The flame stabilization and transition mechanisms in a moving burning droplet have been observed using high-speed imaging, when an external co-flow is imposed. The droplet flame is established based on the local flow characteristics near the droplet. Since the local flow characteristics are altered due to the external co-flow imposed, the flame shape and structure readjust by undergoing transitions and evolve temporally corresponding to the instantaneous local relative flow, established due to the external flow as well as the droplet motion. The different flame structures and the topological evolution of the flame shape depend on the instantaneous flame stabilization mode that is a consequence of the instantaneous flow structure around the droplet and the wake characteristics such as attached flow or symmetric eddies. These transitions also vary for different values of external co-flow velocity (ranging from less than droplet speed to greater than the instantaneous droplet speed), because of the local variation in Re as the droplet accelerates under different co-flow velocities.
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