Flame stabilization has been of interest for many decades. Bluff-body flame stabilization has been incorporated in gas turbine engines as a means of secondary combustion in high-speed flows. The current work is focused on understanding vortex shedding and its contribution to both blow off and flame stability. Two modes of shedding, Kelvin-Helmoltz and Von-Karman, have been observed to play a major role in the stability and blow off of these bluff-body flames. Typically researchers have observed these modes visually but have been unable to quantify the effective contribution under various flow conditions. The present work is focused on the implementation of Proper Orthogonal Decomposition (POD) as a means of characterizing the energy and nature of these shedding modes as flames transition to acoustic instabilities and blow off. POD provides a new method of assessing the shedding mode and complements the pure visualization and vorticity calculations performed to date. POD is implemented on high-speed images of bluff-body flames at multiple equivalence ratios in an experimental test section. During this equivalence-ratio scan, the flame transitions to an acoustic instability. By incorporation of POD, the symmetric and asymmetric energy contributions through instability and blow off can be described.
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