{ "id": "1106.4157", "version": "v1", "published": "2011-06-21T09:58:09.000Z", "updated": "2011-06-21T09:58:09.000Z", "title": "Low-dimensional model of turbulent Rayleigh-Benard convection in a Cartesian cell with square domain", "authors": [ "Jorge Bailon-Cuba", "Joerg Schumacher" ], "comment": "23 pages, 18 Postscript figures, Figures 6,7,8,9,17,18 in reduced quality", "journal": "Phys. Fluids 23 (2011) 077101", "doi": "10.1063/1.3610395", "categories": [ "physics.flu-dyn", "nlin.CD" ], "abstract": "A low-dimensional model (LDM) for turbulent Rayleigh-Benard convection in a Cartesian cell with square domain, based on the Galerkin projection of the Boussinesq equations onto a finite set of empirical eigenfunctions, is presented. The empirical eigenfunctions are obtained from a joint Proper Orthogonal Decomposition (POD) of the velocity and temperature fields using the Snapshot Method on the basis of a direct numerical simulation (DNS). The resulting LDM is a quadratic inhomogeneous system of coupled ordinary differential equations which we use to describe the long-time temporal evolution of the large-scale mode amplitudes for a Rayleigh number of 1e5 and a Prandtl number of 0.7. The truncation to a finite number of degrees of freedom, that does not exceed a number of 310 for the present, requires the additional implementation of an eddy viscosity-diffusivity to capture the missing dissipation of the small-scale modes. The magnitude of this additional dissipation mechanism is determined by requiring statistical stationarity and a total dissipation that corresponds with the original DNS data. We compare the performance of two models, a constant so-called Heisenberg viscosity--diffusivity and a mode-dependent or modal one. The latter viscosity--diffusivity model turns out to reproduce the large-scale properties of the turbulent convection qualitatively well, even for a model with only a few hundred POD modes.", "revisions": [ { "version": "v1", "updated": "2011-06-21T09:58:09.000Z" } ], "analyses": { "subjects": [ "47.27.te", "02.60.Cb", "47.11.-j", "47.20.Bp", "47.27.ek", "47.27.tb" ], "keywords": [ "turbulent rayleigh-benard convection", "cartesian cell", "low-dimensional model", "square domain", "joint proper orthogonal decomposition" ], "tags": [ "journal article" ], "publication": { "publisher": "AIP", "journal": "Physics of Fluids", "year": 2011, "month": "Jul", "volume": 23, "number": 7, "pages": 7101 }, "note": { "typesetting": "TeX", "pages": 23, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2011PhFl...23g7101B" } } }