Lagrangian-averaged model for magnetohydrodynamic turbulence and the absence of bottlenecks
We demonstrate that, for the case of quasiequipartition between the velocity and the magnetic field, the Lagrangian-averaged magnetohydrodynamics (LAMHD) α model reproduces well both the large-scale and the small-scale properties of turbulent flows; in particular, it displays no increased (superfilt...
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2009
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15393755_v80_n1_p_PietarilaGraham http://hdl.handle.net/20.500.12110/paper_15393755_v80_n1_p_PietarilaGraham |
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paper:paper_15393755_v80_n1_p_PietarilaGraham2023-06-08T16:20:42Z Lagrangian-averaged model for magnetohydrodynamic turbulence and the absence of bottlenecks Mininni, Pablo Daniel Averaged models Bottleneck effects Degrees of freedom Energy spectra Internal degrees of freedom Lagrangian Magnetohydrodynamic turbulence N-waves Navier Stokes Neutral fluids Nonlocal Reduction factor Scale properties Spatial regions Spectral properties Subfilter scale Superfilters Computer simulation languages Energy transfer Filters (for fluids) Fluid dynamics Lagrange multipliers Lorentz force Magnetic fields Mechanics Reynolds number Spectroscopy Turbulent flow Magnetohydrodynamics We demonstrate that, for the case of quasiequipartition between the velocity and the magnetic field, the Lagrangian-averaged magnetohydrodynamics (LAMHD) α model reproduces well both the large-scale and the small-scale properties of turbulent flows; in particular, it displays no increased (superfilter) bottleneck effect with its ensuing enhanced energy spectrum at the onset of the subfilter scales. This is in contrast to the case of the neutral fluid in which the Lagrangian-averaged Navier-Stokes α model is somewhat limited in its applications because of the formation of spatial regions with no internal degrees of freedom and subsequent contamination of superfilter-scale spectral properties. We argue that, as the Lorentz force breaks the conservation of circulation and enables spectrally nonlocal energy transfer (associated with Alfvén waves), it is responsible for the absence of a viscous bottleneck in magnetohydrodynamics (MHD), as compared to the fluid case. As LAMHD preserves Alfvén waves and the circulation properties of MHD, there is also no (superfilter) bottleneck found in LAMHD, making this method capable of large reductions in required numerical degrees of freedom; specifically, we find a reduction factor of 200 when compared to a direct numerical simulation on a large grid of 15363 points at the same Reynolds number. © 2009 The American Physical Society. Fil:Mininni, P.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2009 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15393755_v80_n1_p_PietarilaGraham http://hdl.handle.net/20.500.12110/paper_15393755_v80_n1_p_PietarilaGraham |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Averaged models Bottleneck effects Degrees of freedom Energy spectra Internal degrees of freedom Lagrangian Magnetohydrodynamic turbulence N-waves Navier Stokes Neutral fluids Nonlocal Reduction factor Scale properties Spatial regions Spectral properties Subfilter scale Superfilters Computer simulation languages Energy transfer Filters (for fluids) Fluid dynamics Lagrange multipliers Lorentz force Magnetic fields Mechanics Reynolds number Spectroscopy Turbulent flow Magnetohydrodynamics |
| spellingShingle |
Averaged models Bottleneck effects Degrees of freedom Energy spectra Internal degrees of freedom Lagrangian Magnetohydrodynamic turbulence N-waves Navier Stokes Neutral fluids Nonlocal Reduction factor Scale properties Spatial regions Spectral properties Subfilter scale Superfilters Computer simulation languages Energy transfer Filters (for fluids) Fluid dynamics Lagrange multipliers Lorentz force Magnetic fields Mechanics Reynolds number Spectroscopy Turbulent flow Magnetohydrodynamics Mininni, Pablo Daniel Lagrangian-averaged model for magnetohydrodynamic turbulence and the absence of bottlenecks |
| topic_facet |
Averaged models Bottleneck effects Degrees of freedom Energy spectra Internal degrees of freedom Lagrangian Magnetohydrodynamic turbulence N-waves Navier Stokes Neutral fluids Nonlocal Reduction factor Scale properties Spatial regions Spectral properties Subfilter scale Superfilters Computer simulation languages Energy transfer Filters (for fluids) Fluid dynamics Lagrange multipliers Lorentz force Magnetic fields Mechanics Reynolds number Spectroscopy Turbulent flow Magnetohydrodynamics |
| description |
We demonstrate that, for the case of quasiequipartition between the velocity and the magnetic field, the Lagrangian-averaged magnetohydrodynamics (LAMHD) α model reproduces well both the large-scale and the small-scale properties of turbulent flows; in particular, it displays no increased (superfilter) bottleneck effect with its ensuing enhanced energy spectrum at the onset of the subfilter scales. This is in contrast to the case of the neutral fluid in which the Lagrangian-averaged Navier-Stokes α model is somewhat limited in its applications because of the formation of spatial regions with no internal degrees of freedom and subsequent contamination of superfilter-scale spectral properties. We argue that, as the Lorentz force breaks the conservation of circulation and enables spectrally nonlocal energy transfer (associated with Alfvén waves), it is responsible for the absence of a viscous bottleneck in magnetohydrodynamics (MHD), as compared to the fluid case. As LAMHD preserves Alfvén waves and the circulation properties of MHD, there is also no (superfilter) bottleneck found in LAMHD, making this method capable of large reductions in required numerical degrees of freedom; specifically, we find a reduction factor of 200 when compared to a direct numerical simulation on a large grid of 15363 points at the same Reynolds number. © 2009 The American Physical Society. |
| author |
Mininni, Pablo Daniel |
| author_facet |
Mininni, Pablo Daniel |
| author_sort |
Mininni, Pablo Daniel |
| title |
Lagrangian-averaged model for magnetohydrodynamic turbulence and the absence of bottlenecks |
| title_short |
Lagrangian-averaged model for magnetohydrodynamic turbulence and the absence of bottlenecks |
| title_full |
Lagrangian-averaged model for magnetohydrodynamic turbulence and the absence of bottlenecks |
| title_fullStr |
Lagrangian-averaged model for magnetohydrodynamic turbulence and the absence of bottlenecks |
| title_full_unstemmed |
Lagrangian-averaged model for magnetohydrodynamic turbulence and the absence of bottlenecks |
| title_sort |
lagrangian-averaged model for magnetohydrodynamic turbulence and the absence of bottlenecks |
| publishDate |
2009 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15393755_v80_n1_p_PietarilaGraham http://hdl.handle.net/20.500.12110/paper_15393755_v80_n1_p_PietarilaGraham |
| work_keys_str_mv |
AT mininnipablodaniel lagrangianaveragedmodelformagnetohydrodynamicturbulenceandtheabsenceofbottlenecks |
| _version_ |
1768544290405875712 |