The pressure provided to the patch and cellSet property evaluation functions is
always that stored by the thermodynamics package as is the composition which is
provided internally; given that these functions are used in boundary conditions
to estimate changes in heat flux corresponding to changes in temperature only
there is no need for another pressure to be provided. In order that the
pressure and composition treatment are consistent and to maintain that during
future rationalisation of the handling of composition it makes sense to remove
this unnecessary pressure argument.
The chemistryModel and combustionModel do not change the thermodynamics directly
and should not require non-const access to it. In order to change the
thermodynamics model argument and stored references to const the specie "active"
flags in TDAC have been changed to mutable as this is not a direct change in the
thermodynamic state but a set of switches which allow the state to change
differently during the next thermodynamics update.
Function1 has been generalised in order to provide functionality
previously provided by some near-duplicate pieces of code.
The interpolationTable and tableReader classes have been removed and
their usage cases replaced by Function1. The interfaces to Function1,
Table and TableFile has been improved for the purpose of using it
internally; i.e., without user input.
Some boundary conditions, fvOptions and function objects which
previously used interpolationTable or other low-level interpolation
classes directly have been changed to use Function1 instead. These
changes may not be backwards compatible. See header documentation for
details.
In addition, the timeVaryingUniformFixedValue boundary condition has
been removed as its functionality is duplicated entirely by
uniformFixedValuePointPatchField.
In two phases, the turbulent dispersion force is modelled for a phase
pair as follows:
F12 = D12*grad(alpha1)
Where D12 is the turbulent dispersion coefficient between phases 1 and
2. This force is calculated equivalently whichever phase is chosen to be
phase 1 because the volume fractions are related by alpha1 = 1 - alpha2.
This means that F12 == - F21; i.e., the force in one phase equals the
reaction in the other.
In multiple phases, however, a force calculated in this way is no longer
consistent between phases, because the relationship between the volume
fractions no longer applies. The following form has been chosen instead.
F12 = D12*grad(alpha1/(alpha1 + alpha2))
I.e., rather than using the gradient of a phase directly, we use the
gradient of the phase within the two-phase sub-system associated with
the pair.
This reduces to the two-phase case above, and the models available in
the literature that are explicitly formulated for multiple phases can
also be expressed in this form.
Based on a patch contributed by Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden -
Rossendorf (HZDR) and VTT Technical Research Centre of Finland Ltd.
Integral evaluations have been implemented for all the ramp function1-s,
as well as the sine and square wave. Bounds handling has also been added
to the integration of table-type functions.
In addition, the sine wave "t0" paramater has been renamed "start" for
consistency with the ramp functions.
Description
Gunn (1978) correlation for fixed and fluidized beds with Re < 10^5
and continuous phase fraction between 0.35 and 1.
Reference:
\verbatim
Gunn, D. J. (1978).
Transfer of heat or mass to particles in fixed and fluidised beds.
International Journal of Heat and Mass Transfer, 21(4), 467-476.
\endverbatim
Based on code contributed by Alberto Passalacqua
Description
Calculates the thermal comfort quantities predicted mean vote (PMV) and
predicted percentage of dissatisfaction (PPD) based on DIN ISO EN 7730:2005.
Usage
\table
Property | Description | Required | Default value
clothing | The insulation value of the cloth | no | 0
metabolicRate | The metabolic rate | no | 0.8
extWork | The external work | no | 0
Trad | Radiation temperature | no | -1
relHumidity | Relative humidity of the air | no | 50
pSat | Saturation pressure of water | no | -1
tolerance | Residual control for the cloth temperature | no | 1e-5
maxClothIter | Maximum number of iterations | no | 0
meanVelocity | Use a constant mean velocity in the whole domain | no |\
false
\endtable
\table
Predicted Mean Vote (PMV) | evaluation
+ 3 | hot
+ 2 | warm
+ 1 | slightly warm
+ 0 | neutral
- 1 | slightly cool
- 2 | cool
- 3 | cold
\endtable
\verbatim
comfortAnalysis
{
type comfort;
libs ("libfieldFunctionObjects.so");
executeControl writeTime;
writeControl writeTime;
}
\endverbatim
The new tutorial case heatTransfer/buoyantSimpleFoam/comfortHotRoom is provided
to demonstrate the calculation of PMV and PPD using the comfort functionObject.
This work is based on code and case contributed by Tobias Holzmann.
