The MomentumTransportModels library now builds of a standard set of
phase-incompressible and phase-compressible models. This replaces most
solver-specific builds of these models.
This has been made possible by the addition of a new
"dynamicTransportModel" interface, from which all transport classes used
by the momentum transport models now derive. For the purpose of
disambiguation, the old "transportModel" has also been renamed
"kinematicTransportModel".
This change has been made in order to create a consistent definition of
phase-incompressible and phase-compressible MomentumTransportModels,
which can then be looked up by functionObjects, fvModels, and similar.
Some solvers still build specific momentum transport models, but these
are now in addition to the standard set. The solver does not build all
the models it uses.
There are also corresponding centralised builds of phase dependent
ThermophysicalTransportModels.
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.
Usage
\table
Property | Description | Required | Default value
type | Type name: forces | yes |
log | Write force data to standard output | no | no
patches | Patches included in the forces calculation | yes |
p | Pressure field name | no | p
U | Velocity field name | no | U
rho | Density field name (see below) | no | rho
phase | Phase name for phase-fraction | no |
CofR | Centre of rotation (see below) | no |
directForceDensity | Force density supplied directly (see below)|no|no
fD | Name of force density field (see below) | no | fD
\endtable
with the optional 'phase' entry the corresponding phase-fraction is used to
filter the surfaces forces for that phase.
setTimeStep is now compatible with a 'writeControl adjustableRunTime;'
setting in the systemControlDict. If 'adjustableRunTime' is selected
then the time-step values set by this function object will not be
exactly as specified, but write intervals will be matched exactly.
All function object time adjustment is now done during the execute
methods, so the specific setTimeStep hooks have been removed.
All function objects now re-read as a result of run-time modifications
to the system/controlDict.
Function objects that write log files (via the logFiles class) will now
generate a new postProcessing/<funcName>/<time> directory as a result of
either restart or run-time modification. Log files will therefore never
be overwritten by restart or run-time modification, except for when a
case is restarted at the same time as a previous execution (e.g.,
repeated runs at the start time).
If the surfaceFieldValue function object is used to compute an
area-normal average or integral of a vector quantity, the result will
now be correctly written out as a scalar.
Previously surfaceFieldValue was limited to writing the same type as the
input field. A vector area-normal average or integral therefore had to
be written out as a vector. This was done by setting the x component to
the result, and the y and z components to zero. This was considered to
be counter-intuitive.
A volumetric flow rate through a tri-surface can now be obtained using
the volumetricFlowRateTriSurface preconfigured function object, using
the following entry in system/controlDict:
fuctions
{
#includeFunc "volumetricFlowRateTriSurface(name=surface.stl)"
}
Where "surface.stl" is a tri-surface file in the constant/triSurface
directory. An example of this has been added to the
incompressible/pimpleFoam/RAS/impeller tutorial case.
Note that when possible, it is preferable to use the flowRatePatch or
flowRateFaceZone functions, as these make direct use of the flux and
therefore report a value that is exactly that computed by the solver.
volumetricFlowRateTriSurface, by contrast, does interpolation of the
velocity field which introduces error.
In addition, a minor fix has been made to the underlying
surfaceFieldValue function object so that it does not need a zone/set
name when values on a searchable surface are requested.
Description
Transforms the specified velocity field into a
cylindrical polar coordinate system or back to Cartesian.
Example of function object specification to convert the velocity field U
into cylindrical polar coordinates before averaging and returning the
average to Cartesian coordinates:
\verbatim
cartesianToCylindrical
{
type cylindrical;
libs ("libfieldFunctionObjects.so");
origin (0 0 0);
axis (0 0 1);
field U;
writeControl outputTime;
writeInterval 1;
}
#includeFunc fieldAverage(cylindrical(U))
cylindricalToCartesian
{
type cylindrical;
libs ("libfieldFunctionObjects.so");
origin (0 0 0);
axis (0 0 1);
field cylindrical(U)Mean;
toCartesian true;
result UMean;
writeControl outputTime;
writeInterval 1;
}
\endverbatim
This is particularly useful for cases with rotating regions, e.g. mixer
vessels with AMI.
See tutorials/incompressible/pimpleFoam/laminar/mixerVesselAMI2D
Description
Updates the writeInterval as a Function1 of time.
Examples of function object specification:
\verbatim
setWriteInterval
{
type setWriteInterval;
libs ("libutilityFunctionObjects.so");
writeInterval table
(
(0 0.005)
(0.1 0.005)
(0.1001 0.01)
(0.2 0.01)
(0.2001 0.02)
);
}
\endverbatim
will cause results to be written every 0.005s between 0 and 0.1s, every
0.01s between 0.1 and 0.2s and every 0.02s thereafter.
