Abstract
The response of a stretched cylindrical diffusion flame to a sinusoidal oscillating air flow was investigated experimentally. The cylindrical flame used in this study had a concave curvature with respect to the fuel stream. The methane diluted with nitrogen was used as fuel. The oscillating frequency of the air flow was varied ranging from 10 to 250 Hz. Following results are obtained: (1) Fluctuating amplitude of the flame curvature decreases with an increase in frequency. (2) Oscillating amplitude of the flame luminosity has a maximum value with respect to the frequency. (3) In a certain frequency range, the variation width of the luminosity of the dynamic flame is larger than that of the static flame in the velocity range corresponding to the fluctuation.
