openfoam/tutorials/discreteMethods/dsmcFoam
Henry Weller e4dc50dcb0 postProcessing: Replaced 'foamCalc' and the 'postCalc' utilities
with the more general and flexible 'postProcess' utility and '-postProcess' solver option

Rationale
---------

Both the 'postProcess' utility and '-postProcess' solver option use the
same extensive set of functionObjects available for data-processing
during the run avoiding the substantial code duplication necessary for
the 'foamCalc' and 'postCalc' utilities and simplifying maintenance.
Additionally consistency is guaranteed between solver data processing
and post-processing.

The functionObjects have been substantially re-written and generalized
to simplify development and encourage contribution.

Configuration
-------------

An extensive set of simple functionObject configuration files are
provided in

OpenFOAM-dev/etc/caseDicts/postProcessing

and more will be added in the future.  These can either be copied into
'<case>/system' directory and included into the 'controlDict.functions'
sub-dictionary or included directly from 'etc/caseDicts/postProcessing'
using the '#includeEtc' directive or the new and more convenient
'#includeFunc' directive which searches the
'<etc>/caseDicts/postProcessing' directories for the selected
functionObject, e.g.

functions
{
    #includeFunc Q
    #includeFunc Lambda2
}

'#includeFunc' first searches the '<case>/system' directory in case
there is a local configuration.

Description of #includeFunc
---------------------------

    Specify a functionObject dictionary file to include, expects the
    functionObject name to follow (without quotes).

    Search for functionObject dictionary file in
    user/group/shipped directories.
    The search scheme allows for version-specific and
    version-independent files using the following hierarchy:
    - \b user settings:
      - ~/.OpenFOAM/\<VERSION\>/caseDicts/postProcessing
      - ~/.OpenFOAM/caseDicts/postProcessing
    - \b group (site) settings (when $WM_PROJECT_SITE is set):
      - $WM_PROJECT_SITE/\<VERSION\>/caseDicts/postProcessing
      - $WM_PROJECT_SITE/caseDicts/postProcessing
    - \b group (site) settings (when $WM_PROJECT_SITE is not set):
      - $WM_PROJECT_INST_DIR/site/\<VERSION\>/caseDicts/postProcessing
      - $WM_PROJECT_INST_DIR/site/caseDicts/postProcessing
    - \b other (shipped) settings:
      - $WM_PROJECT_DIR/etc/caseDicts/postProcessing

    An example of the \c \#includeFunc directive:
    \verbatim
        #includeFunc <funcName>
    \endverbatim

postProcess
-----------

The 'postProcess' utility and '-postProcess' solver option provide the
same set of controls to execute functionObjects after the run either by
reading a specified set of fields to process in the case of
'postProcess' or by reading all fields and models required to start the
run in the case of '-postProcess' for each selected time:

postProcess -help

Usage: postProcess [OPTIONS]
options:
  -case <dir>       specify alternate case directory, default is the cwd
  -constant         include the 'constant/' dir in the times list
  -dict <file>      read control dictionary from specified location
  -field <name>     specify the name of the field to be processed, e.g. U
  -fields <list>    specify a list of fields to be processed, e.g. '(U T p)' -
                    regular expressions not currently supported
  -func <name>      specify the name of the functionObject to execute, e.g. Q
  -funcs <list>     specify the names of the functionObjects to execute, e.g.
                    '(Q div(U))'
  -latestTime       select the latest time
  -newTimes         select the new times
  -noFunctionObjects
                    do not execute functionObjects
  -noZero           exclude the '0/' dir from the times list, has precedence
                    over the -withZero option
  -parallel         run in parallel
  -region <name>    specify alternative mesh region
  -roots <(dir1 .. dirN)>
                    slave root directories for distributed running
  -time <ranges>    comma-separated time ranges - eg, ':10,20,40:70,1000:'
  -srcDoc           display source code in browser
  -doc              display application documentation in browser
  -help             print the usage

 pimpleFoam -postProcess -help

Usage: pimpleFoam [OPTIONS]
options:
  -case <dir>       specify alternate case directory, default is the cwd
  -constant         include the 'constant/' dir in the times list
  -dict <file>      read control dictionary from specified location
  -field <name>     specify the name of the field to be processed, e.g. U
  -fields <list>    specify a list of fields to be processed, e.g. '(U T p)' -
                    regular expressions not currently supported
  -func <name>      specify the name of the functionObject to execute, e.g. Q
  -funcs <list>     specify the names of the functionObjects to execute, e.g.
                    '(Q div(U))'
  -latestTime       select the latest time
  -newTimes         select the new times
  -noFunctionObjects
                    do not execute functionObjects
  -noZero           exclude the '0/' dir from the times list, has precedence
                    over the -withZero option
  -parallel         run in parallel
  -postProcess      Execute functionObjects only
  -region <name>    specify alternative mesh region
  -roots <(dir1 .. dirN)>
                    slave root directories for distributed running
  -time <ranges>    comma-separated time ranges - eg, ':10,20,40:70,1000:'
  -srcDoc           display source code in browser
  -doc              display application documentation in browser
  -help             print the usage

