COMSOL Multiphysics® is a simulation platform for modeling and computing multiphysics problems based on partial differential equations in 1D, 2D, and 3D. It enables the analysis of coupled physical phenomena across a wide range of disciplines, including structural mechanics, heat transfer, fluid dynamics, particle tracing, and electromagnetics. By combining multiple physics interfaces within a single model, COMSOL allows researchers to simulate real-world systems where several physical effects interact simultaneously, rather than analyzing each in isolation. Typical use cases include thermal-structural coupling in mechanical components, electromagnetic heating, fluid-structure interaction, chemical reaction and transport processes, and acoustic-structure interaction.

The platform uses the finite element method (FEM) for spatial discretization and offers a graphical interface for building geometry, defining physics, meshing, solving, and post-processing results, all within one integrated workflow. COMSOL's modular architecture allows the core Multiphysics package to be extended with specialized add-on modules (e.g., CFD, Heat Transfer, Structural Mechanics, RF, Acoustics, Chemical Reaction Engineering), depending on the licensed configuration. Models can also be extended into custom applications using the Application Builder, and coupled with external tools such as MATLAB via LiveLink™ interfaces.

Current Licensed Software Version

COMSOL 6.4

Installation

The installation files and the installation document for the latest version of the software, along with network licensing information are available on our FTP server. COMSOL is also installed and available on our Linux clusters, BwUniCluster3.0 and Horeka to run computationally intensive simulations.

Note: Installation files for versions that are not listed above can be obtained upon request by contacting scs-contact∂scc.kit.edu.

Licensing

Network License: There are two separate COMSOL network license servers, both of which are currently active. The configuration details for both servers are provided in the network license configuration file available on the FTP server. During installation, please specify the appropriate license server name and port number as indicated in the configuration file, based on your intended use of the software. The two license servers serve distinct purposes and must be used accordingly:

• Floating Network License (FNL): Intended for non-commercial academic research activities conducted at KIT, including PhD research, Master's theses, Bachelor's theses, and other scientific projects.
• Class Kit License (CKL): Intended exclusively for teaching activities, such as lectures, courses, and exercises.

Please ensure that you select the appropriate license server based on your intended use of the software. Using either license for personal or commercial purposes is strictly prohibited. An active internet connection is required to use the software. If you are accessing it from outside the KIT network domain, please connect via VPN in order to reach the license server. For instructions on setting up and using the VPN, please refer to the link: Remote Access (VPN)

You may use, reproduce, modify, publicly display and perform, and distribute to the public this software (the "Application") and may permit others to do the same, subject to the following conditions:

1. Neither this Application nor any modified versions of this Application may be marketed or distributed in competition with any computer-aided design ("CAD") software product or as a stand-alone product for translating input to or output from any CAD software product.

2. Neither this Application nor any modified versions of this Application may be marketed or distributed as a replacement for any third party software program to which COMSOL Multiphysics and the add-on modules for which COMSOL Multiphysics provides an interface.

3. To the extent any other software programs must be used with this Application or with any modified version of this Application, you are responsible for ensuring compliance with all terms and conditions applicable to the use of those software programs.

4. This permission shall be included in all copies and modified versions of this Application.

5. If you modify this Application, the modification of this Application and the publication thereof must be in compliance with the then-applicable COMSOL Software License Agreement.

6. If you modify this Application, you shall identify your contributions within the permission included in the modified Application.

7. Neither you nor any other person or entity may use or distribute this Application, or any modified version of this Application, or exercise any of the rights granted here with respect to this Application, or any modified version of this Application, in violation of any applicable export or import law or regulation.

THE APPLICATION IS PROVIDED "AS IS" AND WITHOUT ANY WARRANTIES, WHETHER EXPRESS, IMPLIED, STATUTORY OR OTHERWISE, INCLUDING WITHOUT LIMITATION, WARRANTIES OF MERCHANTABILITY, NON-INFRINGEMENT, DESIGN, OPERATION, LACK OF VIRUSES, ACCURACY OR COMPLETENESS OF OUTPUT, LACK OF NEGLIGENCE, SECURITY, AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, CONSEQUENTIAL, EXEMPLARY, SPECIAL, INCIDENTAL OR PUNITIVE DAMAGES ARISING OUT OF OR RELATING TO THIS PERMISSION, REGARDLESS OF THE CAUSE OF ACTION, EVEN IF YOU HAVE ADVISED US OF THE POSSIBILITY OF SUCH DAMAGE.

