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

In order to carry out numerical simulations taking into account detailed chemistry 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 manifold. We use in practice manifolds with two chemical dimensions in this work. Validations are performed for a homogeneous reaction system and one-dimensional laminar premixed CO/H-2/air flames. Computing times are reduced by a factor of 20 compared to the detailed chemistry case. We also check two different 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 comparison with corresponding detailed chemistry results is shown, proving that this reduction technique is appropriate for the investigation of turbulent combustion problems. The CPU time is reduced by a factor of 2.6 when using the ILDM method.