. This was done either to take advantage of
the recent changes to random number generation, or to remove ad-hoc
fixes that were made unnecessary by the barycentric tracking algorithm.
runApplication isn't needed for foamDictionary as it doesn't log
anything of consequence. Using runApplication leads to false unconfirmed
completion warnings in the test loop as foamDictionary does not generate
an end statement.
The changeDictonary setup has been removed and replaced with a more
typical boundary condition setup. Dictionary variables and wildcards
have been used to reduce repetition of the simulation parameters.
The tutorial now also demonstrates how to run a multi-region CHT case
completely in parallel. If run-time post processing was being utilised
there would be no need for reconstruction at any point.
Now if a <field> file does not exist first the compressed <field>.gz file is
searched for and if that also does not exist the <field>.orig file is searched
for.
This simplifies case setup and run scripts as now setField for example can read
the <field>.orig file directly and generate the <field> file from it which is
then read by the solver. Additionally the cleanCase function used by
foamCleanCase and the Allclean scripts automatically removed <field> files if
there is a corresponding <field>.orig file. So now there is no need for the
Allrun scripts to copy <field>.orig files into <field> or for the Allclean
scripts to explicitly remove them.
This is a CHT case which uses snappyHexMesh. It is a tutorial, in the
traditional sense, in that it has been designed for training purposes.
It does not rely on changeDictionary, surface utilities, or extensive
scripting.
This work was supported by Colin Moughton, at Strix
Multi-region PIMPLE controls have been applied to the chtMultiRegionFoam
solver, and a transonic option has been implemented.
The new PIMPLE controls let the solver operate SIMPLE mode. The
utilisation of library solution and convergence control functionality
has significantly reduced the amount of code in the solver. The
chtMultiRegionSimpleFoam solver has also been made obsolete, and has
therefore been removed.
A few changes will be necessary to convert an existing
chtMultiRegionSimpleFoam case to chtMultiRegionFoam. All the SIMPLE
sub-dictionaries in the system/<regions>/fvSolution will need to be
renamed PIMPLE. The system/fvSolution file will also need an empty
PIMPLE sub-dictionary. In addition, additional "<variable>Final" solver
and relaxation entries will be needed. For a steady case, adding a
wildcard ending, ".*", to the variable names should be sufficient.
Solution parameters appropriate for a steady case are shown below:
solvers
{
"p_rgh.*"
{
solver GAMG;
tolerance 1e-7;
relTol 0.01;
smoother DIC;
maxIter 10;
}
"(U|h|e|k|epsilon).*"
{
solver PBiCGStab;
preconditioner DILU;
tolerance 1e-7;
relTol 0.1;
}
}
PIMPLE
{
// ...
}
relaxationFactors
{
fields
{
"p_rgh.*" 0.7;
}
equations
{
"U.*" 0.5;
"(h|e).*" 0.3;
"(k|epsilon).*" 0.2;
}
}
This work was supported by Fabian Buelow, at Evonik
Tobias Holzmann provided cases for testing the convergence controls
Using the noSlip boundary condition for rotating wall in an MRF region
interferes with post-processing by resetting the wall velocity to 0 rather than
preserving the value set by the MRF zone.
A pureMixture can now be specified in a reacting solver. This further
enhances compatibility between non-reacting and reacting solvers.
To achieve this, mixtures now have a typeName function of the same form
as the lower thermodyanmic models. In addition, to avoid name clashes,
the reacting thermo make macros have been split into those that create
entries on multiple selection tables, and those that just add to the
reaction thermo table.
When an OpenFOAM simulation runs in parallel, the data for decomposed fields and
mesh(es) has historically been stored in multiple files within separate
directories for each processor. Processor directories are named 'processorN',
where N is the processor number.
This commit introduces an alternative "collated" file format where the data for
each decomposed field (and mesh) is collated into a single file, which is
written and read on the master processor. The files are stored in a single
directory named 'processors'.
The new format produces significantly fewer files - one per field, instead of N
per field. For large parallel cases, this avoids the restriction on the number
of open files imposed by the operating system limits.
The file writing can be threaded allowing the simulation to continue running
while the data is being written to file. NFS (Network File System) is not
needed when using the the collated format and additionally, there is an option
to run without NFS with the original uncollated approach, known as
"masterUncollated".
The controls for the file handling are in the OptimisationSwitches of
etc/controlDict:
OptimisationSwitches
{
...
//- Parallel IO file handler
// uncollated (default), collated or masterUncollated
fileHandler uncollated;
//- collated: thread buffer size for queued file writes.
// If set to 0 or not sufficient for the file size threading is not used.
// Default: 2e9
maxThreadFileBufferSize 2e9;
//- masterUncollated: non-blocking buffer size.
// If the file exceeds this buffer size scheduled transfer is used.
// Default: 2e9
maxMasterFileBufferSize 2e9;
}
When using the collated file handling, memory is allocated for the data in the
thread. maxThreadFileBufferSize sets the maximum size of memory in bytes that
is allocated. If the data exceeds this size, the write does not use threading.
When using the masterUncollated file handling, non-blocking MPI communication
requires a sufficiently large memory buffer on the master node.
maxMasterFileBufferSize sets the maximum size in bytes of the buffer. If the
data exceeds this size, the system uses scheduled communication.
The installation defaults for the fileHandler choice, maxThreadFileBufferSize
and maxMasterFileBufferSize (set in etc/controlDict) can be over-ridden within
the case controlDict file, like other parameters. Additionally the fileHandler
can be set by:
- the "-fileHandler" command line argument;
- a FOAM_FILEHANDLER environment variable.
A foamFormatConvert utility allows users to convert files between the collated
and uncollated formats, e.g.
mpirun -np 2 foamFormatConvert -parallel -fileHandler uncollated
An example case demonstrating the file handling methods is provided in:
$FOAM_TUTORIALS/IO/fileHandling
The work was undertaken by Mattijs Janssens, in collaboration with Henry Weller.
