Correlating hydrodynamic and acoustic fields in a turbulent combustor through community-based dimensionality reduction of vortical networks

We investigate the correlations between acoustic pressure oscillations and vortical interactions in the reactive field of a turbulent combustor susceptible to thermoacoustic instability. The spatial regions characterized by strong vortical interactions are recognized as vortical communities within the network space of weighted directed vortical networks. We subsequently reduce the dimensionality of these vortical networks using inter-community strengths and weighted centroids of the vortical communities. Our study reveals significant delayed correlations between inter-community interactions and acoustic pressure oscillations during the state of thermoacoustic instability. During the state of combustion noise, such correlations are lost due to incoherent spatiotemporal behavior in the reaction field of the combustor. Furthermore, these correlations provide insights into the critical regions detected within the reaction field during the states of intermittency and thermoacoustic instability in previous studies. Our work sheds light on the intricate relationship between vortical interactions and acoustic pressure behavior in turbulent combustors, offering insights into thermoacoustic instabilities and unsteady flows in fluid dynamics.