Large eddy simulations (LES) of an atmospheric swirled burner using a Partially Stirred Reactor (PaSR) closure are performed to investigate the hydrodynamic modes governing flow–flame interactions under hydrogen enrichment. Three technically premixed methane–air flames with increasing level of hydrogen are considered, Flame 1 (0% \(\text{H}_2\) ), Flame 2 (40% \(\text{H}_2\) ), and Flame 3 (50% \(\text{H}_2\) ). Simulations show good agreement with experimental data, particularly in terms of velocity fields and overall flame behaviour. Distinct flame topologies are observed, with Flame 1 exhibiting a lifted M-shaped structure and Flames 2 and 3 forming attached V-shaped flames. Proper Orthogonal Decomposition is applied to identify the dominant coherent structures. Flame 1 is strongly governed by a precessing vortex core (PVC), while Flames 2 and 3 exhibit weaker, more distributed structures. A secondary structure in Flame 1 is identified as a harmonic of the primary PVC, whereas analysis of the respective vortices in hydrogen-enriched Flames 2 and 3 suggests an independent nature. Overall, hydrogen enrichment modifies the strength and coherence of hydrodynamic structures and promotes a partial decoupling between mixing and flow dynamics.