Mass transfer rates now have a more comprehensive naming convention.
"dmdt" means a bulk/mixture transfer, whilst "dmidt" is for a
specie-specific transfer. "dmdt" implies a transfer into a phase, whilst
"dmdtf" means a transfer across an interface. Tables or lists of
transfers are denoted by pluralising the name with the suffix "s"; e.g.,
"dmdtfs". All registered mass transfer rate fields have names which
include the name of the sub-model or phase system which generated them.
The phaseTransfer models have been changed so that the mixture and the
specie-specific mass transfers are independent. This simplifies the
naming convention required for registering the resulting mass transfers
and reduces the amount of logic necessary in the phase system.
The inheritance pattern of the alphat wall functions has been altered so
that the code and parameters relating to phase change are reused, and so
that the base (the Jayatilleke wall function) more closely resembles the
library implementation. This should make it easier to remove it when the
library function is generalised enough to use it directly.
The phaseSystem::zero*Field construction functions have been removed as
their behaviour regarding registration was not clear, and in most
instances of their usage the GeometriField<...>::New methods are
similarly convenient.
This change extends phaseTransferModel and PhaseTransferPhaseSystem to
allow non-uniform specie transfer between phases.
A reactionDriven phaseTransfer model is added which represents change of
selected species from one phase to another due to a reaction occurring
within one of the phases.
Following the change, the reactionDriven nucleation models and the
phaseChange drift models in populationBalanceModel have been updated to
use the new functionality in PhaseTransferPhaseSystem. The
PopulationBalancePhaseSystem has been simplified significantly as a
result.
The functionality is demonstrated by a tutorial case simulating the
vapour phase synthesis of titania by titanium tetrachloride oxidation
where both nucleation and surface reactions models are active at the
same time.
Patch contributed by VTT Technical Research Centre of Finland Ltd and
Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden - Rossendorf (HZDR).
This is a modified Arrhenius reaction rate where the reaction rate is
multiplied by a surface area per unit volume.
The reaction rate is given by:
k = (A * T^beta * exp(-Ta/T))*a
Where a is the surface area per unit volume, the name of which is
specified by the user. This enables, for example, the reaction rate to
depend on the surface area concentration of catalyst particles.
Patch contributed by VTT Technical Research Centre of Finland Ltd and
Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden - Rossendorf (HZDR).
Surface area per unit volume is now available in the diameter models.
Storing the diameter and/or surface area per unit volume fields can now
be activated for any model by means of "storeD" and "storeA"
switches. If the underlying model already stores the field then the
switch is ignored.
Based on a patch contributed by VTT Technical Research Centre of Finland Ltd and
Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden - Rossendorf (HZDR).
A clause preventing solution of the density equation has been removed
from reactingParcelFoam and chtMultiRegionFoam, so that they are nore
consistent with other compressible solvers. In general, the density
equation is solved before the pimple loop is entered to make sure that
the flux and the density derivative are consistent during the first
pimple iteration.
to enable the calculation of the residence time for a fluid; mainly used in HVAC
analysis. E.g. residence time of air inside a ventilated room, see the new
tutorial roomResidenceTime.
Contributed by Tobias Holzmann
Rather than defining patches for all external block faces to provide name and
type use the defaultPatch entry to collect undefined faces into a single named
and typed patch, e.g.
defaultPatch
{
name walls;
type wall;
}
Description
Time-dependent external force restraint using Function1.
Usage
Example applying a constant force to the floatingObject:
restraints
{
force
{
type externalForce;
body floatingObject;
location (0 0 0);
force (100 0 0);
}
}
Based on code contributed by SeongMo Yeon
Resolves contribution request https://bugs.openfoam.org/view.php?id=3358
Description
Time-dependent external force restraint using Function1.
Usage
Example applying a constant force to the floatingObject:
restraints
{
force
{
type externalForce;
body floatingObject;
location (0 0 0);
force (100 0 0);
}
}
Based on code contributed by SeongMo Yeon
Resolves contribution request https://bugs.openfoam.org/view.php?id=3358
Description
A wrapper class to reverse any ramp function such that the result starts
from 1 decreasing to 0 from \c start over the \c duration and remaining at 0
thereafter.
