A Multilevel Algorithm for Large-Eddy Simulation of Turbulent Compressible Flows

A multilevel method for large-eddy simulation of turbulent compressible flows is proposed. The method relies on the splitting of the turbulent flowfield into several frequency bands in space and time, each band being associated to a specific computational grid in physical space. This allows to take into account in a deterministic way the information contained on finer grids. A subgrid model adapted to such a decomposition—based on a generalization of the Germanoʹs identity to multilevel decomposition—is also introduced. The approach is validated by several multilevel simulations in a subsonic plane channel flow configuration for a low and a high value of the Reynolds number, while reductions of the CPU times up to 80% are obtained.