An <i>a priori</i> analysis of the structure of local subfilter-scale species surrounding flame fronts using direct numerical simulation of turbulent premixed flames

An a priori analysis of subfilter-scale (SFS) species structure important to estimate chemical reaction rates in large-eddy simulation (LES) is performed using direct numerical (DNS) turbulent premixed flame at turbulence Reynolds number Re0=329 and Karlovitz Ka0=7.23 with semi-detailed finite-rate chemistry. Differences between the complete extracted from DNS those estimated LES-filtered variables are quantified. The spatial distributions these differences found be localized regions surrounding front for representative reactions. Within regions, variations localization relative flame, scale, magnitude SFS concentrations quantified, mean determined. two groupings: “single-banded” characterized by one distinct peak “double-banded” peaks opposite signs. Species that produced consumed within such as CH2O HCO observed have single-banded structure, displaying frontal behavior n-C7H16 OH double-banded on average. local impacted neighboring flame-flame interactions well curvature. impacts strong when has “large” length scales concentration significantly displaced front. Curvature effects shown high curvature flame.