SLGThermo has been moved to lagrangian, which still depends on it, pending
complete removal and replacement with a more rational interface to the carrier
phase thermodynamics.
The new fvModels is a general interface to optional physical models in the
finite volume framework, providing sources to the governing conservation
equations, thus ensuring consistency and conservation. This structure is used
not only for simple sources and forces but also provides a general run-time
selection interface for more complex models such as radiation and film, in the
future this will be extended to Lagrangian, reaction, combustion etc. For such
complex models the 'correct()' function is provided to update the state of these
models at the beginning of the PIMPLE loop.
fvModels are specified in the optional constant/fvModels dictionary and
backward-compatibility with fvOption is provided by reading the
constant/fvOptions or system/fvOptions dictionary if present.
The new fvConstraints is a general interface to optional numerical constraints
applied to the matrices of the governing equations after construction and/or to
the resulting field after solution. This system allows arbitrary changes to
either the matrix or solution to ensure numerical or other constraints and hence
violates consistency with the governing equations and conservation but it often
useful to ensure numerical stability, particularly during the initial start-up
period of a run. Complex manipulations can be achieved with fvConstraints, for
example 'meanVelocityForce' used to maintain a specified mean velocity in a
cyclic channel by manipulating the momentum matrix and the velocity solution.
fvConstraints are specified in the optional system/fvConstraints dictionary and
backward-compatibility with fvOption is provided by reading the
constant/fvOptions or system/fvOptions dictionary if present.
The separation of fvOptions into fvModels and fvConstraints provides a rational
and consistent separation between physical and numerical models which is easier
to understand and reason about, avoids the confusing issue of location of the
controlling dictionary file, improves maintainability and easier to extend to
handle current and future requirements for optional complex physical models and
numerical constraints.
A population balance suffix after the phase suffix makes determining the
phase for a given name more complex. The additional suffix is also
unnecessary as a phase can only ever belong to one population balance,
so the phase name alone uniquely idetifies the grouping.
Patch contributed by Institute of Fluid Dynamics,
Helmholtz-Zentrum Dresden - Rossendorf (HZDR)
A modified Arrhenius reaction rate given by:
k = (A * T^beta * exp(-Ta/T))*a
Where a is the phase surface area per unit volume. The name of the phase is
specified by the user.
Example usage:
oxidationAtSurface
{
type irreversiblePhaseSurfaceArrhenius;
reaction "O2^0 + TiCl4 = TiO2_s + 2Cl2";
A 4.9e1; // The pre-exponential factor is in units
// equal to that in the usual volumetric
// reaction rate **divided by length**, as
// the Arrhenius expression is taken to give
// rate per unit area, not per unit volume
beta 0.0;
Ta 8993;
phase particles;
}
This reaction has been applied to the titaniaSynthesisSurface tutorial,
which avoids the need for explicit caching of the surface area density
field.
This function gives a value of one during a user-specified duration, and
zero at all other times. It is useful for defining the time range in
which an injection or ignition heat source or similar operates.
Example usage, scaling a value:
<name>
{
type scale;
scale squarePulse;
start 0;
duration 1;
value 100;
}
This function has been utilised in a number of tutorial fvOption
configurations to provide a specific window in which the fvOption is
applied. This was previously achieved by "timeStart" and "duration"
controls hard coded into the fvOptions themselves.
This fvOption applies a mass source to the continuity equation and to
all field equations.
Example usage:
massSource
{
type massSource;
selectionMode cellSet;
cellSet massSource;
massFlowRate 1e-4;
fieldValues
{
U (10 0 0);
T 350;
k 0.375;
epsilon 14.855;
}
}
Values should be provided for all solved for fields. Warnings will be
issued if values are not provided for fields for which transport equations
are solved. Warnings will also be issued if values are provided for fields
which are not solved for.
A number of fvOptions that apply to a user-derined field can now
automatically work what primitive type they apply to. These options can
apply to any field type, and in some cases even multiple fields of
differing type. Example usage of the options to which this change
applies are shown below:
codedSource1
{
type codedSource;
name codedSource1;
field h;
...