The functionObjects to execute may be specified on the command-line
using the '-func' option for a single functionObject or '-funcs' for a
list, e.g.

postProcess -func Q
postProcess -funcs '(div(U) div(phi))'

In the case of 'Q' the default field to process is 'U' which is
specified in and read from the configuration file but this may be
overridden thus:

postProcess -func 'Q(Ua)'

as is done in the example above to calculate the two forms of the divergence of
the velocity field.  Additional fields which the functionObjects may depend on
can be specified using the '-field' or '-fields' options.

The 'postProcess' utility can only be used to execute functionObjects which
process fields present in the time directories.  However, functionObjects which
depend on fields obtained from models, e.g. properties derived from turbulence
models can be executed using the '-postProcess' of the appropriate solver, e.g.

pisoFoam -postProcess -func PecletNo

or

sonicFoam -postProcess -func MachNo

In this case all required fields will have already been read so the '-field' or
'-fields' options are not be needed.

Henry G. Weller
CFD Direct Ltd.
2016-05-28 18:58:48 +01:00
..
freeSpacePeriodic postProcessing: Replaced 'foamCalc' and the 'postCalc' utilities 2016-05-28 18:58:48 +01:00
freeSpaceStream postProcessing: Replaced 'foamCalc' and the 'postCalc' utilities 2016-05-28 18:58:48 +01:00
supersonicCorner postProcessing: Replaced 'foamCalc' and the 'postCalc' utilities 2016-05-28 18:58:48 +01:00
wedge15Ma5 postProcessing: Replaced 'foamCalc' and the 'postCalc' utilities 2016-05-28 18:58:48 +01:00
README STYLE: README for dsmcFoam cases explaining the fields. 2011-03-24 15:52:00 +00:00

Fields are used by dsmcFoam in several ways, some of which are different to
their use elsewhere in OpenFOAM.  None of these fields are solved by partial
differential equations, they are used either to record simulation data, or to
supply boundary data.

In each case there are 11 fields:

    boundaryT, boundaryU:

        The wall and free stream conditions at the boundary are specified for
        velocity and temperature with these fields - only the data on the
        patches is used, the cell data is not.  These are the only two fields
        which supply data to the case.

    dsmcRhoN:

        The population of dsmc particles in cells is recorded to visualise how
        well the cell population conditions required for dsmc are met.  The
        boundary conditions are zeroGradient because only cell data is
        meaningful.

    fD, q:

        The wall heat flux (q) and force density (fD, i.e. stress vector) is
        recorded with these fields - only the data on wall patches is relevant,
        the cell data is not.

    iDof, internalE, linearKE, momentum, rhoM, rhoN:

        These fields are the densities of extensive quantities in the
        simulation, i.e. of number, mass, momentum, energy.  Cell data is
        recorded in the internal field and the boundaryField is used to record
        the data of particles that strike wall patches.  The properties of
        particles striking wall faces are weighted by 1/(Un*fA), where Un is the
        normal component of the particle's velocity and fA is the face area.
        This is done so that when intensive quantities, such as velocity or
        temperature, are evaluated on the wall the values are correct this
        allows velocity slip and temperature jump to be evaluated.

        Therefore, the data in these fields on wall patches is of a different
        type to the volume data.  This may cause problems when post-processing,
        as any interpolation of these fields will have a artifacts in the near
        wall cells because the values on the faces are radically different.
        This can be overcome by visualising the data uninterpolated, or by
        copying the fields and setting zeroGradient boundary conditions on
        walls.  Calculated intensive fields do not have this issue.

Further fields are produced by dsmcFoam, i.e. dsmcSigmaTcRMax (used in the
selection of collision partners) and by the fieldAverage (averaging the
extensive quantity densities) and dsmcFields (calculating intensive quantities,
i.e. velocity and temperature, from extensive quantities) function objects in
each case as it runs.