SINOPSIS

The effect of axial forcing on the flame/vortex breakdown interaction is studied, with particular focus on the Precessing Vortex Core (PVC). Large Eddy Simulations (LES), together with a filtered flamelet model describing the subgrid combustion, is performed to study a lean premixed flame undergoing mass flow fluctuations at half frequency of the PVC and 20% amplitude. Results show that in average forcing moves the recirculation zone upstream the combustor in the premixing tube. With the help of Proper Orthogonal Decomposition (POD) a detailed analysis of the dynamics of the central recirculation zone (CRZ) is performed and we show that the forcing triggers additional coherent structures. Extended POD is then applied to highlight the flow/flame interactions.