Viscosimetry of a non-Newtonian interface: The interesting role of MHD

K. Patouillet^{1, 2} - L. Davoust¹ - O. Doche¹

¹ University Grenoble Alpes, CNRS, Grenoble INP, SIMAP, F-38000 Grenoble, France
² Linamar Light Metal Casting, Techcenter 3 rue de Nogent, 60290 Laigneville, France

Abstract
In this paper, a theoretical background is introduced to justify the interest of magnetohydrodynamics to surface viscosimetry of electrically conducting fluids, such as liquid or molten metals covered with a thin oxide layer. The system under consideration is based on an annular shallow-channel layout exposed to a uniform magnetic field. Due to the well-known 2D tendency of low-Rm magnetohydrodynamics, the vertically applied magnetic field allows to monitor the coupling between surface rheology and supporting flow. Thus, it is shown that a non-Newtonian behavior can be easily highlighted by adjusting the intensity of the magnetic field, whatever the mechanical behavior of the interface: shear-thinning or shear-thickening. Figs 4, Refs 17.