- Use on/off vs longer compressed/uncompressed.
For consistency, replaced yes/no with on/off.
- Avoid the combination of binary/compressed,
which is disallowed and provokes a warning anyhow
Evolves an electrical potential equation
\f[
\grad \left( \sigma \grad V \right)
\f]
where \f$ V \f$ is electrical potential and \f$\sigma\f$ is the
electrical current
To provide a Joule heating contribution according to:
Differential form of Joule heating - power per unit volume:
\f[
\frac{d(P)}{d(V)} = J \cdot E
\f]
where \f$ J \f$ is the current density and \f$ E \f$ the electric
field.
If no magnetic field is present:
\f[
J = \sigma E
\f]
The electric field given by
\f[
E = \grad V
\f]
Therefore:
\f[
\frac{d(P)}{d(V)} = J \cdot E
= (sigma E) \cdot E
= (sigma \grad V) \cdot \grad V
\f]
Usage
Isotropic (scalar) electrical conductivity
\verbatim
jouleHeatingSourceCoeffs
{
anisotropicElectricalConductivity no;
// Optionally specify the conductivity as a function of
// temperature
// Note: if not supplied, this will be read from the time
// directory
sigma table
(
(273 1e5)
(1000 1e5)
);
}
\endverbatim
Anisotropic (vectorial) electrical conductivity
jouleHeatingSourceCoeffs
{
anisotropicElectricalConductivity yes;
coordinateSystem
{
type cartesian;
origin (0 0 0);
coordinateRotation
{
type axesRotation;
e1 (1 0 0);
e3 (0 0 1);
}
}
// Optionally specify sigma as a function of temperature
//sigma (31900 63800 127600);
//
//sigma table
//(
// (0 (0 0 0))
// (1000 (127600 127600 127600))
//);
}
Where:
\table
Property | Description | Required | Default
value
T | Name of temperature field | no | T
sigma | Electrical conductivity as a function of
temperature |no|
anisotropicElectricalConductivity | Anisotropic flag | yes |
\endtable
The electrical conductivity can be specified using either:
- If the \c sigma entry is present the electrical conductivity is
specified
as a function of temperature using a Function1 type
- If not present the sigma field will be read from file
- If the anisotropicElectricalConductivity flag is set to 'true',
sigma
should be specified as a vector quantity
For example the actuationDiskSource fvOption may now be specified
disk1
{
type actuationDiskSource;
fields (U);
selectionMode cellSet;
cellSet actuationDisk1;
diskDir (1 0 0); // Orientation of the disk
Cp 0.386;
Ct 0.58;
diskArea 40;
upstreamPoint (581849 4785810 1065);
}
rather than
disk1
{
type actuationDiskSource;
active on;
actuationDiskSourceCoeffs
{
fields (U);
selectionMode cellSet;
cellSet actuationDisk1;
diskDir (1 0 0); // Orientation of the disk
Cp 0.386;
Ct 0.58;
diskArea 40;
upstreamPoint (581849 4785810 1065);
}
}
but this form is supported for backward compatibility.
The standard naming convention for heat flux is "q" and this is used for the
conductive and convective heat fluxes is OpenFOAM. The use of "Qr" for
radiative heat flux is an anomaly which causes confusion, particularly for
boundary conditions in which "Q" is used to denote power in Watts. The name of
the radiative heat flux has now been corrected to "qr" and all models, boundary
conditions and tutorials updated.
The fundamental properties provided by the specie class hierarchy were
mole-based, i.e. provide the properties per mole whereas the fundamental
properties provided by the liquidProperties and solidProperties classes are
mass-based, i.e. per unit mass. This inconsistency made it impossible to
instantiate the thermodynamics packages (rhoThermo, psiThermo) used by the FV
transport solvers on liquidProperties. In order to combine VoF with film and/or
Lagrangian models it is essential that the physical propertied of the three
representations of the liquid are consistent which means that it is necessary to
instantiate the thermodynamics packages on liquidProperties. This requires
either liquidProperties to be rewritten mole-based or the specie classes to be
rewritten mass-based. Given that most of OpenFOAM solvers operate
mass-based (solve for mass-fractions and provide mass-fractions to sub-models it
is more consistent and efficient if the low-level thermodynamics is also
mass-based.