}
fixedValueConstraint1
{
type fixedValueConstraint;
fieldValues
{
R (1 0 0 1 0 1);
epsilon 150;
}
...
}
phaseLimitStabilization11
{
type phaseLimitStabilization;
field sigma.liquid;
...
}
Previously to apply to a given type, these options had to be selected
with the name of the type prepended to the option name (e.g., "type
symmTensorPhaseLimitStabilization;") and those that operated on multiple
fields were restricted to those fields being of the same type.
A number of other options have had improvements made to their handling
of user specification of fields. Where possible, the option will now
attempt to work out what field the option applies to automatically. The
following options, therefore, no longer require "field" or "fields"
entries:
actuationDiskSource
buoyancyEnergy
buoyancyForce
meanVelocityForce
rotorDiskSource
volumeFractionSource
constantHeatTransfer
function2HeatTransfer
variableHeatTransfer
Non-standard field names can be overridden in the same way as in
boundary conditions; e.g., the velocity name can be overridden with a "U
<UName>;" entry if it does not have the default name, "U". The name of
the energy field is now always determined from the thermodynamics
model and should always be correct. Some options that can be applied to
an individual phase also support a "phase <phaseName>;" entry;
fvOptions field-name handling has been rewritten to increase its
flexibility and to improve warning messages. The flexibility now allows
for options that apply to all fields, or all fields of a given phase,
rather than being limited to a specific list of field names. Messages
warning about options that have not been applied now always print just
once per time-step.
Vertices are generated using run time compilation functionality.
File duplication avoided by placement in:
tutorials/resources/blockMesh/sloshingTank2D
tutorials/resources/blockMesh/sloshingTank3D
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.
Mesh-motion with or without topology change or AMI is now supported in
multiphaseEulerFoam for both cell- and face-momentum algorithms.
The new tutorial case mixerVesselAMI2D is provided which is the AMI version of
the 4-phase MRF mixerVessel2D case. It is setup with the cell-momentum
algorithm but also runs fine with the face-momentum algorithm although the
results are noticeably less accurate, particularly when the case is run
single-phase and compared directly with those from pimpleFoam.
Further testing is in progress.
I2D/constant/thermophysicalProperties.water
The phase-change functionality in interPhaseChangeFoam has been generalised and
moved into the run-time selectable twoPhaseChange library included into
interFoam providing optional phase-change. The three cavitation models provided
in interPhaseChangeFoam are now included in the twoPhaseChange library and the
two interPhaseChangeFoam cavitation tutorials updated for interFoam.
interPhaseChangeFoam has been replaced by a user redirection script which prints
the following message:
The interPhaseChangeFoam solver has solver has been replaced by the more general
interFoam solver, which now supports phase-change using the new twoPhaseChange
models library.
To run with with phase-change create a constant/phaseChangeProperties dictionary
containing the phase-change model specification, e.g.
phaseChangeModel SchnerrSauer;
pSat 2300; // Saturation pressure
See the following cases for an example converted from interPhaseChangeFoam:
$FOAM_TUTORIALS/multiphase/interFoam/laminar/cavitatingBullet
$FOAM_TUTORIALS/multiphase/interFoam/RAS/propeller
End points of topoSet cylinder sources should now be specified as
"point1" and "point2", which is consistent with other parts of the code.
The previous keywords, "p1" and "p2" have been retained for backwards
compatibility but may be removed in future.
It is better to not select and instantiate a model, fvOption etc. than to create
it and set it inactive as the creation process requires reading of settings,
parameters, fields etc. with all the associated specification and storage
without being used. Also the incomplete implementation added a lot of
complexity in the low-level operation of models introducing a significant
maintenance overhead and development overhead for new models.
TableBase, TableFile and Table now combined into a single simpler Table class
which handle both the reading of embedded and file data using the generalised
TableReader. The new EmbeddedTableReader handles the embedded data reading
providing the functionality of the original Table class within the same
structure that can read the data from separate files.
