This summer, for the second time in a row, FELiCS took centre stage in our contribution to the 20th biennial Summer Program at Stanford University’s Center for Turbulence Research (CTR). Thomas and Marina from TU Berlin and Thorsten from the University of Stuttgart worked on site at Stanford, while Sophie provided invaluable scientific support from TU Berlin. The close collaboration between everyone involved was essential to the success of the project.
Over several intensive and inspiring weeks, we used FELiCS to investigate the linear stability of laminar flames, with a particular focus on thermodiffusive instabilities in curved and stretched flame configurations.
Our central goal was ambitious: to calculate dispersion relations—the growth rates of flame perturbations as a function of their wavenumber—directly from laminar flame profiles using linear stability analysis. We are thrilled that we achieved this goal. Our results demonstrate that FELiCS can capture the thermodiffusive mechanisms that determine whether flame perturbations grow or decay.
A particular focus of the project was the influence of flame curvature and stretch on the resulting instability characteristics. Real flames are rarely perfectly planar or unstretched, making these effects highly relevant for practical combustion systems. Understanding them is an important step towards incorporating instability dynamics into sub-grid-scale models for large-eddy simulations. Such models could ultimately account for unresolved flame instabilities without the enormous numerical cost of resolving them directly.
FELiCS formed the computational and methodological core of the project. It provided the framework for formulating, linearising, and solving the required stability problems. Seeing FELiCS successfully applied to this challenging problem was an exciting milestone and demonstrated the framework’s potential for the analysis of strained, stretched, and curved flames.
At the same time, the Summer Program gave us much more than the results we originally set out to obtain. The intense scientific exchange generated numerous ideas for the further development of FELiCS and opened up exciting new research directions.
One particularly intriguing idea is to use FELiCS to investigate the unsteady dynamics and flapping motion of wings. This would take the framework into an entirely new field of application—and it is a pathway we are determined to pursue.
Beyond the scientific achievements, the CTR Summer Program was an exceptional professional and personal experience. We reconnected with many old friends, met inspiring researchers from around the world, exchanged ideas across disciplines, and formed new collaborations. The atmosphere of openness, curiosity, and scientific ambition made the program truly memorable.
We sincerely thank Professors Parviz Moin and Beverley McKeon and the entire organising team for making the Summer Program possible. We are also very grateful to our host, Professor Hai Wang. Particular thanks go to the CTR postdoctoral researchers, whose expertise, commitment, and day-to-day support were invaluable throughout the program.
We returned from Stanford with successful results, exciting new research questions, and an abundance of ideas for the future of FELiCS. The Summer Program was not only a major step forward for our work on flame instabilities—it also showed us how much further FELiCS can go.