Eulerian Time-Domain Filtering for Spatial Large-Eddy Simulation

Abstract

An approach to large-eddy simulation is developed whose subgrid-scale model incorporates Eulerian time-domain filtering, in contrast to conventional approaches that exploit spatial filtering. For applications to large-eddy simulation, time-domain filters enjoy certain advantages relative to spatial filters. Among these, they more naturally commute with differentiation operators than do spatial filters, and there is typically wide separation between numerical truncation error and the dissipation of the subgrid-scale model. Eulerian time-domain filtering is most appropriate for flows whose large coherent structures convect approximately at a common characteristic velocity. Such flows include jets, mixing layers, and wakes. The method is demonstrated in the large-eddy simulation of a heated, subsonic, axisymmetric jet, and results are compared with those obtained from well-resolved direct numerical simulation