ARCHER2 Calendar January 2026

Formation of a Reverse Kármán Vortex Street in the Wake of a Morphing Wing

Miss Hibah Saddal, Chandan Bose, Department of Aerospace Engineering, University of Birmingham

* * * Winning Image, ARCHER2 Image and Video Competition 2025 * * *

A fully flexible aerofoil, with varying flexibilities at the leading and trailing edges, mitigates the effect of gust through passive morphing. The flexible morphing foil interacts with incoming fluid flow, creating a symmetrical reverse Kármán vortex street in its wake through the alternate shedding of opposite sense vortices resulting from the leading- and trailing-edge vortex interactions. Capturing this required high-fidelity simulations on the Archer2 HPC system by coupling OpenFOAM (finite-volume method) as the fluid solver with CalculiX (finite-element method) as the solid solver. This wake pattern, formed by a coherent train of vortices with opposite sense of rotation at high Strouhal number is representative of thrust generation. Visualised using finite-time Lyapunov exponent, this image showcases the benefits of dynamic fluid-structure interaction.

This image was published on the January page of the ARCHER2 2026 printed calendar.