Network structure of turbulent premixed flames.

In this paper, a generalized description of the complex topology of turbulent premixed flames stabilized in a model gas turbine combustor is obtained using network analysis. Networks are created using the visibility algorithm applied to points on the flame edge obtained from Hydroxyl radical (OH)-Planar Laser Induced Fluorescence images of turbulent premixed flames. The network structure thus obtained showed the emergence of a few massively connected nodes which were found to represent the folded regions of the flame front. These nodes, which are called the hubs of the network, are vital for determining the overall structure of the flame front. Degree distribution of the formulated networks is used to characterize the flame-turbulence interaction inherent in the system. Turbulent flame front networks were found to be rigid enough to be unaffected by random perturbations but highly vulnerable towards coordinated removal of hubs or folds. These findings could serve as the first network-analytic approach to characterize turbulence-flame interaction dynamics with the use of a flourishing network theory, which enhances ongoing works based on vortex dynamics, hydrodynamic stability, and thermo-acoustic instability.