Imperial College London
Professor Xuesong Wu

ProfessorXuesongWu

Faculty of Natural Sciences, Department of Mathematics

Professor of Applied Mathematics
 
 
 
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Contact

 

+44 (0)20 7594 8494x.wu Website

 
 
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Location

 

738Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Wu:2014:10.1017/jfm.2014.525,
author = {Wu, X and Assier, RC},
doi = {10.1017/jfm.2014.525},
journal = {Journal of Fluid Mechanics},
pages = {180--220},
title = {Linear and weakly nonlinear instability of a premixed curved flame under the influence of its spontaneous acoustic field},
url = {http://dx.doi.org/10.1017/jfm.2014.525},
volume = {758},
year = {2014}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The stability of premixed flames in a duct is investigated using an asymptotic formulation, which is derived from first principles and based on high-activation-energy and low-Mach-number assumptions (Wu et al., J. Fluid Mech., vol. 497, 2003, pp. 23–53). The present approach takes into account the dynamic coupling between the flame and its spontaneous acoustic field, as well as the interactions between the hydrodynamic field and the flame. The focus is on the fundamental mechanisms of combustion instability. To this end, a linear stability analysis of some steady curved flames is undertaken. These steady flames are known to be stable when the spontaneous acoustic perturbations are ignored. However, we demonstrate that they are actually unstable when the latter effect is included. In order to corroborate this result, and also to provide a relatively simple model guiding active control, we derived an extended Michelson–Sivashinsky equation, which governs the linear and weakly nonlinear evolution of a perturbed flame under the influence of its spontaneous sound. Numerical solutions to the initial-value problem confirm the linear instability result, and show how the flame evolves nonlinearly with time. They also indicate that in certain parameter regimes the spontaneous sound can induce a strong secondary subharmonic parametric instability. This behaviour is explained and justified mathematically by resorting to Floquet theory. Finally we compare our theoretical results with experimental observations, showing that our model captures some of the observed behaviour of propagating flames.
AU  - Wu,X
AU  - Assier,RC
DO  - 10.1017/jfm.2014.525
EP  - 220
PY  - 2014///
SN  - 1469-7645
SP  - 180
TI  - Linear and weakly nonlinear instability of a premixed curved flame under the influence of its spontaneous acoustic field
T2  - Journal of Fluid Mechanics
UR  - http://dx.doi.org/10.1017/jfm.2014.525
UR  - http://hdl.handle.net/10044/1/17909
VL  - 758
ER  -
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