This is a packaged function object that conveniently computes averages
of fields on tri-surfaces. It can be executed on the command line as
follows:
foamPostProcess -func "triSurfaceAverage(name=mid.obj, p)"
This will compute the average of the field "p" on a surface file in
"constant/geometry/mid.obj".
The calculation could also be done at run-time by adding the following
entry to the functions section of the system/controlDict
#includeFunc triSurfaceAverage(name=mid.obj, p)
Packaged function objects can now be deployed equally effectively by
(a) using a locally edited copy of the configuration file, or by
(b) passing parameters as arguments to the global configuration file.
For example, to post-process the pressure field "p" at a single location
"(1 2 3)", the user could first copy the "probes" packaged function
object file to their system directory by calling "foamGet probes". They
could then edit the file to contain the following entries:
points ((1 2 3));
field p;
The function object can then be executed by the postProcess application:
postProcess -func probes
Or it can be called at run-time, by including from within the functions
section of the system/controlDict file:
#includeFunc probes
Alternatively, the field and points parameters could be passed as
arguments either to the postProcess application by calling:
postProcess -func "probes(points=((1 2 3)), p)"
Or by using the #includeFunc directive:
#includeFunc probes(points=((1 2 3)), p)
In both cases, mandatory parameters that must be either edited or
provided as arguments are denoted in the configuration files with
angle-brackets, e.g.:
points (<points>);
Many of the packaged function objects have been split up to make them
more specific to a particular use-case. For example, the "surfaces"
function has been split up into separate functions for each surface
type; "cutPlaneSurface", "isoSurface", and "patchSurface". This
splitting means that the packaged functions now only contain one set of
relevant parameters so, unlike previously, they now work effectively
with their parameters passed as arguments. To ensure correct usage, all
case-dependent parameters are considered mandatory.
For example, the "streamlines" packaged function object has been split
into specific versions; "streamlinesSphere", "streamlinesLine",
"streamlinesPatch" and "streamlinesPoints". The name ending denotes the
seeding method. So, the following command creates ten streamlines with
starting points randomly seeded within a sphere with a specified centre
and radius:
postProcess -func "streamlinesSphere(nPoints=10, centre=(0 0 0), radius=1)"
The equivalent #includeFunc approach would be:
#includeFunc streamlinesSphere(nPoints=10, centre=(0 0 0), radius=1)
When passing parameters as arguments, error messages report accurately
which mandatory parameters are missing and provide instructions to
correct the format of the input. For example, if "postProcess -func
graphUniform" is called, then the code prints the following error message:
--> FOAM FATAL IO ERROR:
Essential value for keyword 'start' not set
Essential value for keyword 'end' not set
Essential value for keyword 'nPoints' not set
Essential value for keyword 'fields' not set
In function entry:
graphUniform
In command:
postProcess -func graphUniform
The function entry should be:
graphUniform(start = <point>, end = <point>, nPoints = <number>, fields = (<fieldNames>))
file: controlDict/functions/graphUniform from line 15 to line 25.
As always, a full list of all packaged function objects can be obtained
by running "postProcess -list", and a description of each function can
be obtained by calling "foamInfo <functionName>". An example case has
been added at "test/postProcessing/channel" which executes almost all
packaged function objects using both postProcess and #includeFunc. This
serves both as an example of syntax and as a unit test for maintenance.
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.
This change formalises the usage of the "log" keyword in function
objects. By default, logging to stdout is activated when running
"postProcess" or "<solver> -postProcess", and deactivated when a
function is being executed as part of a run.
This behaviour can now be overridden in the function object dictionary
when operating in either mode.
e.g. given a vol pressure field p
functions
{
// Interpolate the pressure field to the faces
surfacep
{
type surfaceInterpolate;
libs ("libfieldFunctionObjects.so");
fields ((p surfacep));
writeControl none;
}
// Average the surface pressure field over the centre faceZone
#includeFunc faceZoneAverage(name=centre, surfacep)
.
.
.
}
Both the functionObject call context (the command line for postProcess, and the
controlDict path for run-time post-precessing) and the configuration file
context where the arguments are substituted are now printed in the error
message, e.g.
postProcess -func 'patchAverage(name=inlet, ields=(p U))'
generates the message
--> FOAM FATAL IO ERROR:
Essential value for keyword 'fields' not set in function entry
patchAverage(name=inlet, ields=(p U))
in command line postProcess -func patchAverage(name=inlet, ields=(p U))
Placeholder value is <field_names>
file: /home/dm2/henry/OpenFOAM/OpenFOAM-dev/etc/caseDicts/postProcessing/surfaceFieldValue/patchAverage from line 13 to line 17.
and with the following in controlDict
functions
{
#includeFunc patchAverage(name=inlet, ields=(p U))
}
generates the message
--> FOAM FATAL IO ERROR:
Essential value for keyword 'fields' not set in function entry
patchAverage(name=inlet, ields=(p U))
in file /home/dm2/henry/OpenFOAM/OpenFOAM-dev/tutorials/incompressible/pimpleFoam/RAS/pitzDaily/system/controlDict at line 55
Placeholder value is <field_names>
file: /home/dm2/henry/OpenFOAM/OpenFOAM-dev/etc/caseDicts/postProcessing/surfaceFieldValue/patchAverage from line 13 to line 17.
to rationalise the structure and class names to avoid the need for the confusing
addNamedToRunTimeSelectionTable and use instead use the standard
addToRunTimeSelectionTable to populate the run-time selection table.
