On the effect of rotation on magnetohydrodynamic turbulence at high magnetic Reynolds number

• Published in: arXiv.org 2011-03
• Main Authors: Favier, Benjamin F N, Godeferd, Fabien S, Cambon, Claude
• Format: Article
• Language: English
• Subjects: Computational fluid dynamics; Computer simulation; Conducting fluids; Coriolis force; Earth core; Energy transfer; Fluid flow; Geophysics; Incompressible flow; Interaction parameters; Magnetic fields; Magnetic variations; Magnetohydrodynamic turbulence; Magnetohydrodynamics; Misalignment; Reynolds number; Rotating fluids; Rotation
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1103.6236

This article is focused on the dynamics of a rotating electrically conducting fluid in a turbulent state. As inside the Earth's core or in various industrial processes, a flow is altered by the presence of both background rotation and a large scale magnetic field. In this context, we present a set of 3D direct numerical simulations of incompressible decaying turbulence. We focus on parameters similar to the ones encountered in geophysical and astrophysical flows, so that the Rossby number is small, the interaction parameter is large, but the Elsasser number, defining the ratio between Coriolis and Lorentz forces, is about unity. These simulations allow to quantify the effect of rotation and thus inertial waves on the growth of magnetic fluctuations due to Alfvén waves. Rotation prevents the occurrence of equipartition between kinetic and magnetic energies, with a reduction of magnetic energy at decreasing Elsasser number {\Lambda}. It also causes a decrease of energy transfer mediated by cubic correlations. In terms of flow structure, a decrease of {\Lambda} corresponds to an increase in the misalignment of velocity and magnetic field.