Acoustic Induced Instabilities of a V-Shaped Flame Anchored on a Rod

Abstract

Flame deformations in the near wake of an anchoring rod have been studied experimentally using laser tomography and laser ancmometry It is shown that the small scale structures occuring on V-shaped premixed flames are triggered by residual acoustic resonances of the burner when the flame is partly lifted off. This results from a shear layer instability of the wake, enhanced by a shielding effect of the rod on the acoustic field at the exit of the burner. The characteristic wavelength A/D varies as Re^−1/2

Keywords:

• Premixed flames
• instabilities
• anchored flames
• acoustic resonances