A collection of libraries and tools that let the user handle OpenFOAM-data based on expressions

Bernhard Gschaider (bgschaid@ice-sf.at)

Bernhard Gschaider (bgschaid@ice-sf.at)

None yet

See: http://openfoamwiki.net/index.php/contrib/swak4Foam

• Version 1.7 or 1.6-ext of OpenFOAM (1.6 should work, too)
  • The finiteArea-stuff will only work with version 1.6-ext
• the compiler generators bison and flex
• simpleSwakFunctionObjects needs the simpleFunctionObjects (see http://openfoamwiki.net/index.php/Contrib_simpleFunctionObjects) all other functionality has no additional requirements (simpleSwakFunctionObjects is only required by some examples) It is assumed that the sources are installed at $WM_PROJECT_USER_DIR/Libraries/simpleFunctionObjects

  A script downloadSimpleFunctionObjects.sh is provided that automatically downloads the simpleFunctionObjects into the Libraries-directory and compiles it. Warning: Don’t mix this with an installation at $WM_PROJECT_USER_DIR/Libraries/ unless you know what you’re doing

wmake all at the base directory should build all the libraries and tools.

The main library swak4FoamParsers can’t be built in parallel (no values of WM_NCOMPPROCS bigger than 1)

If the libraries and utilities are considered stable and the should be available to everyone (without having to recompile them) the script copySwakFilesToSite.sh can be used to copy them to the global site-specific directories.

The script removeSwakFilesFromSite.sh removes all these files from the global directories. The removeSwakFilesFromLocal.sh does the same for the user directories (this makes sure that no self-compiled version shadows the global version (which would lead to strange results)

There is a Makefile attached. make install compiles swak4Foam and installs it into the global directories

Note: Due to the order in which library direcories are searched for with -L a global installation might break the compilation

The command build dpkg builds a Debian/Ubuntu package for the currently enabled OpenFOAM-package. Note:

• it is assumed that the currently used OF-version was also installed by the package manager
• the dev package is built but poorly maintained
• simpleFunctionOjects are automatically included in the package. To avoid this remove the simpleFunctionObjects from the Libraries directory and do make dpkg-only

Changes in the packaging should be done in the branch debianPackaging of the Mercurial-repository

Note: Due to the problem described with the global installation it might be necessary to deinstall a previously installed package to successfully build a new package

Collection of Libraries

The basis of swak4Foam: the expression parsers with the logic to access the OpenFOAM data-structures.

None of the other software pieces compile without it

Implements the infamous groovyBC. A boundary condition that allows arbitrary expressions in the field-file

Function objects that have no additional requirements. Mainly used for manipulating and creating fields with expressions

Function objects based on the simpleFunctionObjects-library (which is a prerequisite for compiling it).

Evaluate expressions and output the results

These classes allow to manipulate the solution. To use these the solver has to be modified.

expressionSource

Field that is calculated from an expression. To be used as source-term or coefficient in some solver

forceEquation

force an equation to fixed values in selected locations. Has to be used after constructing the equation and before solving

topoSources for cellSet and faceSet. Can be used with the cellSet and faceSet-utilities

Implements parsers for the finiteArea-stuff in 1.6-ext. Also implements groovyBC for areaField and expressionField and other function objects

Collection of boundary conditions that give standard boundary conditions the possibility to use expression for the coefficients

Contributions to this library are explicitly encouraged. Please use the Mercurial-branch groovyStandardBCs to groovyify standard boundary conditions.

Utility that allows creation and manipulation of files with expressions

Utility like funkySetFields for areaFields (only works with 1.6-ext)

Sets any field on a boundary to a non-uniform value based on an expression.

Acts without deeper understanding of the underlying boundary condition

Utility to quickly test whether a groovyBC gives the expected results. Writes the specified fields with the applied boundary condition but doesn’t do anything else.

Can be used for other BCs as well

Evaluates expressions that are listed in a dictionary using data that is found on the disc and prints summarized data (min, max, average, sum) to the screen

If not otherwise noted cases are prepared by a simple blockMesh-call.

*All the cases here are strictly for demonstration purposes and resemble nothing from the ‘real world’*

The old groovyBC-Demos

Solver

pisoFoam

Also demonstrates

manipulateField, expressionField and clearField from the swakFunctionObjects. patchExpression from simpleSwakFunctionObjects.

