09.05.2012, 14:00 Uhr
Formulation and Application of a Sparse-Modes Method for Turbulence Simulation

Abstract
Subgrid closure of coarse-grained simulations of turbulent flows is challenging near walls and for multi-physics applications such as reacting flows. The sparse-modes approach can avoid coarse-grained advancement while reducing cost relative to direct numerical simulation. In the formulation described here, the smallest scales of motion are resolved on three arrays of sub-domains, such that each array fills the flow volume and provides full resolution in one coordinate direction. Within each sub-domain, a stochastic model termed One-Dimensional Turbulence (ODT) simulates turbulent flow advancement in the resolved direction. An additional advection process couples the sub-domains so as to capture large-scale 3D motion without requiring advancement of filtered flow properties. This formulation, termed ODTLES, has been used to simulate decaying homogeneous turbulence and various wall-bounded flows. The ability of this sparse-modes type of approach to capture 3D large-scale features while affordably resolving the wall-normal structure of near-wall flow is demonstrated.