DNS and approximate deconvolution as a tool to analyse one-dimensional filtered flame sub-grid scale modelling

A procedure using approximate deconvolution and explicit filtering is discussed to evaluate topology based sub-grid scale (SGS) combustion models. A direct numerical simulation (DNS) database is first filtered, then a deconvolution operator constructed from the topology-based SGS model is applied, to compare the approximate three-dimensional fields against the exact ones. The DNS is obtained from an already well-resolved large eddy simulation (LES) of a bunsen flame, by refining the mesh up to full resolution of the reaction zones and the turbulent flow scales. The SGS model evaluation via approximate deconvolution is applied to a flamelet-like closure based on the tabulation of filtered one-dimensional flames. The various sources of errors are analysed in a statistical manner in terms of flame topology. Aside from the a priori analysis, results from LES are also reported with the one-dimensional flame de convolution and compared against those resulting from an approximate three-dimensional deconvolution, confirming the need for accounting for the full 3D flame dynamics in SGS modelling. All the study is performed with tabulated detailed chemistry. (C) 2016 The Combustion Institute. Published by Elsevier Inc. All rights reserved.