Following functionality added:
- support of dimensional inputs
- run time selection mechanism of HTC model (kappaEff, ReynoldsAnalogy)
- kappaEff has now two options for calculating HTC (with/without characteristic length)
- Reynolds Analogy estimation for HTC
- integrated HTC replaced with an average log output
Description
Calculates and writes the estimated heat transfer coefficient at wall
patches as the volScalarField field.
All wall patches are included by default; to restrict the calculation to
certain patches, use the optional 'patches' entry.
The models are selected run time by model entry. For detailed description
look at the header file for specific model under
wallHeatTransferCoeffModels.
Example of function object specification:
\verbatim
kappaEff1
{
type wallHeatTransferCoeff;
libs ("libfieldFunctionObjects.so");
model kappaEff;
...
region fluid;
patches (".*Wall");
rho 1.225;
Cp 1005;
Prl 0.707;
Prt 0.9;
}
\endverbatim
\verbatim
kappaEff2
{
type wallHeatTransferCoeff;
libs ("libfieldFunctionObjects.so");
model kappaEff;
...
region fluid;
patches (".*Wall");
rho 1.225;
Cp 1005;
Prl 0.707;
Prt 0.9;
Lchar 0.001;
}
\endverbatim
\verbatim
ReynoldsAnalogy1
{
type wallHeatTransferCoeff;
libs ("libfieldFunctionObjects.so");
model ReynoldsAnalogy;
...
region fluid;
patches (".*Wall");
rho 1.225;
Cp 1005;
Uref 1.0;
}
\endverbatim
Note
Writing field 'wallHeatTransferCoeff' is done by default, but it can be
overridden by defining an empty \c objects list. For details see
writeLocalObjects.
The streamLines function object now writes out "age" by default. This is
calculated as the total integration time from the starting point of the
streamline. This value can be negative if tracking is performed in the
reverse direction. Writing "age" can be deactivated by means of a
"writeAge no;" entry in the function object specification.
The wallHeatFlux field is now intensive with units [W/m^2]
and the minimum, maximum, patch integrated Q [W] and patch average q [W-m^2]
are written in postProcessing/wallHeatFlux/<time>/wallHeatFlux.dat
This avoids attempting to write temporary fields before they have been created.
The executeAtStart can be set to 'yes' in the writeObjects dictionary or the
functions
{
#includeFunc writeObjects(executeAtStart = yes, <field1>, <field2>...)
}
This is a slight modification of the previous commit. All cached
temporary fields are now written to disk with the name enclosed by
"tmp<...>". This still allows for automatically constructed
field names to be read by paraFoam and other post-processing tools. It
also creates a consistent convention for naming all cached temporary
fields that are written to disk.
for example
cacheTemporaryObjects
(
"((1|((1|(1|A(U)))-H(1)))-(1|A(U)))"
);
functions
{
#includeFunc writeObjects(regExp=off, "((1|((1|(1|A(U)))-H(1)))-(1|A(U)))")
}
writes the temporary field with the name
"expr((1|((1|(1|A(U)))-H(1)))-(1|A(U)))" so that it can be read by paraFoam and
other post-processing tools.
such that div(q()) = divq(...)
and div(j()) = divj(...)
to unsure consistency between the reported heat (e.g. by the wallHeatFlux
functionObject) and mass fluxes and those used in the energy and specie
mass-fraction equations.
and changed to be an energy implicit correction to a temperature gradient
based heat-flux. This formulation is both energy conservative and temperature
consistent.
The wallHeatFlux functionObject has been updated to use a consistent heat-flux
from the heSolidThermo.
The standard set of Lagrangian clouds are now selectable at run-time.
This means that a solver that supports Lagrangian modelling can now use
any type of cloud (with some restrictions). Previously, solvers were
hard-coded to use specific cloud modelling. In addition, a cloud-list
structure has been added so that solvers may select multiple clouds,
rather than just one.
The new system is controlled as follows:
- If only a single cloud is required, then the settings for the
Lagrangian modelling should be placed in a constant/cloudProperties
file.
- If multiple clouds are required, then a constant/clouds file should be
created containing a list of cloud names defined by the user. Each
named cloud then reads settings from a corresponding
constant/<cloudName>Properties file. Clouds are evolved sequentially
in the order in which they are listed in the constant/clouds file.
- If no clouds are required, then the constant/cloudProperties file and
constant/clouds file should be omitted.
The constant/cloudProperties or constant/<cloudName>Properties files are
the same as previous cloud properties files; e.g.,
constant/kinematicCloudProperties or constant/reactingCloud1Properties,
except that they now also require an additional top-level "type" entry
to select which type of cloud is to be used. The available options for
this entry are:
type cloud; // A basic cloud of solid
// particles. Includes forces,
// patch interaction, injection,
// dispersion and stochastic
// collisions. Same as the cloud
// previously used by
// rhoParticleFoam
// (uncoupledKinematicParticleFoam)
type collidingCloud; // As "cloud" but with resolved
// collision modelling. Same as the
// cloud previously used by DPMFoam
// and particleFoam
// (icoUncoupledKinematicParticleFoam)
type MPPICCloud; // As "cloud" but with MPPIC
// collision modelling. Same as the
// cloud previously used by
// MPPICFoam.
type thermoCloud; // As "cloud" but with
// thermodynamic modelling and heat
// transfer with the carrier phase.
