title: Instability of the perfect subgrid model in implicit-filtering large eddy simulation of geostrophic turbulence.
abstract: We demonstrate, in the context of implicit-filtering large eddy simulations (LESs) of geostrophic turbulence, that while the attractor of a well-resolved statistically stationary turbulent flow can be reached in a coarsely resolved LES that is forced by the subgrid scale (SGS) terms diagnosed from the well-resolved computation, the attractor is generically unstable: the coarsely resolved LES system forced by the diagnosed SGS eddy terms has multiple attractors. This points to the importance of interpreting the diagnosed SGS forcing terms in a well-resolved computation or experiment from a combined physical-numerical point of view rather than from a purely physical point of view.
authors.affiliation: LANL, Los Alamos, New Mexico 87545, USA. balu@lanl.gov
authors.forename: B T
authors.initials: BT
authors.lastname: Nadiga
authors.forename: D
authors.initials: D
authors.lastname: Livescu