OpenFOAM
This is not a complete article: This is a draft, a work in progress that is intended to be published into an article, which may or may not be ready for inclusion in the main wiki. It should not necessarily be considered factual or authoritative.
The OpenFOAM (Open Field Operation and Manipulation) CFD Toolbox is a free, open source software package for computational fluid dynamics. OpenFOAM has an extensive range of features to solve anything from complex fluid flows involving chemical reactions, turbulence and heat transfer, to solid dynamics and electromagnetics.
Modulefiles
module load openfoam will give you a recent version.
The OpenFOAM development community is divided into two parts:
- The OpenFOAM Foundation Ltd., with web sites openfoam.org and cfd.direct
- OpenCFD Ltd., with web site openfoam.com
Up to version 2.3.1, released in December 2014, the release histories appear to be the same. Compute Canada module names after 2.3.1 which begin with "v" are derived from the .com branch; those beginning with a digit are derived from the .org branch (for example, openfoam/v1712).
See Using modules for more on module commands.
Documentation
OpenFOAM.com documentation and CFD Direct user guide.
Usage
OpenFOAM requires substantial preparation of your environment. In order to run OpenFOAM commands (such as paraFoam, blockMesh, etc), you must load a modulefile followed by sourcing a configuration script.
Here is an example of a serial submission script for OpenFOAM 5.0:
#!/bin/bash #SBATCH --time=00:01:00 #SBATCH --account=def-someuser module purge module load openfoam/5.0 source $FOAM_ETC/bashrc blockMesh icoFoam
Here is an example of a parallel submission script:
#!/bin/bash
#SBATCH --account=def-someuser
#SBATCH --ntasks=4 # number of MPI processes
#SBATCH --mem-per-cpu=1024M # memory; default unit is megabytes
#SBATCH --time=0-00:10 # time (DD-HH:MM)
module purge
module load openfoam/5.0
source $FOAM_ETC/bashrc
decomposePar
blockMesh
setFields
srun interFoam -parallel
Mesh preparation (blockMesh) may be fast enough to be done at the command line (see Running jobs). The solver (icoFoam and others) is usually the most expensive step and should always be submitted as a Slurm job except in very small test cases or tutorials.
Performance
OpenFOAM can emit a lot of debugging information in very frequent small writes (e.g. hundreds per second). This may lead to poor performance on our network file systems. If you are in stable production and don't need the debug output, you can reduce or disable it with:
$ mkdir -p $HOME/.OpenFOAM/$WM_PROJECT_VERSION $ cp $WM_PROJECT_DIR/etc/controlDict $HOME/.OpenFOAM/$WM_PROJECT_VERSION/
Then edit the debugSwitches dictionary in $HOME/.OpenFOAM/$WM_PROJECT_VERSION/controlDict, changing flags from values >0 to 0. (Contribution from C. Lane)