On Hydrodynamic Instability of Stretched Flames

Abstract

The recent result on the diffusive instability of a planar premixed gas flame sustained in the stagnation-point flow are carried over on the hydrodynamic (Darrieus-Landau) instability. Similar to the former case the planar flame of the infinite aspect length-scale is unconditionally stable for any flow induced stretch however small. Yet in finite geometries occuring in numerical and laboratory experiments the flame may well become unstable provided the imposed stretch is weak enough. It is argued that the effect may be related to the formation of a non-steady multiple cusp structure often observed in large-scale flames.

keywords::

• Counterflow flames
• instabilities in flames