Large eddy simulation of turbulent reacting flows using cartesian grid and boundary corrections

A high order Cartesian grid method is developed and applied to large eddy simulations (LES) of isothermal and reactive turbulent flows. Cartesian grid methods are potentially the most suitable numerical methods for LES because of its economical storage requirement, less computational effort per computational cell, fast numerical convergence and feasibility for constructing higher order finite difference schemes. An uniform Cartesian grid with high order interpolations is employed to handle the curved walls. The small cell limitation on the time steps is remedied by using an implicit scheme based on an efficient Multi-Grid (MG) acceleration method and local grid refinement technique. Application of the numerical method to LES of isothermal and reactive flows shows that the low order piecewise constant wall approximation affects the energy flux in the cascade near the walls. This affects the overall turbulence level and even affects the mean of the whole flow field. Numerical experiments show that 3rd order Lagrangian interpolation near the walls results in a stable LES, while higher order interpolations may trigger numerical instability