New Class of Hybrid Schemes Based on Large Eddy Simulation and Low- Dimensional Stochastic Models

摘要

A hybrid approach for large-eddy simulations (LES) of turbulent combustion with the One-Dimensional Turbulence (ODT) model is developed. The need for a structure-based approach can address some of the key challenges arising in the prediction of non-linear physics on the sub-grid scale. The implementation involves hybrid solutions of 3-D LES with 1-D solutions based on the ODT, with ODT elements embedded within the LES computational domain. The solutions require the coupling of LES and ODT, as well as the coupling of the different ODT 'processes'. The proposed methodology represents a fundamentally new framework to address sub-grid scale physics where statistical information cannot be represented in LES-resolved physics or cannot be assumed a priori. Numerical implementation issues are addressed, including a novel implementation of filtered advection for scalars and momentum. Validation studies based on the non-homogeneous auto-ignition show that the proposed framework and specific implementations yield excellent predictions of the physics.