Usage for scaling a vector:
\verbatim
<entryName>
{
scale
{
type reverseRamp;
ramp linearRamp;
start 0;
duration 10;
}
value
{
type sine;
frequency 10;
amplitude 1;
scale (1 0.1 0);
level (10 1 0);
}
}
\endverbatim
Based on code contributed by SeongMo Yeon
See https://bugs.openfoam.org/view.php?id=3358
Provides access to properties of the model and current state for complex and
time-dependent restraints.
Patch contributed by SeongMo Yeon
Resolves contribution https://bugs.openfoam.org/view.php?id=3345#c10787
Changed the interpolation of HbyA from
fvc::flux(rho*HbyA)
to
fvc::interpolate(rho)*fvc::flux(HbyA)
for consistency with the latest compressible p-U algorithm in rhoPimpleFoam.
For most cases this change does not affect the results but test on highly
compressible, transonic and supersonic cases have shown a small but clear
benefit in the new form.
The side surfaces in this tutorial have been made symmetry planes to
match the corresponding boundaries in the film region, and the top has
had its pressure condition changed to totalPressure. The case now runs
successfully to completion.
Previously the pressure-velocity boundary condition combination on the
non-film patches was incorrect in that in regions of outflow a pressure
value was not being specified. This resulted in divergence.
Cached temporary objects are now registered from the moment of
construction. This means it is possible to use them before they go out
of scope. Non-cached temporaries are not registered, as before.
The check for the existence of requested cached objects is now done
after function object evaluation. This means that caching can be done on
fields generated by the function objects themselves without generating
warning messages.
The above, however, means that if an object isn't successfully cached
and it's lookup in a function fails, then the warning will not be
generated before the lookup raises an error. This could make diagnosing
the reason for such a failure more difficult. To remedy this the content
of the warning (i.e., the list of objects that are available for
caching) has been added to the lookup error message if the looked up
name is on the caching list. The same level of logged information is
therefore retained in the event of caching and lookup failures.
All multi-specie solvers function on the assumption that the
mass-diffusivities of the different species are the same. A consequence
of this is that the diffusivities of energy and mass must be the same,
otherwise mass diffusivity results in unphysical temperature
fluctuations. This change enforces this requirement across all
multi-species solvers.
For the same reason, the turbulent Schmidt number has been removed from
the multi-component phase model in reactingEulerFoam. In order to obey
physical constraints this Schmidt number had to be exactly the same as
the Prandtl number. This condition is now enforced by the solver, rather
than relying on the input being correct.
By default most functionObjects now execute and write at the start-time except
those that perform averaging (fieldAverage, dsmcFields) which cannot be executed
until the end of the first time-step. There is also a new optional
functionObject dictionary entry "executeAtStart" which defaults to true but can
be set false if the execution and results of the functionObject are not required
or appropriate at the start-time.
A result of this change is that time logs of forces, sampling etc. now include a
values for time 0.
Description
Calculates the natural logarithm of the specified scalar field.
Performs \f$ln(max(x, a))\f$ where \f$x\f$ is the field and \f$a\f$ an
optional clip to handle 0 or negative \f$x\f$. Dimension checking can
optionally be suspended for this operation if \f$x\f$ is dimensioned.
Example of function object specification:
\verbatim
log1
{
type log;
libs ("libfieldFunctionObjects.so");
field p;
clip 1e-3;
checkDimensions no;
}
\endverbatim
or using \c postProcess
\verbatim
postProcess -func 'log(p, clip=1e-3, checkDimensions=no)'
\endverbatim
Usage
\table
Property | Description | Required | Default value
type | Type name: log | yes |
clip | Clip value | no |
checkDimensions | Dimension checking switch | no |
\endtable
Interface composition models are now specified in
constant/phaseProperties like so:
interfaceComposition.gas
(
(gas and water)
{
// ...
}
(gas and oil)
{
// ...
}
);
interfaceComposition.water
(
(water and gas)
{
// ...
}
// ...
);
// ...
I.e., the models associated with diffusive transfer within a phase
"<phase>" are specified in the list "interfaceComposition.<phase>".
Within the list, models are specified in unordered phase pairs
corresponding to the interface.
This replaces a system where models were specified in a single
interfaceComposition list, with the ordered pair entry "(<phase1> in
<phase2>)" meaning transfer within phase1 at the interface with phase2.
This ordered pair syntax is otherwise used for distinguishing between
continuous and dispersed phases. This dual meaning was considered
counter-intuitive. The new entries also more closely resemble the
associated two-resistance heat and mass transfer model specifications.
