Large eddy simulation of turbulence-chemistry interactions in reacting flows

Application of the Large Eddy Simulation (LES) technique provides the formal ability to treat the wide range of multidimensional time and length scales that exist in turbulent reacting flows in a computationally feasible manner. The large energetic-scales are resolved directly. The small ''subgrid-scales'' are modeled. This allows simulation of the complex multiple-time multiple-length scale coupling between processes in a time-accurate manner. Treating the full range of scales is a critical requirement since turbulent processes are inherently coupled through a cascade of nonlinear interactions. This paper provides a perspective on LES and its application to turbulent combustion. In particular, the combination of LES, high-performance massively-parallel computing, and advanced experimental capabilities in combustion science offer unprecedented opportunities for synergistic high- fidelity investigations. Information from well-defined benchmark flames, using a combination of stateof- the-art experiments and detailed simulations that match the experimental conditions, present new opportunities to understand the central physics of turbulence-chemistry interactions. Understanding these fundamental physical processes, and developing advanced simulation capabilities that efficiently and accurately describe them, are crucial requirements for the development of next generation combustion systems. Results are shown that demonstrate the progression toward more complex systems, with emphasis placed on the fundamental issues of turbulence-chemistry interactions.