The input format defaults to 'embedded' unless the 'file' entry is present and
the Table class is added to the run-time selection table under the name 'table'
and 'tableFile' which provides complete backward comparability. However it is
advisable to migrate cases to use the new 'table' entry and all tutorial cases
have been updated.
using Function1 and supporting all the standard Function1s including tabulated
and coded.
tutorials/multiphase/interFoam/laminar/sloshingTank3D6DoF updated to use
sixDoFMotion.
and renamed defaultSpecie as its mass fraction is derived from the sum of the
mass fractions of all other species and it need not be inert but must be present
everywhere, e.g. N2 in air/fuel combustion which can be involved in the
production of NOx.
The previous name inertSpecie in thermophysicalProperties is supported for
backward compatibility.
This tutorial demonstrates the use of the population balance modeling
capability of multiphaseEulerFoam for the case of a vertical pipe. It
superseeds all bubbleColumnPolydisperse cases, which have been removed.
Patch contributed by Institute of Fluid Dynamics,
Helmholtz-Zentrum Dresden - Rossendorf (HZDR)
Expanded the documentation and updated the mean free path calculation
Patch contributed by Institute of Fluid Dynamics,
Helmholtz-Zentrum Dresden - Rossendorf (HZDR)
Optional switches "splitPhaseFlux" and "meanFluxReference" are now provided and
can be set true in fvSolution e.g.
solvers
{
"alpha.*"
{
nAlphaCorr 1;
nAlphaSubCycles 2;
splitPhaseFlux true;
meanFluxReference true;
}
.
.
.
to reinstate the previous form of phase flux limiters in which the mean and
phase flux differences are interpolated separately and the limited correction
referenced to the mean rather than phase flux. This form of discretisation and
limiting is more aggressive than the latest version and hence less accurate but
it is hoped that the latest form of limitSum will handle the boundedness at the
upper limit reliably allowing the new more accurate limiters to be used for most
if not all multiphase simulations.
Most fvOptions change the state of the fields and equations they are applied to
but do not change internal state so it makes more sense that the interface is
const, consistent with MeshObjects. For the few fvOptions which do maintain a
changing state the member data is now mutable.
foamDictionary executions are now wrapped by runApplication like any
other execution so that they do not print during a test loop.
foamDictionary does not produce a conforming log, however, so
log.foamDictionary has been filtered out of the formation of the test
loop report so that false failures are not reported.
The new optional 'slash' scoping syntax is now the default and provides a more
intuitive and flexible syntax than the previous 'dot' syntax, corresponding to
the common directory/file access syntax used in UNIX, providing support for
reading entries from other dictionary files.
In the 'slash' syntax
'/' is the scope operator
'../' is the parent dictionary scope operator
'!' is the top-level dictionary scope operator
Examples:
internalField 3.4;
active
{
type fixedValue;
value.air $internalField;
}
inactive
{
type anotherFixedValue;
value $../active/value.air;
anotherValue $!active/value.air;
sub
{
value $../../active/value.air;
anotherValue $!active/value.air;
}
}
"U.*"
{
solver GAMG;
}
e.air
{
$U.air;
}
external
{
value $testSlashDict2!active/value.air;
}
active2
{
$testSlashDict2!active;
}
If there is a part of the keyword before the '!' then this is taken to be the
file name of the dictionary from which the entry will be looked-up using the
part of the keyword after the '!'. For example given a file testSlashDict containing
internalField 5.6;
active
{
type fixedValue;
value.air $internalField;
}
entries from it can be read directly from another file, e.g.
external
{
value $testSlashDict2!active/value.air;
}
active2
{
$testSlashDict2!active;
}
which expands to
external
{
value 5.6;
}
active2
{
type fixedValue;
value.air 5.6;
}
These examples are provided in applications/test/dictionary.
The the default syntax can be changed from 'slash' to 'dot' in etc/controlDict
to revert to the previous behaviour:
OptimisationSwitches
{
.
.
.
// Default dictionary scoping syntax
inputSyntax slash; // Change to dot for previous behaviour
}
or within a specific dictionary by adding the entry
See applications/test/dictionary/testDotDict.
