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Quasi-static magnetohydrodynamic turbulence at high Reynolds number
| Content Provider | Semantic Scholar |
|---|---|
| Author | Favier, By V. Godeferd, Fabien S. Cambon, Claude Delache, Alexandre Bos, Wouter J. T. |
| Copyright Year | 2011 |
| Abstract | We analyse the anisotropy of homogeneous turbulence in an electrically conducting fluid submitted to a uniform magnetic field, for low magnetic Reynolds number, in the quasi-static approximation. We interpret contradictory earlier predictions between linearized theory and simulations: in the linear limit, the kinetic energy of transverse velocity components, normal to the magnetic field, decays faster than the kinetic energy of the axial component, along the magnetic field (Moffatt, J. Fluid Mech., vol. 28, 1967, p. 571); whereas many numerical studies predict a final state characterized by dominant energy of transverse velocity components. We investigate the corresponding nonlinear phenomenon using direct numerical simulation (DNS) of freely decaying turbulence, and a two-point statistical spectral closure based on the eddy-damped quasi-normal Markovian (EDQNM) model. The transition from the three-dimensional turbulent flow to a ‘two-and-a-half-dimensional’ flow (Montgomery & Turner, Phys. Fluids, vol. 25, 1982, p. 345) is a result of the combined effects of short-time linear Joule dissipation and longer time nonlinear creation of polarization anisotropy. It is this combination of linear and nonlinear effects which explains the disagreement between predictions from linearized theory and results from numerical simulations. The transition is characterized by the elongation of turbulent structures along the applied magnetic field, and by the strong anisotropy of directional twopoint correlation spectra, in agreement with experimental evidence. Inertial equatorial transfers in both DNS and the model are presented to describe in detail the most important equilibrium dynamics. Spectral scalings are maintained in high-Reynoldsnumber turbulence attainable only with the EDQNM model, which also provides simplified modelling of the asymptotic state of quasi-static magnetohydrodynamic (MHD) turbulence. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://hal.archives-ouvertes.fr/hal-00647794/document |
| Alternate Webpage(s) | http://hal.inria.fr/docs/00/64/77/94/PDF/Favier_JFM_2011.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Anisotropy Approximation CPU power dissipation Closure Computer simulation Direct numerical simulation Electricity Joule Kinetics Liquid substance Magnetic Fields Magnetic Resonance Imaging Montgomery modular multiplication Nonlinear system Numerical analysis Numerical integration Polarization (waves) Reynolds-averaged Navier–Stokes equations Stellar classification Transverse wave Turbulence Velocity (software development) Volume |
| Content Type | Text |
| Resource Type | Article |
