Inspecting Lagrangian coherent structures in turbulent combustion simulations

Abstract

In this study, fnite time Lyapunov exponent (FTLE) fields from turbulent reacting flows are evaluated. The unsteady turbulent velocity field is obtained from large-eddy simulations, and reacting (DLR Flame A) and non-reacting unconfined jet configurations are considered. Backward FTLE analysis on the velocity field is performed, and the anal- ysis shows that the ridges approximate the flow structure associated with the organized fuid structure. To examine the merit of this method in identifying coherent structures, we compare the results with the well-known Q-criterion.