Self-Turbulization in Cellularly Unstable Laminar Flames
It has been suggested that a cellularly unstable laminar flame, which is freely propagating in unbounded space, can accelerate and evolve into a turbulent flame with the neighbouring flow exhibiting the basic characteristics of turbulence. Famously known as self-turbulization, this conceptual transition in the flow regime, which arises from local interactions between the propagating wrinkled flamefront and the flow, is critical in extreme events such as the deflagration-to-detonation transition (DDT) leading to supernova explosions. Recognizing that such a transition in the flow regime has not been conclusively demonstrated through experiments, in this work, we present experimental measurements of flow characteristics of flame-generated 'turbulence' for expanding cellular laminar flames. The energy spectra of such 'turbulence' at different stages of cellular instability are analysed. A subsequent scaling analysis points out that the observed energy spectra are driven by the fractal topology of the cellularly unstable flamefront.
Z. Liu et al., "Self-Turbulization in Cellularly Unstable Laminar Flames," Journal of Fluid Mechanics, vol. 917, Cambridge University Press, Jun 2021.
The definitive version is available at https://doi.org/10.1017/jfm.2021.330
Mechanical and Aerospace Engineering
Keywords and Phrases
flames; instability; transition to turbulence
International Standard Serial Number (ISSN)
Article - Journal
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25 Jun 2021