The formation of a magnetically driven tornado-like vortex

A tornado-like vortex is driven by magnetic body forces. A continuously applied rotating magnetic field provides the source of the angular momentum. A pulse of about one order of magnitude stronger travelling magnetic field drives a converging flow that temporarily focuses this angular momentum towards the axis of the container. A highly concentrated vortex forms that produces a funnel-shaped surface depression. The considered transient flow may find a practical application for the purpose of contact-less mixing of floating particles into molten metal, for instance, during the production of oxide dispersion strengthened (ODS) alloys. We explore experimentally the duration, the depth and the conditions of formation of this funnel. Additionally, we measure the axial velocity and calculate the axisymmetric flow field of this transient vortex at a lower force magnitude.