The NextSim interview series aims to introduce readers to the people behind our research. Stefan Görtz, an advanced numerical methods expert and head of Center for Computer Applications in Aerospace Science and Engineering at the German Aerospace Center (DLR) is involved in NextSim´s work in Technology Verification, Validation, and Error Quantification. Learn more about his thoughts and motivations regarding the project.

What is your position at DLR and what is your research area?

I am currently the head of the Center for Computer Applications in AeroSpace Science and Engineering (C²A²S²E) at the DLR Institute of Aerodynamics and Flow Technology in Braunschweig, Germany. The C²A²S²E department is engaged in research and development of advanced numerical methods and software solutions for multidisciplinary simulation and optimization of aircraft, including the development of the next generation flow solver CODA, which we develop in collaboration with the French Aerospace Lab ONERA and Airbus. Our research activities include physical modeling of complex flows, the development of advanced solution algorithms for numerical flow simulation, as well as the integration of all relevant disciplines. We also develop efficient optimization strategies and methods for data-driven modeling and simulation and quantifying uncertainties based on state-of-the-art high-fidelity methods. Customizing numerical methods for optimal efficiency on high-performance computer clusters, which is the main driver for our NextSim activities, is of particular importance to the department.

You are leading the work package on Technology Verification, Validation, and Error Quantification. Could you explain why this is important for NextSim?

Correct, DLR is in charge of Technology Verification, Validation, and Error Quantification in NextSim, even though I do not lead this work package myself. This work package is crucial to make sure that CODA, the next-generation computational fluid dynamics (CFD) solver that is being re-engineered in Nextsim to demonstrate its readiness for running efficiently on Exascale computers, can be easily extended and maintained and that a high level of software quality is guaranteed, which will contribute to industrializing the code and user acceptance and confidence in the results.

What would you have done if you were not a researcher?

If I didn’t suffer from allergies and didn’t have bad eyesight, I probably would have realized my childhood dream and become a professional pilot. But I really enjoy being a researcher instead and contribute to some extend to designing better aircraft that I can fly in as a passenger.

Have you encountered any challenges in pursuing your research career?

Well, I never really aspired to a career in research, and things just happened the way they did (thanks to my supervisors and mentors). But I have to admit that completing my PhD was a challenge because I myself was not satisfied with my performance and would have continued to try to meet my own standards if my PhD supervisor had not told me to consider the PhD as an intermediate step on the career ladder and finally complete it. I am forever grateful to him for encouraging me to do the PhD, but also for guiding me to the end.

How is your experience with NextSim so far?

NextSim is very well managed, there are regular technical committee meetings, general assemblies, work package meetings, but all of our meetings so far, including the kickoff meeting, have been virtual, which is a pity because research and collaboration is fueled by personal exchange with others. I am glad that many project participants will be able meet at the ECCOMAS 2022 conference in Oslo, where NextSim is organising a minisymposium titled “Towards Next Generation of Industrial Aerodynamical Simulation Tools”.

What do you hope NextSim can achieve beyond the life of the project?

I am convinced that NextSim will make a lasting contribution to establishing CODA as the European platform for next-generation CFD, analysis and design.

What advice would you give young researchers who would like to follow in your footsteps?

Live your dreams, never give up. You can make them come true. And don’t be afraid to ask – most other researchers are happy to discuss with you and share their own experience and knowledge with you.