Magnetoconvection transient dynamics by numerical simulation

Sébastien Renaudière de Vaux (1, 2) , Rémi Zamansky (1) , Wladimir Bergez (1) , Philippe Tordjeman (1) , Jean-François Haquet (3)

1 IMFT - Institut de mécanique des fluides de Toulouse
2 CEA - Commissariat à l'énergie atomique et aux énergies alternatives
3 LMPA - Laboratoire des Matériaux et Procédés Actifs

We investigate the transient and stationary buoyant motion of the Rayleigh-Bénard instability when the fluid layer is subjected to a vertical, steady magnetic field. For Rayleigh number, Ra, in the range 10^3-10^6, and Hartmann number, Ha, between 0 and 100, we performed three-dimensional direct numerical simulations. To predict the growth rate and the wavelength of the initial regime observed with the numerical simulations, we developed the linear stability analysis beyond marginal stability for this problem. We analyzed the pattern of the flow from linear to nonlinear regime. We observe the evolution of steady state patterns depending on Ra/Ha2 and Ha. In addition, in the nonlinear regime, the averaged kinetic energy is found to depend on Ra and to be independent of Ha in the studied range.

Mots clés: Magnetoconvection; Rayleigh Bénard instability; Numerical simulation

Domaines: Mécanique des fluides [physics.class-ph]

Sébastien Renaudière de Vaux, Rémi Zamansky, Wladimir Bergez, Philippe Tordjeman, Jean-François Haquet. Magnetoconvection transient dynamics by numerical simulation. European Physical Journal E: Soft matter and biological physics, 2017, 40 (1), pp.13. ⟨10.1140/epje/i2017-11499-2⟩. ⟨hal-01643599⟩