Registration occurs when the temporary field is transferred to a non-temporary
field via a constructor or if explicitly transferred to the database via the
regIOobject "store" methods.
This object calculates a field of the age of fluid in the domain; i.e.,
the time taken for a fluid particle to travel to a location from an
inlet. It outputs a field, named age, with dimensions of time, and
requires a solver and a div(phi,age) scheme to be specified. A number of
corrections for the solution procedure can be set, as well as the name
of the flux and density fields.
Example specification:
age1
{
type age;
libs ("libfieldFunctionObjects.so");
nCorr 10;
phi phi;
rho rho;
}
Example usage:
postProcess -func age -fields "(phi)" -latestTime
This work was supported by Robert Secor and Lori Holmes, at 3M
Now for transient simulations "Final" solver settings are required for ALL
equations providing consistency between the solution of velocity, energy,
composition and radiation properties.
However "Final" relaxation factors are no longer required for fields or
equations and if not present the standard value for the variable will be
applied. Given that relaxation factors other than 1 are rarely required for
transient runs and hence the same for all iterations including the final one
this approach provide simpler input while still providing the flexibility to
specify a different value for the final iteration if required. For steady cases
it is usual to execute just 1 outer iteration per time-step for which the
standard relaxation factors are appropriate, and if more than one iteration is
executed it is common to use the same factors for both. In the unlikely event
of requiring different relaxation factors for the final iteration this is still
possible to specify via the now optional "Final" specification.
By default the prefix is no longer added to the field names but the previous
behaviour can be reproduced by setting the optional "prefix" entry to "on" or
"yes".
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$x\f$.
The etc/caseDicts/postProcessing/fields/log configuration file is provided so
that the simple #includeFunc can be used to execute this functionObject during
the run, e.g. for some dimensionless field x
functions
{
#includeFunc log(x)
}
or if x might be 0 or negative in some regions the optional clip may be applied:
functions
{
#includeFunc log(p,clip=1e-6)
}
The projection direction has been corrected to include the effect of
mesh motion. The case where the source and receiving faces are of
differing orientations and the particle displacement points into both is
now detected and handled.
The sampled sets have been renamed in a more explicit and consistent
manner, and two new ones have also been added. The available sets are as
follows:
arcUniform: Uniform samples along an arc. Replaces "circle", and
adds the ability to sample along only a part of the circle's
circumference. Example:
{
type arcUniform;
centre (0.95 0 0.25);
normal (1 0 0);
radial (0 0 0.25);
startAngle -1.57079633;
endAngle 0.52359878;
nPoints 200;
axis x;
}
boundaryPoints: Specified point samples associated with a subset of
the boundary. Replaces "patchCloud". Example:
{
type boundaryPoints;
patches (inlet1 inlet2);
points ((0 -0.05 0.05) (0 -0.05 0.1) (0 -0.05 0.15));
maxDistance 0.01;
axis x;
}
boundaryRandom: Random samples within a subset of the boundary.
Replaces "patchSeed", but changes the behaviour to be entirely
random. It does not seed the boundary face centres first. Example:
{
type boundaryRandom;
patches (inlet1 inlet2);
nPoints 1000;
axis x;
}
boxUniform: Uniform grid of samples within a axis-aligned box.
Replaces "array". Example:
{
type boxUniform;
box (0.95 0 0.25) (1.2 0.25 0.5);
nPoints (2 4 6);
axis x;
}
circleRandom: Random samples within a circle. New. Example:
{
type circleRandom;
centre (0.95 0 0.25);
normal (1 0 0);
radius 0.25;
nPoints 200;
axis x;
}
lineFace: Face-intersections along a line. Replaces "face". Example:
{
type lineFace;
start (0.6 0.6 0.5);
end (0.6 -0.3 -0.1);
axis x;
}
lineCell: Cell-samples along a line at the mid-points in-between
face-intersections. Replaces "midPoint". Example:
{
type lineCell;
start (0.5 0.6 0.5);
end (0.5 -0.3 -0.1);
axis x;
}
lineCellFace: Combination of "lineFace" and "lineCell". Replaces
"midPointAndFace". Example:
{
type lineCellFace;
start (0.55 0.6 0.5);
end (0.55 -0.3 -0.1);
axis x;
}
lineUniform: Uniform samples along a line. Replaces "uniform".
Example:
{
type lineUniform;
start (0.65 0.3 0.3);
end (0.65 -0.3 -0.1);
nPoints 200;
axis x;
}
points: Specified points. Replaces "cloud" when the ordered flag is
false, and "polyLine" when the ordered flag is true. Example:
{
type points;
points ((0 -0.05 0.05) (0 -0.05 0.1) (0 -0.05 0.15));
ordered yes;
axis x;
}
sphereRandom: Random samples within a sphere. New. Example:
{
type sphereRandom;
centre (0.95 0 0.25);
radius 0.25;
nPoints 200;
axis x;
}
triSurfaceMesh: Samples from all the points of a triSurfaceMesh.
Replaces "triSurfaceMeshPointSet". Example:
{
type triSurfaceMesh;
surface "surface.stl";
axis x;
}
The headers have also had documentation added. Example usage and a
description of the control parameters now exists for all sets.
