The Effect of High-Frequency Periodic Disturbances on Axisymmetric Wake Diffusion Ffames

Abstract

A theoretical analysis of the response of axisymmetric wake diffusion flames to high frequency periodic velocity oscillations imposed at their boundaries is presented. The effect of small amplitude oscillations on the flame, as derived from a linearized theory, is shown to be small. Significant non-linear effects which become important as the amplitude of oscillations increases are predicted using an integral method. In correspondence with empirical results reported elsewhere, the analysis shows that large amplitude oscillations tend to shorten the flame length, to cause a faster decay of the mean velocity field and to intensify the mixing processes in the flame.