STAR-CCM+#

Simcenter STAR-CCM+ is a commercial software tool for CFD and more generally computational continuum mechanics. As a general purpose CFD code Simcenter STAR-CCM+ provides a wide variety of physical models for turbulent flows, acoustics, Eulerian and Lagrangian multi-phase flow modeling, radiation, combustion and chemical reactions, heat and mass transfer including conjugate heat transfer in solid domains.

Licensing#

Please note that the clusters do not come with any license. If you want to use Simcenter STAR-CCM+ on the HPC clusters, you have to have access to suitable licenses. Several groups hold a joint license pool for non-commercial academic use which is coordinated through the software group of RRZE.

Availability / Target HPC systems#

Different versions of all Simcenter STAR-CCM+ are available via environment modules, which can be listed by module avail star-ccm+. A special version can be loaded, e.g. by module load star-ccm+/2310.

Production jobs should be run on the parallel HPC systems in batch mode.

Simcenter STAR-CCM+ can also be used in interactive GUI mode for serial pre- and/or post-processing on the login nodes. This should only be used to make quick simulation setup changes. It is not permitted to run computationally intensive Simcenter STAR-CCM+ simulation runs or serial/parallel post-processing sessions with large memory consumption on login nodes.

For pre- or post-processing of larger simulation cases via interactive GUI mode, have a look at our visualization node.

Notes#

Once you load the star-ccm+ module, the environment variable $PODKEY will hold your specific POD-key. The value will be updated centrally as needed. The POD-key from the HPC system will not work at your chair and vice versa.
We recommend writing automatic backup files (every 6 to 12 hours) for longer runs to be able to restart the simulation in case of a job or machine failure.
Star-CCM+ can be configured to stop after a certain elapsed simulation time. More information here
Besides the default mixed precision solver, Siemens PLM is also providing installation packages for higher accuracy double precision simulations. The latter comes for the price of approx. 20% higher execution times and approx. twice as large simulation results files. These modules are only available on demand and are named star-ccm+/XXX-r8.
Siemens PLM recently changed (with release 2020.x?) the default MPI used by STAR-CCM+ from HP/Platform MPI to Open MPI. Old job scripts may required changes to avoid errors due to incompatible MPI options. The sample scripts below have been updated accordingly.

Sample job scripts#

All job scripts have to contain the following information:

Resource definition for the queuing system (more details here)
Load Simcenter STAR-CCM+ environment module
Generate a file with names of hosts of the current simulation run to tell STAR-CCM+ on which nodes it should run (see example below)
Start command for parallel execution of starccm+ with all appropriate command line parameters, including a controlling STAR-CCM+ Java macro. Available parameters can be listed via starccm+ -help.

parallel STAR-CCM+ on Meggie#

The following script runs Star-CCM+ on Meggie in parallel on two nodes with 20 CPUs each.

#!/bin/bash -l
#SBATCH --job-name=my-ccm
#SBATCH --nodes=2
#SBATCH --ntasks-per-node=20
#SBATCH --time=24:00:00
#SBATCH --export=NONE

unset SLURM_EXPORT_ENV

# star-ccm+ arguments
CCMARGS="-load simxyz.sim"

# STAR-CCM+ version to use
module add star-ccm+/2310

# calculate the number of cores actually used
NUMCORES=$(( ${SLURM_JOB_NUM_NODES} * ${SLURM_NTASKS_PER_NODE} ))

# start STAR-CCM+
starccm+ -batch -cpubind v -np ${NUMCORES} --batchsystem slurm -power -podkey $PODKEY ${CCMARGS}

parallel STAR-CCM+ on Fritz#

The following script runs Star-CCM+ on Fritz in parallel on two nodes with 72 CPUs each.

#!/bin/bash -l
#SBATCH --job-name=my-ccm
#SBATCH --nodes=2
#SBATCH --ntasks-per-node=72
#SBATCH --time=24:00:00
#SBATCH --export=NONE

unset SLURM_EXPORT_ENV

# star-ccm+ arguments
CCMARGS="-load simxyz.sim"

# STAR-CCM+ version to use
module add star-ccm+/2310

# calculate the number of cores actually used
NUMCORES=$(( ${SLURM_JOB_NUM_NODES} * ${SLURM_NTASKS_PER_NODE} ))

# start STAR-CCM+
starccm+ -batch -cpubind v -np ${NUMCORES} --batchsystem slurm -power -podkey $PODKEY ${CCMARGS}