openCFS (Coupled Field Simulation) is a finite element-based multi-physics modelling and simulation tool. With about 20 years of research driven development, the core of openCFS is used in scientific research and industrial application. The modelling strategy focuses on physical fields and their respective couplings.
free and open source
under the MIT license, openCFS can be used by anyone, even commercially (as long as you include the original copyright and license notice in any copy of the software/source). You can check out the source code or download the latest release for Linux or Windows.
state of the art features
range from capabilities for various physical fields and their couplings, non conforming grid techniques, and structural optimization, to flexible data exchange with third party software, scriptable XML input, and powerful built-in third party libraries.
quick to learn
organised in an association devoted to the promotion of the software. Members range from university researchers at TU Wien, FAU, TU Graz over individuals and students to companies applying openCFS to industrial problems.
for openCFS is available through the company EnSimTech UG which was founded in 2020. EnSimTech allows commercial users of openCFS to benefit from commercial support, integration and adaptions of openCFS to fit the commercial customer needs.
May 2021 - Aeroacoustic Simulations of Low-pressure Axial Fan for Battery Cooling Units
The new release of openCFS-2021S is available online under the MIT license.
This autumn, the annual users meeting will be in Vienna from Thursday, September 23 until Friday, September 24. Presentation request should be sent to email@example.com.
Recent contributions to openCFS
Recently, we have provided support for intel compilers and optimized the openCFS builds for native architectures.
- Support for intel compilers (c++ and Fortran)
- Optimized builds for native architecture
- Freidhager, C., et al. Simulationen von Strömungsakustik in rotierenden Bauteilen zur Entwicklung von Antriebskonzepten der Autos der Zukunft. Elektrotech. Inftech. (2021). 10.1007/s00502-021-00887-0
- Maurerlehner, P., et al. Efficient numerical simulation of the human voice. Elektrotech. Inftech. (2021). 10.1007/s00502-021-00886-1
- K. Roppert, et al. Sliding Non-Conforming Interfaces for Edge Elements in Eddy Current Problems, in IEEE Transactions on Magnetics, 57, 3, 1-6, (2021) 10.1109/TMAG.2020.3049059.
- Floss, S., et al. Micro-perforated panels for noise reduction. Elektrotech. Inftech. (2021). 10.1007/s00502-021-00889-y
- Toth, F., et al. Acoustics on small scales. Elektrotech. Inftech. (2021). 10.1007/s00502-021-00875-4
by S. Schoder: firstname.lastname@example.org , A. Wurzinger, C. Freidhager, M. Kaltenbacher, IGTE, TU Graz
HVAC System Simulation
Future power units of cars (the electric motor, battery, fuel cell) generate little noise during operation. Consequently, the noise of auxiliary units (cooling fan of a battery unit, the turbocharger of fuel cells  becomes an essential task of the developing process. Since performing robust measurements are costly and time-consuming, the presented validated simulation workflow enhances development and research .
Details on the Study
Within this finished research project, we investigated the individual steps of the hybrid aeroacoustic workflow in detail. Based on existing benchmark data for low-pressure axial fans , the perturbed convective wave equation (PCWE) and the Ffowcs Williams and Hawkings analogy Farassat’s 1A (FWH) are analyzed. We performed a mesh convergence study and altered the turbulence modeling approach (visualization see Fig. 1).
Fig. 1: Q-criterion at instantaneous time, which is showing the turbulent structures of the tip flow.
The detached eddy simulation model and a grid of 23.4million cells delivered the most accurate sound radiation (see Fig. 2). The validation of the results allows us to conclude that the fluctuating flow pressure is the relevant flow-convergence criteria, motivated by the fact that it is the dominant source term both for PCWE and FWH.
Fig. 2: Sound propagation visualization.
Furthermore, we showed the robustness of the developed grid interpolation techniques  using the Richardson extrapolation. Considering the short duct, we found that for frequencies below 700Hz, FWH and PCWE deliver a comparable accuracy of sound prediction . However, for sources at a higher frequency, the directivity of the propagation matters (which the PCWE accounts for). Since most industrial applications have complicated geometries, including in-duct systems, the PCWE (discretized by the finite element method) is preferable.
 Schoder, S. et al. "Computational aeroacoustics of the EAA benchmark case of an axial fan." Acta Acustica 4.5 (2020): 22.10.1051/aacus/2020021
 European Acoustics Association: Benchmark Cases for Computational Acoustics. 2017.
 Schoder, S. et al. "Application limits of conservative source interpolation methods using a low Mach number hybrid aeroacoustic workflow." JTCA 29.1 (2021). 10.1142/S2591728520500322
Model Order Reduction
Association for the promotion of the software
Verein zur Förderung der Software openCFS
The association "Verein zur Förderung der Software openCFS" has been founded in 2020 and its main goal is the promotion of the open source software openCFS. The main objectives of the association are
- Comprehensive maintenance and further development of the open source software openCFS
- Promotion of the use of openCFS for scientific problems which are solved with the help of numerical simulation, thus leading to new, innovative products for the benefit of mankind (Technology for People)
- Promotion of the scientific documentation of openCFS and the use of openCFS in higher education
- Promotion of young scientists, especially students at universities in Austria and Germany and worldwide, in the field of numerical simulation of complex technical systems
User prize presentation
Once a year a user prize is awarded within the framework of a user meeting.
Developer prize presentation
Once a year a developer prize is awarded within the framework of a user meeting.
Several memberships are available that allow supporting the development and marketing of openCFS.
The regular membership entitles the member to actively support the openCFS development, take part at developer meetings as well as user meetings. The membership includes the right to vote at any meeting of the association.Yearly membership fee: 30 €
The associate membership entitles the member to actively support the openCFS development, take part at developer meetings as well as user meetings. However, a right to vote at any meeting of the association is not included.Yearly membership fee: 20 €
The commercial membership entitles the member to actively support the openCFS development, take part at developer meetings as well as user meetings. Commercial members do not obtain a right to vote at any meeting of the association.
The advantage of a commercial membership are reduced participation fees for events of the association as well as discounted sponsoring rates.Yearly membership fee: 200 € (small company), 500 € (medium company), 1000 € (large company)
The student membership entitles the academic student member to actively support the openCFS development, take part at developer meetings
as well as user meetings.
Student members do not obtain a right to vote at any meeting of the association.
Frequently Asked Questions
Which license is openCFS using?
openCFS is using the MIT license thus allows to easily use the software in commercial companies.
Is commercial support available?
Will be available soon.
Is it possible to enhance the features by openCFS?
Yes, the features of openCFS can be easily enhanced in two different ways:
Customization and workflow integration is carried out by EnSimTech UG.
New physical domains or coupling can be implemented using a collaboration with the academic partners.