This provides an extensible and run-time selectable framework to support complex
energy and specie transport models, in particular multi-component diffusion.
Currently only the Fourier for laminar and eddyDiffusivity for RAS and LES
turbulent flows are provided but the interface is general and the set of models
will be expanded in the near future.
The simplistic energy transport support in compressibleTurbulenceModels has been
abstracted and separated into the new ThermophysicalTransportModels library in
order to provide a more general interface to support complex energy and specie
transport models, in particular multi-component diffusion. Currently only the
Fourier for laminar and eddyDiffusivity for RAS and LES turbulent flows are
provided but the interface is general and the set of models will be expanded in
the near future.
The ThermalDiffusivity and EddyDiffusivity modelling layers remain in
compressibleTurbulenceModels but will be removed shortly and the alphat boundary
conditions will be moved to ThermophysicalTransportModels.
Following the generalisation of the TurbulenceModels library to support
non-Newtonian laminar flow including visco-elasticity and extensible to other
form of non-Newtonian behaviour the name TurbulenceModels is misleading and does
not properly represent how general the OpenFOAM solvers now are. The
TurbulenceModels now provides an interface to momentum transport modelling in
general and the plan is to rename it MomentumTransportModels and in preparation
for this the turbulenceProperties dictionary has been renamed momentumTransport
to properly reflect its new more general purpose.
The old turbulenceProperties name is supported for backward-compatibility.
These provide pressure boundary conditions suitable for use on
boundaries where the flow may reverse or on which the inlet or outlet
state is not known or well defined. The condition takes the following
form:
p = p0 + 0.5*Un*mag(Un)
In the case of exactly normal inlet velocity, this condition sets the
same pressure as the totalPressure condition. The pressure that is set
increases with increasing outlet velocity and decreases with increasing
inlet velocity. This makes it self-limiting and extremely stable in a
number of configurations which were not easily simulated previously. The
condition also does varies smoothly as the flux reverses, which also
aids stability.
The controls of this boundary condition are exactly the same as for the
totalPressure condition. Note, however, that "p0" is not necessarily the
total pressure any more. It is, in general, a reference pressure.
An example usage is as follows:
sides
{
type entrainmentPressure;
p0 100;
}
Additional flexibility for handling of field arguments has been extended
to dictionary lists of field settings, as well as word lists of field
names. This means that the following syntax is now supported:
postProcess -func "fieldAverage(p, U { prime2Mean on; }, T)"
postProcess -func "fieldAverage(fields=(p U { prime2Mean on; } T))"
Function object argument parsing now takes all "field", "fields" and
"objects" arguments and combines them into a single list of
fields/objects that the function should operate on. This means that the
following postProcess executions are now all equivalent and function as
expected:
postProcess -func "
flowRatePatch
(
name=outlet,
phi,
alphaRhoPhi.air,
alphaRhoPhi.particles
)"
postProcess -func "
flowRatePatch
(
name=outlet,
fields=(phi alphaRhoPhi.air alphaRhoPhi.particles)
)"
postProcess -func "
flowRatePatch
(
name=outlet,
objects=(phi),
alphaRhoPhi.air,
field=alphaRhoPhi.particles
)"
As are the following:
postProcess -func "mag(U.air)"
postProcess -func "mag(field=U.air)"
renaming the legacy keywords
RASModel -> model
LESModel -> model
laminarModel -> model
which is simpler and clear within the context in which they are specified, e.g.
RAS
{
model kOmegaSST;
turbulence on;
printCoeffs on;
}
rather than
RAS
{
RASModel kOmegaSST;
turbulence on;
printCoeffs on;
}
The old keywords are supported for backward compatibility.
The ability to specify the file name of the turbulenceProperties dictionary
during construction was added to support multi-phases but now that the handling
of the phase name extension has been completely rationalised and standardised
this complexity and code clutter is no longer used, needed or appropriate.
This significant improvement is flexibility of SemiImplicitSource required a
generalisation of the source specification syntax and all tutorials have been
updated accordingly.
Description
Semi-implicit source, described using an input dictionary. The injection
rate coefficients are specified as pairs of Su-Sp coefficients, i.e.
\f[
S(x) = S_u + S_p x
\f]
where
\vartable
S(x) | net source for field 'x'
S_u | explicit source contribution
S_p | linearised implicit contribution
\endvartable
Example tabulated heat source specification for internal energy:
\verbatim
volumeMode absolute; // specific
sources
{
e
{
explicit table ((0 0) (1.5 $power));
implicit 0;
}
}
\endverbatim
Example coded heat source specification for enthalpy:
\verbatim
volumeMode absolute; // specific
sources
{
h
{
explicit
{
type coded;
name heatInjection;
code
#{
// Power amplitude
const scalar powerAmplitude = 1000;
// x is the current time
return mag(powerAmplitude*sin(x));
#};
}
implicit 0;
}
}
\endverbatim
All of these sets will now take either "set" as the input entry, or
"cellSet"/"faceSet"/"pointSet" as appropriate. Previously cell and point
only accepted the "set" keyword whilst face only took "faceSet".
This is a topoSetSource which selects faces based on the adjacent cell
centres spanning a given plane. The plane is defined by a point and
normal vector.
