1. Ratio 1951 Nicholson and Field21V-Gutter
2. Second, the measurements of Nair and Lieuwen32and Kiel18clearly indicate the presence of a nearfield sinuous wake, and possibly, therefore, vortex shedding, at higher dilatation ratios (Tb/Tu~5-6 and 2.7, respectively) than Erickson et al.'s16simulations suggest the BVK instability should emerge. This sinuous wake appeared after the presence of significant extinction events along the flame. A hypothesis to explain this behavior is that in the higher dilatation ratio case, decreases in fuel/air ratio alone are not sufficient to move the dilatation ratio into a regime where the BVK instability exists. In this case, the presence of localized extinction events is a necessary precursor. Localized flame extinction results in cooling of the bluff body wake by the recirculation of unburned reactants into it, which may locally push the flow into a region where the BVK instability can persist. However, this is a hypothesis which requiresvalidation. Third, while there exists substantial data and computations of near blowoff flames, there is very little available results for flames that are actually blowing off. As such, the blowoff mechanism described above is necessarily a hypothesis which requires data that can be used to critically evaluate it. Further measurements and computations of flamesduring theactual blowoff event areneeded.