The effect of subfilter-scale physics on regularization models

• Autores: Pietarila Graham, J.; Holm, D.D.; Mininni, P.; Pouquet, A.
• Año de publicación: 2011
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: J Sci Comput 2011;49(1):21-34
• Materia: Alpha models; Intermittency; LES; MHD; Subgrid-scale processes; Alpha model; Current sheets; Energy spectra; High Reynolds number; Intermittency; LES; Navier Stokes; Nonlocal; Regularization models; Rigid body; Small scale; Subfilter scale; Subgrid scale; Three models; Filters (for fluids); Lagrange multipliers; Local area networks; Lorentz force; Navier Stokes equations; Reynolds number; Rigid structures; Spectroscopy; Magnetohydrodynamics
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

The subfilter-scale (SFS) physics of regularization models are investigated to understand the regularizations' performance as SFS models. Suppression of spectrally local SFS interactions and conservation of small-scale circulation in the Lagrangian-averaged Navier-Stokes α-model (LANS-α) is found to lead to the formation of rigid bodies. These contaminate the superfilter-scale energy spectrum with a scaling that approaches k +1 as the SFS spectra is resolved. The Clark-α and Leray-α models, truncations of LANS-α, do not conserve small-scale circulation and do not develop rigid bodies. LANS-α, however, is closest to Navier-Stokes in intermittency properties. All three models are found to be stable at high Reynolds number. Differences between L 2 and H 1 norm models are clarified. For magnetohydrodynamics (MHD), the presence of the Lorentz force as a source (or sink) for circulation and as a facilitator of both spectrally nonlocal large to small scale interactions as well as local SFS interactions prevents the formation of rigid bodies in Lagrangian-averaged MHD (LAMHD-α). LAMHD-α performs well as a predictor of superfilter-scale energy spectra and of intermittent current sheets at high Reynolds numbers. It may prove generally applicable as a MHD-LES. © 2010 Springer Science+Business Media, LLC.
Fil:Mininni, P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.