This form of permission may be applied to Applications that you create, provided that your Application and the publication thereof complies with the then-applicable COMSOL Software License Agreement. However, if you apply this form to your Applications, you must change the copyright notice to reflect the correct copyright claimant(s). To the extent you modify this Application, you may distribute that modified version with your contributions offered under terms of your choosing and the original portions offered under this form of permission, provided, however, that your terms do not conflict with the then- current version of the COMSOL Software License Agreement.

COMSOL Multiphysics simulations with large memory or CPU requirements should be executed on the Linux HPC cluster in batch mode. Batch execution allows users to utilize multiple CPU cores, large memory resources, and long wall-clock times managed by the Slurm workload manager. We recommend you to use latest version of the software available on the cluster. Refer Running COMSOL in Parallel on Clusters for more information. 

Prerequisites

Before submitting a job to the cluster:

• Create your simulation model locally using COMSOL Multiphysics 6.4.

• Save the model as an .mph file.

• Copy the model and any additional input files (geometry files, material data, scripts, etc.) to your home or project directory on the cluster.

COMSOL Module on HPC Cluster

The cluster uses the Environment Modules system. To view all available COMSOL versions:

module avail cae/comsol

Load the latest version of software:

module load cae/comsol/6.4

Create and Submit Slurm Batch Script

Create a job script (for example, comsol_job.sh) with the following contents. This example script uses single node for running the job.

#!/bin/bash
#SBATCH --job-name=comsol
#SBATCH --nodes=1
#SBATCH --ntasks-per-node=2
#SBATCH --cpus-per-task=24
#SBATCH --partition=dev_cpu
#SBATCH --time=00:10:00
#SBATCH --mem=1G

module purge
module load cae/comsol/6.4

comsol batch \
    -usebatchlic \
    -np 20 \
    -tmpdir $TMP \
    -data $TMP/data \
    -autosave off \
    -inputfile backstep.mph \
    -outputfile backstep_result.mph \
    -batchlog job_${SLURM_JOB_ID}.log

Always try to use appropriate values for the slurm parameter. In the above shell script content,

• -np specifies the total number of computation threads used by COMSOL.

• -tmpdir stores temporary files on the local scratch filesystem for improved I/O performance.

• -data specifies the working directory used by COMSOL.

• -autosave off disables periodic autosave during the computation.

• -batchlog writes the solver output to a log file.

• -usebatchlic should only be used when running with a COMSOL Batch license (Floating Network License)

For running Multi-Node Jobs, COMSOL also supports distributed-memory (MPI) execution across multiple compute nodes if your license includes Cluster Computing.

#!/bin/bash
#SBATCH --nodes=2
#SBATCH --ntasks-per-node=2
#SBATCH --cpus-per-task=10
#SBATCH --partition=cpu
#SBATCH --time=02:00:00
#SBATCH --mem=90G

module purge
module load cae/comsol/6.4

comsol batch \
    -usebatchlic \
    -nn 2 \
    -np 20 \
    -tmpdir $TMP \
    -data $TMP/data \
    -autosave off \
    -inputfile backstep.mph \
    -outputfile backstep_result.mph \
    -batchlog job_${SLURM_JOB_ID}.log

Where

• -nn specifies the number of compute nodes.

• -np specifies the total number of processes or computation threads used by the simulation.

Submit the job to Slurm using

sbatch comsol_job.sh

Check the status of your job:

squeue

Best Practices

• Create and validate your model using COMSOL Multiphysics 6.4 before submitting it to the cluster.

• Always copy your .mph model and all required input files to the cluster before running.

• Use the local scratch directory ($TMP) for temporary files whenever possible to improve I/O performance.

• Choose the number of CPUs (-np) according to the allocated Slurm resources.

• Check the batch log after the simulation completes for solver progress and memory usage. COMSOL reports progress and memory consumption in the batch log during execution.