Solver

solidDisplacementFoam

Solver

interDyMFoam

Remark

this one crashes halfway through the calculation. If you can fix it: Be my guest

Solver

pimpleDyMFoam

Also demonstrates

swakExpression with surface. Due to a problem described below this currently doesn’t work

Solver

pimpleFoam

Solver

chtMultiRegionFoam

Mesh preparation

Execute the script prepare.sh in that directory

Also demonstrated

patchExpression and swakExpression from simpleSwakFunctionObjects.

Solver

interFoam

Also demonstrates

Usage of a sampledSet defined in the controlDict do determine the average filling height. Also stored variables for not switching back once the criterion is reached. Global variables defined by a function object

Example dictionary for funkySetFields

Example dictionary for funkySetBoundaryFields. Sets nonsense boundary conditions for the world famous damBreak-case

Demonstrates usage of expressionSource

Due to differences in the original interFoam-solver this doesn’t work on certain OpenFOAM-versions (most specifically 1.6-ext).

The only modifications to the original solver are found at the end of createFields.H and in UEqn.H (the added source terms).

Demonstrates usage of forceEquation

Due to differences in the original interFoam-solver this doesn’t work on certain OpenFOAM-versions (most specifically 1.6-ext).

The only modifications to the original solver are found at the end of createFields.H and in UEqn.H (the fixing of the velocities).

Slightly modified version of interFoam. Adds a source term to the momentum equation. The source term is an expression that is defined at run-time

Demonstration case for it.

Preparation

Run the script prepare.sh to prepare the case

Demonstration of the finiteArea-stuff that works with 1.6-ext

Variation of surfactantFoam that adds an expressionSource

Demonstration case

Preparation

Use blockMesh and makeFaMesh

Solver

surfactantFoam (without source term) or swakSurfactantFoam

Demonstrates

FAM-specific swakExpressions and groovyBC (as well as the expressionSource)

Cases that don’t have a groovyBC

Solver

rhoPorousSimpleFoam

Mesh preparation

Execute the makeMesh.sh-script in that directory. If you want to run in parallel call the decomposeMesh.sh-script with the number of processors as an argument

Demonstrates

Usage of the swakTopoSources. Compares different approaches to evaluating with the swakExpression-functionObject. Also an example dictionary that demonstrates the use of funkyDoCalc

Solver

interFoam

Case preparation

run the supplied script prepareCase.sh

Demonstrates

Usage of a sampled surface to track the interface in a VOF-simulation

Simple test cases for specific features

Testing of different seeds for the rand-function. Also tests the randFixed-function

The preferred place for bug reports is http://sourceforge.net/apps/mantisbt/openfoam-extend/search.php?project_id=10&sticky_issues=on&sortby=last_updated&dir=DESC&hide_status_id=90

A sourceforge-account is required for reporting

Contributions to to swak4Foam are most welcome. If you want to contribute clone the Mercurial archive of the sources

hg clone http://openfoam-extend.hg.sourceforge.net:8000/hgroot/openfoam-extend/swak4Foam

Change to the branch that you want to improve (usually default) and create a new branch

hg branch <branchName>

where <branchname> is an easily identifiable name that makes the purpose of the branch clear (for instance bugfixWrongRandomFunction or featureHyperbolicFunctions). Don’t work on the default branch or any other branches that are not “yours”. Such contributions will not be merged

Once development on the branch is finished export the relevant changesets with

hg export <nodeID>

(nodeID being the ids of “your” changesets) and send them to the maintainer (or attach them to a bug report on Manits). The changes will be reviewed and merged into the default branch (do not attempt to do this yourself). Patches generated with hg export make sure that all changes are attributed to the original developer (you).

Once you have proven by successfully submitting changesets via hg export you can ask for write access to the mercurial repository.

These topics may be “new” for the average OF-developer:

Mercurial

A short tutorial on this can be found at http://mercurial.selenic.com/guide/. If you already know git the http://mercurial.selenic.com/wiki/GitConcepts may be enough for you

bison/flex

This pair of compiler generator tools generate the parsers for the expressions. Google for a tutorial that looks promising to you.

For a short example that shows how a new function was added to two parsers have a look at this changeset that added the cpu()-function to the field and the the patch-parser (usually you’ll have to write a new method for the driver too):

hg diff -c 8604e865cce6

Currently the main branches are:

default

The main branch. This is the brancht that the general public will receive. It compiles under 1.7 and 1.6-ext

port_2.0.x

The branch that compiles under OpenFOAM 2.0. This will eventually become the default-branch

debianPackaging

Branch for generating new Debian-packages of swak4Foam. If somebody wants to “inherit” this: contact the maintainer

finiteArea

In this branch the things for the finiteArea-discretization (only present in 1.6-ext) is developed. Usually gets merged back into the default-branch once a feature is completed

As an experimental feature distributed bug-tracking was introduced using the Artemis-extension for Mercurial (see http://hg.mrzv.org/Artemis/). An up-to-date version can be installed by

hg clone http://hg.mrzv.org/Artemis/

somewhere and installing the plugin by editing .hgrc.

