Sharpe, G.J. and Falle, S.A.E.G. (2006) Nonlinear cellular instabilities of planar premixed flames: numerical simulations of the Reactive Navier-Stokes equations. Combustion Theory and Modelling, 10 (3). pp. 483-514. ISSN 1741-3559
Available under licence : See the attached licence file.
Two-dimensional compressible Reactive Navier-Stokes numerical simulations of intrinsic planar, premixed flame instabilities are performed. The initial growth of a sinusoidally perturbed planar flame is first compared with the predictions of a recent exact linear stability analysis, and it is shown the analysis provides a necessary but not sufficient test problem for validating numerical schemes intended for flame simulations. The long-time nonlinear evolution up to the final nonlinear stationary cellular flame is then examined for numerical domains of increasing width. It is shown that for routinely computationally affordable domain widths, the evolution and final state is, in general, entirely dependent on the width of the domain and choice of numerical boundary conditions. It is also shown that the linear analysis has no relevance to the final nonlinear cell size. When both hydrodynamic and thermal-diffusive effects are important, the evolution consists of a number of symmetry breaking cell splitting and re-merging processes which results in a stationary state of a single very asymmetric cell in the domain, a flame shape which is not predicted by weakly nonlinear evolution equations. Resolution studies are performed and it is found that lower numerical resolutions, typical of those used in previous works, do not give even the qualitatively correct solution in wide domains. We also show that the long-time evolution, including whether or not a stationary state is ever achieved, depends on the choice of the numerical boundary conditions at the inflow and outflow boundaries, and on the numerical domain length and flame Mach number for the types of boundary conditions used in some previous works.
|Copyright, Publisher and Additional Information:||This is an electronic version of an article published in Combustion Theory and Modelling, Volume 10, Issue 3 June 2006 , pages 483 - 514. Combustion Theory and Modelling is available online at: http://www.informaworld.com|
|Keywords:||Combustion instabilities, numerical methods, stability analysis|
|Institution:||The University of Leeds|
|Academic Units:||The University of Leeds > Faculty of Maths and Physical Sciences (Leeds) > School of Mathematics (Leeds) > Applied Mathematics (Leeds)
The University of Leeds > Faculty of Engineering (Leeds) > School of Mechanical Engineering (Leeds) > Institute of Engineering Thermofluids, Surfaces & Interfaces (iETSI) (Leeds)
|Depositing User:||Dr GJ Sharpe|
|Date Deposited:||04 Mar 2008 10:48|
|Last Modified:||08 Feb 2013 17:05|
|Publisher:||Taylor and Francis|