A priori analysis of lean turbulent premixed hydrogen combustion DNS simulation : FGM testing and sub-grid scale analysis

With the aim of assess Flamelet Generated Manifolds technique in lean hydrogen combustion we will investigate the probability density distributions by processing the DNS data of such flames, in which detailed chemistry is used, comparing them with a set of perturbed flamelet solutions. It is shown the one-dimensional results with increasing stretch rate or equivalence ratio can mimic in the correct way most of the DNS data. The essential extinguishing behavior at negative stretch in cusp regions has to be studied further. A second part of this article is dedicated to a subgrid scale analysis of the above flame. Usually in combustion a -pdf is used to describe the subgrid probability density distribution of the progress variable, we will therefore investigate the DNS subgrid scale probability density distributions in direct comparison with the derived -pdf.