This is not the official bug-tracker for swak4Foam. It is used for keeping track of new features that are to be introduced to swak4Foam and may be discontinued if the experiment proves to be unsuccessful.

swak4Foam is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. See the file COPYING in this directory, for a description of the GNU General Public License terms under which you can copy the files.

It seems that with moving meshes sampledSurfaces don’t get updated. This seems to be a problem with OpenFOAM itself (the regular surfaces-functionObject doesn’t get updated. This is currently investigated

Apart from patches and internal fields the support for interpolation from cells to faces (and vice versa) is incomplete as well as point fields (although they are supported in the grammar)

This is especially evident for the funkyDoCalc-example

Not really bugs, but stuff that bugs me

This is necessary because of bison. Investigate possibilities to replace these by tmp and autoPtr

valgrind reports some lost memory for stuff that is not directly allocated by swak4Foam (in OpenFOAM-sources)

Will investigate. Relevant places are marked by comments in the code. Also the construction of sampledSet seems to loose memory

First Release

New release Most important changes

Now expressions for the field on a sampled surface can be evaluated. All sampledSurfaces offered by OpenFOAM now can be used

The variables entry (most notably used in groovyBC and swakExpression) now can be a list of strings. This allows some kind of “formatting” (one expression per line) and should improve readability

These can copy the libraries and utilities to the global installation (for those who think that the swak4Foam-stuff is stable enough and want to ‘bless’ all users at their site with it). Note that any local installation still takes precedence (because $FOAM_USER_APPBIN is before $FOAM_APPBIN in the $PATH

This allows the inclusion of other parsers with the regular swak4Foam parsers and include them seamlessly with the variables-mechanism for ‘externals’ (in other words: you can add your own parser in a separate library without having to change anything about the overall swak4Foam, but it behaves as if it was part of it)

Now there is support for the finiteArea-library found in 1.6-dev. The support is found in a separate library swakFiniteArea. It has

• a parser faField for areaFields
• a parser faPatch for patches of areaFields
• a variant of groovyBC for these patches
• a computed source faExpressionSource
• Function-object-variants for areaFields: clearExpression, expressionField and manipulateField. These work the same as their volField-counterparts

See https://sourceforge.net/apps/mantisbt/openfoam-extend/view.php?id=49

See https://sourceforge.net/apps/mantisbt/openfoam-extend/view.php?id=44

New features and changes are (this list is not complete):

Like funkySetFields for finiteArea. Also writes out a volume field for easier post-processing

Makes it easier to use the groovyBC-machinery for other boundary conditions. Two standard boundary conditions were groovified. Others may follow

If no simpleFunctionObjects are present they can be downloaded by a script. Also scripts to handle global installations of swak4Foam

A class to force equations to certain values according to expressions

Utility does calculations on saved results and outputs single numbers (min, max, sum, average) to the terminal. Can be used for reporting or validity checks

Crude packaging for Debian

A single-argument function can be specified as a piecewise linear function. Basically works like timelines but the argument can be something else (not only the time)

Variables that store their values between time-steps. Applications are statistics or switches

Sampled sets can now also be used as en entity on which calculation is possible.

• These two functions now can receive an integer seed that determines the pseudo-randooom sequence generated by these functions
• Two functions randFixed and randNormalFixed were added. While the usual rand functions generate a different result at every time-steps for these functions the pseudo-random sequence is determined only by the seed (not by the timestep)

Take the bigger/smaller of two fields. Helps avoid ?:-operations

Application: If the results of the calculation are only needed in ParaView

• Use autoPtr for sets
• Update sets that change in memory or on disc

Fixed by Petr Vita

Calculated boundaries were $0$ and caused a division by zero

• Packaging information for the currently used OF-version is generated (allows a separate swak-package for every OF-version
• Submission to launchpad added

Now install to FOAM_SITE_APPBIN/LIBBIN

Uses the usual -region-option. Looks for a separate dictionary in the system-directory of that region

It is now possible to define variables that are ‘global’: They can be read in any entity.

Currently these variables can only be uniform.

To access global variables the specification-dictionary has to have a wordList named globalScopes. The scopes are searched in that order for the names of global variables. Having scopes allows some kind of separation of the variables