How to push the boundaries of CFD modeling and the need to move towards democratization of numerical simulation

Read on to learn about the latest research findings from the global CFD community shared at the 9th OpenFOAM Conference

by Roger Almenar
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How is it possible to efficiently manage the growing complexity and number of regulations and certification procedures facing OEMs and suppliers across industries when they must have early confidence in the safe, clean, and productive performance of their new lightweight, electrified designs?

With this background, the 9th OpenFOAM1 Conference took place earlier in October but before I start sharing with you the key takeaways from industry leaders, let me share a thought-provoking citation of two physicists: “When I meet the Lord, I would like to ask him two questions: why relativity? And why turbulence? I believe he will have an answer for the first.” This well-known saying, credited to one of two physicists, Werner Heisenberg or Horace Lamb, is probably apocryphal, but it literally reflects the difficulties of understanding the convoluted behavior of turbulence in fluid flows. As Dr. Philippe Spalart, former Senior Technical Fellow at Boeing and NASA, presented during his keynote, turbulence is “that elephant in the room that everybody is trying to study”. As if being able to see the full picture wasn’t a big enough challenge already, “Nature doesn’t ask your permission; she does not care about your wishes, and whether you like her laws or not, you are bound to accept her as she is, and consequently all her conclusions”. [i] So, in a nutshell, no matter how many physical models we develop, nature doesn’t care about mathematical equations and continues to keep us on our toes. Because of this conundrum, and the fact that we cannot change the characteristics of nature, the only option we have for better predictivity is to bring human experiences together and build out the technical foundation to eventually be able to see the entire room and what’s behind the elephant standing in it.

Democratization of simulation and virtual testing is key

Open research and collaboration in different areas of numerics, multiphase & turbulence modeling, supercomputing, and application areas is the way many academic and industrial leaders are defying these challenges using OpenFOAM - the open source CFD code developed, maintained and QA-released every six months and made available to the community by ESI Group.

For a long time, OpenFOAM has been a platform for scientists and engineers to virtually experiment with technological innovations and digitally test flows in real-world scenarios. By making highly scalable solutions accessible to a broad user base globally and across industries, the software has been driving the democratization of numerical simulation and contributes to the understanding that digital model results increasingly serve as the reference, pushing physical test to the back burner.

There isn’t a more economical or sustainable alternative to cost- and time intense physical trials than simulating and virtually testing fluid dynamics problematics.

Establishing sustainable digital practices across the entire value chain

The community met virtually at the annual OpenFOAM Conference to share insights into the latest results from their work with the software, whether for state-of-the-art industrial applications or research & innovation. The conference featured 40 presentations between plenary and parallel sessions, with GNS Systems and NVIDIA as main sponsors.

Here are some of my key takeaways for the next steps on the path to democratization:

  • Dr. Akshai Runchal, CEO and Founding Partner for ACRi Group, who has witnessed the growth of Computational Fluid Dynamics (CFD) from its birth, emphasized the role of CFD modeling in facilitating early informed decision-making processes. Looking into the future, he expects the easy-to-use job-to-be-done apps, physics informed neural networks integrated with artificial intelligence and deep learning, supplemented by Digital Twin technologies and Virtual Reality.
  • Dr. Phillippe Spalart highlighted the need for “push-button”, robust and accurate solutions for non-expert CFD users and for “natural intelligence” and open collaboration to continue the progress in the knowledge of turbulence. He also advocated for more “human intelligence” to continue the progress in the knowledge of fluid dynamics.
  • The most important updates for the widespread community from the OpenFOAM Governance included the OpenFOAM® Journal, infrastructure, blind peer review processes and the tutorial collection for those new to OpenFOAM.
  • During the OpenFOAM Governance’s Technical Committee’s panel discussion, several exciting initiatives in various areas were detailed. As the community grows, the proposal to increase the number of special interest groups for oil & gas, turbomachinery and data is also under discussion.
  • For the first time ever, there was a session dedicated to Artificial Intelligence and OpenFOAM applications, realizing the potential of Model Order Reduction applied to aerodynamics, ventilation & air quality, machine learning, and optimization with neural networks. In previous conferences, there have been keynote and technical presentations showing the progress of research and innovation, led by ENSAM and ESI Group, which has been industrialized in the meantime. 
CFD MOR results
Contamination spread in a public transport cabin (left) and generation of the reduced model using artificial intelligence/sPGD (right)
  • Dr. Bariş Biçer of Turkish Aerospace Industries highlighted how they use the tool for validating aerodynamics of several aircraft configurations, propellers and object drops.
Vortices
Vortices (Q-criterion) generated by propellers in action
  • Responding to disruptive challenges in the automotive industry [name] from the National Technical University of Athens demonstrated the need to shape optimization capabilities in order to maximize driving ranges and computing performance in WLTP-conforming rotating wheel aerodynamics towards vehicle certification. This was also shown by my colleague Sebastien Vilfayeau in collaboration with Volkswagen and Audi. The Aerodynamic App by ESI Group is yet another example of democratization in the automotive industry.
Shape Optimization
Automated shape optimization process using Adjoint Optimisation functionality
  • OpenFOAM is also applied beyond the automotive and aerospace industries. We’ve seen impressive findings about health and air quality such as:
    • blood modeling
    • dispersion of saliva droplets & ventilation
    • work done to improve air quality
    • demonstration of the VentESI App enabling non-expert users to predict air quality like a CFD expert
  • High performance computing is rapidly evolving not only through the exaFOAM project (with the goal of overcoming the limitations of CFD in massive parallel HPC architectures, realizing the vision of exa-scale computing with OpenFOAM) but also by opening the ‘research door’ for maintainable GPU computing.

This conference has highlighted that the OpenFOAM platform is propelling forward with several bright lights in its future and a growing community of brilliant minds who collaboratively work on new models that will one day reveal the full picture. We’ve seen amazing progress and achievements in the past decade, and I am excited to see my CFD peers share new applications at next year’s user event. Meanwhile, send us a note to join the global OpenFOAM community to grow your ecosystem and sign-up for one of our training courses to improve your simulation capabilities. 


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