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The performance of different dynamic gradient-diffusion type sub-grid models is evaluated in large-eddy simulations (LES) of magnetohydrodynamic (MHD) turbulence with a maximum of 64(3) collocation points. The reference data stems from high-resolution direct numerical simulations of decaying and forced MHD turbulence with up to 512(3) spectral modes. Comparisons between LES' and the grid filtered reference systems are carried out regarding the temporal evolution of the global quantities kinetic and magnetic energy, cross helicity, magnetic helicity, and the spectra of energy and energy flux. The influence of the sub-grid models on the statistical properties of the simulated flows is also examined. Apart from unconditionally dissipative models, direct divergence modeling and the effects of additional explicit filtering in combination with a tensor-diffusivity term are considered. A new genuine MHD sub-grid model, based on the cross-helicity invariant, is presented and observed to perform outstandingly well.

Additional information

Authors: MÜLLER W-C, Centre for Interdisciplinary Plasma Science, Max-Planck-Institut für Plasmaphysik, EURATOM Association, Garching (DE);CARATI D, Euratom�Belgian State Association, Physique statistique et des plasmas, Université Libre de Bruxelles, Brussels (BE);MULLER W-C, Centre for Interdisciplinary Plasma Science, Max-Planck-Institut fur Plasmaphysik, EURATOM Association, Garching (DE)
Bibliographic Reference: An article published in: Physics of Plasmas - March 2002 - Volume 9, Issue 3, pp. 824-834
Record Number: 200214635 / Last updated on: 2002-04-19
Original language: en
Available languages: en