Near-wall MHD turbulence: investigation of a spanwise magnet array configuration

A. Capogna - O. Doche - L. Davoust

SIMaP laboratory, EPM group, 1130 rue de la Piscine, Domaine Universitaire, 38402 Saint-Martin d'Héres, France

Abstract
Direct numerical simulations of turbulent channel flows subjected to non-uniform magnetic fields are presented. The magnetic fields are delivered by spanwise distributions of permanent magnets located on the top and bottom walls of the channel. This configuration generates mainly magnetic field components perpendicular and transverse to the wall. Three different values of magnet thickness are considered. For each calculation, the average magnetic intensity imposed in a selective part (\it{i.e.} the turbulent inner layer) of the channel is kept constant so that the only parameter studied is the shape of the magnetic field. We show that larger magnets tend to create more homogeneous magnetic distributions in the near-wall region and lead to a better reduction in turbulent activity in this region. Figs 10, Refs 4.