Statistics of local flame-flame interactions in flame interaction zones of two v-flames

The flame structure and dynamics of interacting turbulent premixed flames are dependent on interactions between the flow fields and scalar fields of individual flames. Studies have shown that local flame-flame interactions introduce a variety of effects on flame structure and propagation by changing the statistics of flame curvature, displacement speed, flame area fluctuations, and stretch-rates. The topology of interaction events can vary significantly in the interaction zones of turbulent flames. These interactions can also result in the formation of unburned and burned gas pockets. Understanding the behavior of these interaction events is of important to capture the destruction of the flame surface to develop better sub-grid scale turbulent combustion models for enhancing the design and operation of modern combustion devices. The goal of this study is to characterize the behavior of two interacting V-flames and the local flame-flame interaction characteristics in their interaction zones. High-speed OH-planar laser-induced fluorescence (OH-PLIF) is implemented to obtain instantaneous flame front locations of rod-stabilized V-flames in a dual-burner experiment. A non-rigid image registration technique is applied to flame images to track the topological changes occurring in small time steps. In particular, results are presented for the dynamics of the interaction zones of these flames to illustrate that large-scale oscillations are important in the occurrence of small-scale flame-flame interactions. Lower arrival frequencies for flame-flame interactions are widely distributed along the streamwise direction, connecting the large-scale global behavior to the sub-grid level behavior of turbulent V-flames.