In addition, a number of the algorithms which generate the sets have
been refactored or rewritten. This was done either to take advantage of
the recent changes to random number generation, or to remove ad-hoc
fixes that were made unnecessary by the barycentric tracking algorithm.
This is faster than the library functionality that it replaces, as it
allows the compiler to do inlining. It also does not utilise any static
state so generators do not interfere with each other. It is also faster
than the the array lookup in cachedRandom. The cachedRandom class
therefore offers no advantage over Random and has been removed.
Streamlines can now be tracked in both directions from the set of
initial locations. The keyword controlling this behaviour is
"direction", which can be set to "forward", "backward" or "both".
This new keyword superseeds the "trackForward" entry, which has been
retained for backwards compatibility.
It may be convenient to specify these directions un-normalized so it is
necessary to normalize them before they are used to calculate the force
coefficients.
Description
Evaluates and writes the turbulence intensity field 'I'.
The turbulence intensity field 'I' is the root-mean-square of the turbulent
velocity fluctuations normalised by the local velocity magnitude:
\f[
I \equiv \frac{\sqrt{\frac{2}{3}\, k}}{U}
\f]
To avoid spurious extrema and division by 0 I is limited to 1 where the
velocity magnitude is less than the turbulent velocity fluctuations.
Example of function object specification:
\verbatim
functions
{
.
.
.
turbulenceIntensity
{
type turbulenceIntensity;
libs ("libfieldFunctionObjects.so");
}
.
.
.
}
\endverbatim
or using the standard configuration file:
\verbatim
functions
{
.
.
.
#includeFunc turbulenceIntensity
.
.
.
}
\endverbatim
The logic governing function objects' ability to change the time-step
has been modified so that it is compatible with the time-step adjustment
done in the Time class. The behaviour has been split into a method which
sets the step directly, and another which moidifies the time until the
next write operation (i.e., the time that the solver "aims" for).
This fixes an issue where the adjustments in Time and the function
objects interfere and cause the time step to decrease exponentially down
to machine precision. It also means that the set-time-step function
object now does not break the adjustable run-time setting.
This resolves bug report https://bugs.openfoam.org/view.php?id=2820
In early versions of OpenFOAM the scalar limits were simple macro replacements and the
names were capitalized to indicate this. The scalar limits are now static
constants which is a huge improvement on the use of macros and for consistency
the names have been changed to camel-case to indicate this and improve
readability of the code:
GREAT -> great
ROOTGREAT -> rootGreat
VGREAT -> vGreat
ROOTVGREAT -> rootVGreat
SMALL -> small
ROOTSMALL -> rootSmall
VSMALL -> vSmall
ROOTVSMALL -> rootVSmall
The original capitalized are still currently supported but their use is
deprecated.
and optionally the CPU and clock times per time step.
Example of function object specification:
time
{
type time;
libs ("libutilityFunctionObjects.so");
writeControl timeStep;
writeInterval 1;
perTimeStep no;
}
Adding
#includeFunc time
to the functions list in the controlDict of the motorBike tutorial generates
0 1.190000e+00 1
1 1.640000e+00 1
2 1.940000e+00 2
Enabling the optional writing of the CPU and clock time per time step is
straight forward:
#includeFunc time(perTimeStep=yes)
for incompressible flow simulated using simpleFoam, pimpleFoam or pisoFoam.
Description
Calculates and write the estimated incompressible flow heat transfer
coefficient at wall patches as the volScalarField field
'wallHeatTransferCoeff'.
All wall patches are included by default; to restrict the calculation to
certain patches, use the optional 'patches' entry.
Example of function object specification:
wallHeatTransferCoeff1
{
type wallHeatTransferCoeff;
libs ("libfieldFunctionObjects.so");
...
region fluid;
patches (".*Wall");
rho 1.225;
Cp 1005;
Prl 0.707;
Prt 0.9;
}
Usage
Property | Description | Required | Default value
type | Type name: wallHeatTransferCoeff | yes |
patches | List of patches to process | no | all wall patches
region | Region to be evaluated | no | default region
rho | Fluid density | yes |
Cp | Fluid heat capacity | yes |
Prl | Fluid laminar Prandtl number | yes |
Prt | Fluid turbulent Prandtl number| yes |
Note
Writing field 'wallHeatTransferCoeff' is done by default, but it can be
overridden by defining an empty \c objects list. For details see
writeLocalObjects.
Corrected a few issues with the utilisation of the tracking within the
nearWallFields function object. The tracking is now done over a
displacement from the initial location, which prevents trying to track
to a location outside the mesh when the patch face is warped and the
centre lies outside the tracking decomposition. Also fixed the end
criteria so that it does not suffer from round off error in the step
fraction.
The upshot of these changes is that the faces on which the near wall
cells were not being set are now being set properly, and uninitialised
data is no longer being written out.
Removed all the special handling for awkward particles from the
nearWallFields function object. The version 5+ tracking already handles
this more robustly.
Resolves bug-report https://bugs.openfoam.org/view.php?id=2728
