Energy dissipation rates in low-$\Re_m$ MHD turbulence with mean shear: Results for channel flow with spanwise field

TL;DR

This study investigates how a spanwise magnetic field influences energy dissipation in low-Reynolds-number MHD channel turbulence, revealing that Joule dissipation can surpass viscous dissipation in the bulk but remains small near the walls.

Contribution

It provides new insights into the spatial distribution of energy dissipation mechanisms in MHD turbulence with mean shear, based on direct and large eddy simulations.

Findings

Joule dissipation can exceed viscous dissipation in the bulk region.

Joule dissipation remains small in the near-wall turbulence-generating region.

Magnetic fields significantly alter energy dissipation profiles in channel flow.

Abstract

We examine the changes in kinetic energy dissipation of a turbulent channel flow caused by a spanwise magnetic field. The numerical study is based on our simulation data from [Krasnov, Zikanov, Schumacher, Boeck, Phys. Fluids 20, 095105 (2008)] obtained by direct and large eddy simulations. We find that the Joule dissipation can exceed the viscous dissipation in the weakly dissipative bulk region, but remains comparatively small in the turbulence-generating near-wall region.