For example in the potentialFreeSurfaceFoam/oscillatingBox tutorial it is
cleaner to apply the "linearRamp" function to the "sine" function rather than
using an amplitude table:
floatingObject
{
type fixedNormalInletOutletVelocity;
fixTangentialInflow false;
normalVelocity
{
type uniformFixedValue;
uniformValue
{
type scale;
value
{
type sine;
frequency 1;
amplitude 0.025;
scale (0 1 0);
level (0 0 0);
}
scale
{
type linearRamp;
duration 10;
}
}
}
value uniform (0 0 0);
}
including support for TDAC and ISAT for efficient chemistry calculation.
Description
Eddy Dissipation Concept (EDC) turbulent combustion model.
This model considers that the reaction occurs in the regions of the flow
where the dissipation of turbulence kinetic energy takes place (fine
structures). The mass fraction of the fine structures and the mean residence
time are provided by an energy cascade model.
There are many versions and developments of the EDC model, 4 of which are
currently supported in this implementation: v1981, v1996, v2005 and
v2016. The model variant is selected using the optional \c version entry in
the \c EDCCoeffs dictionary, \eg
\verbatim
EDCCoeffs
{
version v2016;
}
\endverbatim
The default version is \c v2015 if the \c version entry is not specified.
Model versions and references:
\verbatim
Version v2005:
Cgamma = 2.1377
Ctau = 0.4083
kappa = gammaL^exp1 / (1 - gammaL^exp2),
where exp1 = 2, and exp2 = 2.
Magnussen, B. F. (2005, June).
The Eddy Dissipation Concept -
A Bridge Between Science and Technology.
In ECCOMAS thematic conference on computational combustion
(pp. 21-24).
Version v1981:
Changes coefficients exp1 = 3 and exp2 = 3
Magnussen, B. (1981, January).
On the structure of turbulence and a generalized
eddy dissipation concept for chemical reaction in turbulent flow.
In 19th Aerospace Sciences Meeting (p. 42).
Version v1996:
Changes coefficients exp1 = 2 and exp2 = 3
Gran, I. R., & Magnussen, B. F. (1996).
A numerical study of a bluff-body stabilized diffusion flame.
Part 2. Influence of combustion modeling and finite-rate chemistry.
Combustion Science and Technology, 119(1-6), 191-217.
Version v2016:
Use local constants computed from the turbulent Da and Re numbers.
Parente, A., Malik, M. R., Contino, F., Cuoci, A., & Dally, B. B.
(2016).
Extension of the Eddy Dissipation Concept for
turbulence/chemistry interactions to MILD combustion.
Fuel, 163, 98-111.
\endverbatim
Tutorials cases provided: reactingFoam/RAS/DLR_A_LTS, reactingFoam/RAS/SandiaD_LTS.
This codes was developed and contributed by
Zhiyi Li
Alessandro Parente
Francesco Contino
from BURN Research Group
and updated and tested for release by
Henry G. Weller
CFD Direct Ltd.
to provide smoother behavior on start-up when an acceleration impulse is
applied, e.g. if the body is suddenly released. e.g.
dynamicFvMesh dynamicMotionSolverFvMesh;
motionSolverLibs ("librigidBodyMeshMotion.so");
solver rigidBodyMotion;
rigidBodyMotionCoeffs
{
report on;
solver
{
type Newmark;
}
ramp
{
type quadratic;
start 0;
duration 10;
}
.
.
.
will quadratically ramp the forces from 0 to their full values over the first
10s of the run starting from 0. If the 'ramp' entry is omitted no force ramping
is applied.
Description
Ramp function base class for the set of scalar functions starting from 0 and
increasing monotonically to 1 from \c start over the \c duration and
remaining at 1 thereafter.
Usage:
\verbatim
<entryName> <rampFunction>;
<entryName>Coeffs
{
start 10;
duration 20;
}
\endverbatim
or
\verbatim
<entryName>
{
type <rampFunction>;
start 10;
duration 20;
}
\endverbatim
Where:
\table
Property | Description | Required | Default value
start | Start time | no | 0
duration | Duration | yes |
\endtable
The following common ramp functions are provided: linear, quadratic, halfCosine,
quarterCosine and quaterSine, others can easily be added and registered to the run-time
selection system.
e.g.
ramp
{
type quadratic;
start 200;
duration 1.6;
}
but the old format is supported for backward compatibility:
ramp linear;
rampCoeffs
{
start 200;
duration 1.6;
}
Formally this is equivalent to the previous formulation but more convenient to
use given that for compressible flow the mass flux rather than the volume flux
is available.
These legacy boundary conditions are no longer needed and have been superseded
by the more flexible sixDoFRigidBodyMotion and rigidBodyMotion solvers. See tutorials:
incompressible/pimpleDyMFoam/wingMotion/wingMotion2D_pimpleDyMFoam
multiphase/interDyMFoam/RAS/DTCHull
multiphase/interDyMFoam/RAS/floatingObject
Resolves bug-report https://bugs.openfoam.org/view.php?id=2487
Using
decomposePar -copyZero
The mesh is decomposed as usual but the '0' directory is recursively copied to
the 'processor.*' directories rather than decomposing the fields. This is a
convenient option to handle cases where the initial field files are generic and
can be used for serial or parallel running. See for example the
incompressible/simpleFoam/motorBike tutorial case.
Both stardard SIMPLE and the SIMPLEC (using the 'consistent' option in
fvSolution) are now supported for both subsonic and transonic flow of all
fluid types.
rhoPimpleFoam now instantiates the lower-level fluidThermo which instantiates
either a psiThermo or rhoThermo according to the 'type' specification in
thermophysicalProperties, see also commit a1c8cde310
Both stardard SIMPLE and the SIMPLEC (using the 'consistent' option in
fvSolution) are now supported for both subsonic and transonic flow of all
fluid types.
rhoSimpleFoam now instantiates the lower-level fluidThermo which instantiates
either a psiThermo or rhoThermo according to the 'type' specification in
thermophysicalProperties, e.g.
thermoType
{
type hePsiThermo;
mixture pureMixture;
transport sutherland;
thermo janaf;
equationOfState perfectGas;
specie specie;
energy sensibleInternalEnergy;
}
instantiates a psiThermo for a perfect gas with JANAF thermodynamics, whereas
thermoType
{
type heRhoThermo;
mixture pureMixture;
properties liquid;
energy sensibleInternalEnergy;
}
mixture
{
H2O;
}
instantiates a rhoThermo for water, see new tutorial
compressible/rhoSimpleFoam/squareBendLiq.
In order to support complex equations of state the pressure can no longer be
unlimited and rhoSimpleFoam now limits the pressure rather than the density to
handle start-up more robustly.
For backward compatibility 'rhoMin' and 'rhoMax' can still be used in the SIMPLE
sub-dictionary of fvSolution which are converted into 'pMax' and 'pMin' but it
is better to set either 'pMax' and 'pMin' directly or use the more convenient
'pMinFactor' and 'pMinFactor' from which 'pMax' and 'pMin' are calculated using
the fixed boundary pressure or reference pressure e.g.
SIMPLE
{
nNonOrthogonalCorrectors 0;
pMinFactor 0.1;
pMaxFactor 1.5;
transonic yes;
consistent yes;
residualControl
{
p 1e-3;
U 1e-4;
e 1e-3;
"(k|epsilon|omega)" 1e-3;
}
}