// Same as the limestone cloud
// previously used by
// coalChemistryFoam.
type reactingCloud; // As "thermoCloud" but with phase
// change and mass transfer
// coupling with the carrier
// phase. Same as the cloud
// previously used in fireFoam.
type reactingMultiphaseCloud; // As "reactingCloud" but with
// particles that contain multiple
// phases. Same as the clouds
// previously used in
// reactingParcelFoam and
// simpleReactingParcelFoam and the
// coal cloud used in
// coalChemistryFoam.
type sprayCloud; // As "reactingCloud" but with
// additional spray-specific
// collision and breakup modelling.
// Same as the cloud previously
// used in sprayFoam and
// engineFoam.
The first three clouds are not thermally coupled, so are available in
all Lagrangian solvers. The last four are thermally coupled and require
access to the carrier thermodynamic model, so are only available in
compressible Lagrangian solvers.
This change has reduced the number of solvers necessary to provide the
same functionality; solvers that previously differed only in their
Lagrangian modelling can now be combined. The Lagrangian solvers have
therefore been consolidated with consistent naming as follows.
denseParticleFoam: Replaces DPMFoam and MPPICFoam
reactingParticleFoam: Replaces sprayFoam and coalChemistryFoam
simpleReactingParticleFoam: Replaces simpleReactingParcelFoam
buoyantReactingParticleFoam: Replaces reactingParcelFoam
fireFoam and engineFoam remain, although fireFoam is likely to be merged
into buoyantReactingParticleFoam in the future once the additional
functionality it provides is generalised.
Some additional minor functionality has also been added to certain
solvers:
- denseParticleFoam has a "cloudForceSplit" control which can be set in
system/fvOptions.PIMPLE. This provides three methods for handling the
cloud momentum coupling, each of which have different trade-off-s
regarding numerical artefacts in the velocity field. See
denseParticleFoam.C for more information, and also bug report #3385.
- reactingParticleFoam and buoyantReactingParticleFoam now support
moving mesh in order to permit sharing parts of their implementation
with engineFoam.
The reactingtTwoPhaseEulerFoam solver has been replaced by the more general
multiphaseEulerFoam solver which supports two-phase and multiphase systems
containing fluid and stationary phases, compressible or incompressible, with
heat and mass transfer, reactions, size distribution and all the usual phase
interaction and transfer models.
All reactingtTwoPhaseEulerFoam tutorials have been ported to multiphaseEulerFoam
to demonstrate two-phase capability with a wide range of phase and
phase-interaction models.
When running with two-phases the optional referencePhase entry in
phaseProperties can be used to specify which phase fraction should not be
solved, providing compatibility with reactingtTwoPhaseEulerFoam, see
tutorials/multiphase/multiphaseEulerFoam/RAS/fluidisedBed
tutorials/multiphase/multiphaseEulerFoam/laminar/bubbleColumn
for examples.
Description
Stops the run when the specified clock time in second has been reached
and optionally write results before stopping.
The following actions are supported:
- noWriteNow
- writeNow
- nextWrite (default)
Examples of function object specification:
\verbatim
stop
{
type stopAtClockTime;
libs ("libutilityFunctionObjects.so");
stopTime 10;
action writeNow;
}
\endverbatim
will stop the run at the next write after the file "stop" is created in the
case directory.
Usage
\table
Property | Description | Required | Default value
type | type name: stopAtClockTime | yes |
stopTime | Maximum elapsed time [s] | yes |
action | Action executed | no | nextWrite
\endtable
By default the case stops following the next write but stopping immediately with
or without writing are also options.
The stopAtFile functionObject derived from stopAt stops the run when a file
predefined file is created in the case directory:
Description
Stops the run when the specified file is created in the case directory.
The default name of the trigger file is \c $FOAM_CASE/<name> where \c
<name> is the name of the functionObject entry and the default action is \c
nextWrite.
Currently the following action types are supported:
- noWriteNow
- writeNow
- nextWrite
Examples of function object specification:
\verbatim
stop
{
type stopAtFile;
libs ("libutilityFunctionObjects.so");
}
\endverbatim
will stop the run at the next write after the file "stop" is created in the
case directory.
\verbatim
stop
{
type stopAtFile;
libs ("libutilityFunctionObjects.so");
file "$FOAM_CASE/stop";
action writeNow;
}
\endverbatim
will write the fields and stop the run when the file "stop" is created in
the case directory.
Usage
\table
Property | Description | Required | Default value
type | type name: stopAtFile | yes |
file | Trigger file path name | no | $FOAM_CASE/<name>
action | Action executed | no | nextWrite
\endtable
