Morphology of wrinkles along the surface of turbulent Bunsen flames - Their amplification and advection due to the Darrieus-Landau instability

Meng Zhang, Advitya Patyal, Zuohua Huang, Moshe Matalon

Research output: Contribution to journalArticlepeer-review

Abstract

The morphological development of wrinkles along the surface of a Bunsen flame in a weakly-turbulent flow is investigated, with turbulence added solely to disturb the flame front. The resulting flame-flow interactions are examined using a hybrid Navier-Stokes/front-tracking methodology within the context of the hydrodynamic theory. Topological markers based on the skewness of curvature are introduced to distinguish between sub- and super-critical conditions, or the absence/presence of the Darrieus-Landau instability, respectively. We show that for sub-critical conditions disturbances created along the flame surface are dampened when convected downstream along the flame front, and the flame surface is only weakly perturbed. For super-critical conditions, on the other hand, disturbances of the flame front are amplified when advected downstream leading to a highly corrugated surface and a flame brush of increasing thickness. A measure of these dramatic changes is included in the mean local stretch rate which, when properly modulated by a Markstein length, directly affects the turbulent flame speed.

Original languageEnglish (US)
Pages (from-to)2335-2343
Number of pages9
JournalProceedings of the Combustion Institute
Volume37
Issue number2
DOIs
StatePublished - 2019

Keywords

  • Bunsen flames
  • Darrieus-Landau instability
  • Inclined flames
  • Markstein length
  • Turbulent premixed flames

ASJC Scopus subject areas

  • General Chemical Engineering
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

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