Direct numerical simulation of turbulent premixed flames using intrinsic low-dimensional manifolds

In order to carry out numerical simulations taking into account detailed ch emistry effects with a realistic computing cost, we describe in this work a new method to generate intrinsic low-dimensional manifold (ILDM) databases . This method is based on a continuation procedure to determine the manifol d. We use in practice manifolds with two chemical dimensions in this work. Validations are performed for a homogeneous reaction system and one-dimensi onal laminar premixed CO/H-2/air flames. Computing times are reduced by a f actor of 20 compared to the detailed chemistry case. We also check two diff erent projection methods used to project the diffusion term on the manifold . We observe that a simple perpendicular projection is appropriate for our configuration. The final part of this paper describes the implementation of the ILDM method in the direct numerical simulation code parcomb. A compari son with corresponding detailed chemistry results is shown, proving that th is reduction technique is appropriate for the investigation of turbulent co mbustion problems. The CPU time is reduced by a factor of 2.6 when using th e ILDM method.