Additionally, an include entry can be specified. When omitted or set to
"all", then all faces that meet the criteria are included in the set. When
set to "closest", just the faces that belong to the closest contiguous
region to the plane point are included. This latter setting is useful when
defining face zones through channels on which the flow rate is to be
computed, as it keeps the set local to a single channel.
An example usage (in system/topoSetDict) is as follows:
actions
(
{
name f0;
type faceZoneSet;
action new;
source planeToFaceZone;
sourceInfo
{
point (0 0 4);
normal (1 0 0.2);
include closest;
}
}
);
This would then allow the flow rate through the created face zone to be
accurately reported by the following command:
postProcess -func "flowRateFaceZone(name=f0,field=phi)"
The closeness option in surfaceFeatures set in surfaceFeaturesDict, e.g.
closeness
{
// Output the closeness of surface points to other surface elements.
pointCloseness yes;
}
calculates and writes both the internal and external surface "closeness"
measures either of which could be used to set the span refinement in
snappyHexMesh depending on which side of the surface is being meshed which is
specified with either refinement mode "insideSpan" or "externalSpan", e.g. in
the tutorials/mesh/snappyHexMesh/pipe case the inside of the pipe is meshed and
refined based on the internal span using the following specification:
refinementRegions
{
pipeWall
{
mode insideSpan;
levels ((1000 2));
cellsAcrossSpan 40;
}
}
Rather than specifying the controls per field it is simpler to use a single set
of controls for all the fields in the list and use separate instances of the
fieldAverage functionObject for different control sets:
Example of function object specification setting all the optional parameters:
fieldAverage1
{
type fieldAverage;
libs ("libfieldFunctionObjects.so");
writeControl writeTime;
restartOnRestart false;
restartOnOutput false;
periodicRestart false;
restartPeriod 0.002;
base time;
window 10.0;
windowName w1;
mean yes;
prime2Mean yes;
fields (U p);
}
This allows for a simple specification with the optional prime2Mean entry using
#includeFunc fieldAverage(U, p, prime2Mean = yes)
or if the prime2Mean is not needed just
#includeFunc fieldAverage(U, p)
Corrected the use of the lagged thermal phase change dmdt in interfacial
heat transfer calculations of n-phase simulations
Patch contributed by Juho Peltola, VTT.
To handle the additional optional specification for the closeness calculation
these settings are now is a sub-dictionary of surfaceFeaturesDict, e.g.
closeness
{
// Output the closeness of surface elements to other surface elements.
faceCloseness no;
// Output the closeness of surface points to other surface elements.
pointCloseness yes;
// Optional maximum angle between opposite points considered close
internalAngleTolerance 80;
externalAngleTolerance 80;
}
Description
PTT model for viscoelasticity using the upper-convected time
derivative of the stress tensor with support for multiple modes.
Reference:
\verbatim
Thien, N. P., & Tanner, R. I. (1977).
A new constitutive equation derived from network theory.
Journal of Non-Newtonian Fluid Mechanics, 2(4), 353-365.
\endverbatim
Currently the common exponential form of the PTT model is provided but it could
easily be extended to also support the linear and quadratic forms if the need
arises.
The \ continuation line marker is no longer required, multi-line argument lists
are parsed naturally by searching for the end ), e.g. in
tutorials/multiphase/reactingTwoPhaseEulerFoam/laminar/titaniaSynthesis/system/controlDict
#includeFunc writeObjects \
( \
d.particles, \
phaseTransfer:dmidtf.TiO2.particlesAndVapor \
)
is now written in the simpler form:
#includeFunc writeObjects
(
d.particles,
phaseTransfer:dmidtf.TiO2.particlesAndVapor
)
to support the more convenient #includeFunc specification in both
#includeFunc fieldAverage(U.air, U.water, alpha.air, p)
and
#includeFunc fieldAverage(fields = (U.air, U.water, alpha.air, p))
forms.
A single mode may now be specified either with the 'modes' list containing a
single entry:
// Example 1-mode specification
modes
(
{
lambda 0.01;
}
);
or by specifying the 'lambda' entry without 'modes'
// Single mode coefficient
lambda 0.03;
If both are provided the 'modes' entry will be used and a warning about the
unused 'lambda' entry printed.
By specifying a list of coefficients in turbulenceProperties, e.g. for the
generalised Maxwell model:
modes
(
{
lambda 0.01;
}
{
lambda 0.04;
}
);
of for the generalised Giesekus model:
modes
(
{
lambda 0.01;
alphaG 0.05;
}
{
lambda 0.04;
alphaG 0.2;
}
);
Visco-elasticity stress tensors (sigma0, sigma1...) are solved for each mode and
summed to create the effective stress of the complex fluid:
Any number of modes can be specified and if only one mode is required the
'modes' entry is not read and the coefficients are obtained as before.
The mode sigma? fields are read if present otherwise are constructed and
initialised from the sigma field but all of the mode sigma? fields are written
for restart and the sigma field contains the sum.
References:
http://en.wikipedia.org/wiki/Generalized_Maxwell_model
Wiechert, E. (1889). Ueber elastische Nachwirkung.
(Doctoral dissertation, Hartungsche buchdr.).
Wiechert, E. (1893).
Gesetze der elastischen Nachwirkung für constante Temperatur.
Annalen der Physik, 286(11), 546-570.
