Mellado, J. P. and Sarkar, S. and Pantano, C. (2003) Reconstruction subgrid models for nonpremixed combustion. Physics of Fluids, 15 (11). pp. 3280-3307. ISSN 1070-6631 http://resolver.caltech.edu/CaltechAUTHORS:MELpof03
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Large-eddy simulation of combustion problems involves highly nonlinear terms that, when filtered, result in a contribution from subgrid fluctuations of scalars, Z, to the dynamics of the filtered value. This subgrid contribution requires modeling. Reconstruction models try to recover as much information as possible from the resolved field Z, based on a deconvolution procedure to obtain an intermediate field ZM. The approximate reconstruction using moments (ARM) method combines approximate reconstruction, a purely mathematical procedure, with additional physics-based information required to match specific scalar moments, in the simplest case, the Reynolds-averaged value of the subgrid variance. Here, results from the analysis of the ARM model in the case of a spatially evolving turbulent plane jet are presented. A priori and a posteriori evaluations using data from direct numerical simulation are carried out. The nonlinearities considered are representative of reacting flows: power functions, the dependence of the density on the mixture fraction (relevant for conserved scalar approaches) and the Arrhenius nonlinearity (very localized in Z space). Comparisons are made against the more popular beta probability density function (PDF) approach in the a priori analysis, trying to define ranges of validity for each approach. The results show that the ARM model is able to capture the subgrid part of the variance accurately over a wide range of filter sizes and performs well for the different nonlinearities, giving uniformly better predictions than the beta PDF for the polynomial case. In the case of the density and Arrhenius nonlinearities, the relative performance of the ARM and traditional PDF approaches depends on the size of the subgrid variance with respect to a characteristic scale of each function. Furthermore, the sources of error associated with the ARM method are considered and analytical bounds on that error are obtained.
|Additional Information:||©2003 American Institute of Physics. Received 31 January 2003; accepted 17 July 2003; published online 16 September 2003. Partial support for the authors was provided by AFOSR through Grant No. F49620-96-1-0106 and Lawrence Livermore National Laboratory through the Student Employee Graduate Research Fellowship Program. This work was supported in part by a grant of HPC time at the Naval Oceanographic Office Department of Defense Major Shared Resource Center.|
|Subject Keywords:||combustion; flow simulation; fluctuations; deconvolution; chemically reactive flow|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||07 Aug 2006|
|Last Modified:||26 Dec 2012 08:58|
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