Analysis of flame curvature evolution in a turbulent premixed bluff body burner

The physical mechanisms responsible for flame curvature evolution of a methane-air premixed flame attached to a bluff-body burner have been investigated using a high-fidelity flame-resolved three-dimensional simulation database. The contributions to the mean curvature generation due to the fluid flow motion and due to a combination of flow and flame propagation induced strain rates have been analyzed in detail and dominant contributions in different zones (reactants, flame, and products) of the flame have been identified. The effect of fluid flow on the mean curvature evolution is important on the unburned gas side, whereas the flame propagation dominates the mean curvature evolution in the reaction region and toward the hot products. The statistical contributions of the mean curvature transport equation have been analyzed in terms of the iso-scalar surface geometry, characterized by the mean and Gauss curvatures. This information has subsequently been used to provide physical insights into the dominant mechanisms of curvature evolution for different flame topologies.