Experimental study on the interaction between non-reacting swirling jets

Modern gas turbine combustors employ swirl flows for flame stabilization. In such systems, the dynamic feature of the swirl flows govern critical processes such as mixing of the reactants, ignition dynamics, and the dynamics of flames. The latter in turn has a governing influence on the (thermoacoustic) stability of the combustor. Often combustor configurations employ an array of swirl-stabilized flames, where the interaction between flames has a critical
influence on the said processes. In this study, we look at the interaction of non-reacting swirl flows. In particular, the focus is on how the coherent structures associated with the self-excited helical instability of the swirl flows is modified when two swirling jets are placed close to each other. We also look how vortical fluctuations induced in the jets with the introduction of acoustic forcing interact. Time-resolved Schlieren imaging is employed for the experiments and the obtained sequence of Schlieren snapshots is analysed via statistical tools to extract coherent flow structures and to study their interaction.