Scalar flux modeling in turbulent flames using iterative deconvolution

02 Jul 2018

In the context of Large Eddy Simulations, deconvolution is an attractive alternative for modelling the un-closed terms appearing in the filtered governing equations. Such methods have been used in a number of studies for non-reacting and incompressible flows, however their application in reacting flows is limited in comparison. Deconvolution methods originate from clearly defined operations, and in theory can be used in order to model any un-closed term in the filtered equations including the scalar flux. In this study, an iterative deconvolution algorithm is used in order to provide a closure for the scalar flux term in a turbulent premixed flame by explicitly filtering the deconvoluted fields. The assessment of the method is conducted a priori using a three-dimensional direct numerical simulation database of a turbulent freely-propagating premixed flame in a canonical configuration. In contrast to most classical a priori studies, the assessment is more stringent as it is performed on a much coarser LES mesh which is constructed using the filtered fields as obtained from the direct simulations. For the conditions tested in this study, deconvolution is found to provide good estimates both of the scalar flux and of its divergence.