This commit includes all of the changes necessary for all of the thermodynamics
in OpenFOAM to operate mass-based and supports the instantiation of
thermodynamics packages on liquidProperties.
Note that most users, developers and contributors to OpenFOAM will not notice
any difference in the operation of the code except that the confusing
nMoles 1;
entries in the thermophysicalProperties files are no longer needed or used and
have been removed in this commet. The only substantial change to the internals
is that species thermodynamics are now "mixed" with mass rather than mole
fractions. This is more convenient except for defining reaction equilibrium
thermodynamics for which the molar rather than mass composition is usually know.
The consequence of this can be seen in the adiabaticFlameT, equilibriumCO and
equilibriumFlameT utilities in which the species thermodynamics are
pre-multiplied by their molecular mass to effectively convert them to mole-basis
to simplify the definition of the reaction equilibrium thermodynamics, e.g. in
equilibriumCO
// Reactants (mole-based)
thermo FUEL(thermoData.subDict(fuelName)); FUEL *= FUEL.W();
// Oxidant (mole-based)
thermo O2(thermoData.subDict("O2")); O2 *= O2.W();
thermo N2(thermoData.subDict("N2")); N2 *= N2.W();
// Intermediates (mole-based)
thermo H2(thermoData.subDict("H2")); H2 *= H2.W();
// Products (mole-based)
thermo CO2(thermoData.subDict("CO2")); CO2 *= CO2.W();
thermo H2O(thermoData.subDict("H2O")); H2O *= H2O.W();
thermo CO(thermoData.subDict("CO")); CO *= CO.W();
// Product dissociation reactions
thermo CO2BreakUp
(
CO2 == CO + 0.5*O2
);
thermo H2OBreakUp
(
H2O == H2 + 0.5*O2
);
Please report any problems with this substantial but necessary rewrite of the
thermodynamic at https://bugs.openfoam.org
Henry G. Weller
CFD Direct Ltd.
e.g. in tutorials/heatTransfer/buoyantSimpleFoam/externalCoupledCavity/0/T
hot
{
type externalCoupledTemperature;
commsDir "${FOAM_CASE}/comms";
file "data";
initByExternal yes;
log true;
value uniform 307.75; // 34.6 degC
}
Previously both 'file' and 'fileName' were used inconsistently in different
classes and given that there is no confusion or ambiguity introduced by using
the simpler 'file' rather than 'fileName' this change simplifies the use and
maintenance of OpenFOAM.
Bounding thermo.rho in rhoPorousSimpleFoam.
Changing initial time step in externalSolarLoad tutorial.
Commenting out momemtun source term in steamInjection which causes problems
- In the corner case with few faces or points, the normal List I/O
results in a compact list representation.
This is less than desirable for external programs with simple
line-based parsers.
- Write exactly the following
*Faces*
// Patch: <word-Region> <word-Patch>
<int-nFaces>
(
<int-faceSize>(<int> .. <int>)
...
)
*Points*
// Patch: <word-Region> <word-Patch>
<int-nPoints>
(
(<float-x> <float-y> <float-z>)
...
)
STYLE: only use serial form of createExternalCoupledPatchGeometry in tutorial
- less confusing for the user, who wonders why it is being done twice.
using a run-time selectable preconditioner
References:
Van der Vorst, H. A. (1992).
Bi-CGSTAB: A fast and smoothly converging variant of Bi-CG
for the solution of nonsymmetric linear systems.
SIAM Journal on scientific and Statistical Computing, 13(2), 631-644.
Barrett, R., Berry, M. W., Chan, T. F., Demmel, J., Donato, J.,
Dongarra, J., Eijkhout, V., Pozo, R., Romine, C. & Van der Vorst, H.
(1994).
Templates for the solution of linear systems:
building blocks for iterative methods
(Vol. 43). Siam.
See also: https://en.wikipedia.org/wiki/Biconjugate_gradient_stabilized_method
Tests have shown that PBiCGStab with the DILU preconditioner is more
robust, reliable and shows faster convergence (~2x) than PBiCG with
DILU, in particular in parallel where PBiCG occasionally diverges.
This remarkable improvement over PBiCG prompted the update of all
tutorial cases currently using PBiCG to use PBiCGStab instead. If any
issues arise with this update please report on Mantis: http://bugs.openfoam.org
