Rich vortex dynamic of liquid metal in T-shaped cylindrical cell under counter-rotating magnetic field action

Flow regimes arising in a T-shaped cell filled with liquid metal under the action of oppositely directed azimuthal electromagnetic forces were investigated. A flow regime map was produced, and the key characteristics of each observed flow type were described. Among the identified flow regimes, funnel rotation, jet flows, tornado-like vortex and their combinations can be distinguished. A flow topologically similar to a magnetohydrodynamic tornado, as well as vertical jet streams, were obtained for the first time without through-flow pumping, using fundamentally planar forces. The study includes experimental observation of flow structures on the free surface of a liquid metal and on the main cell axis, as well as three-dimensional numerical modelling to reconstruct the flow structure in the bulk. A low-melting-point gallium alloy was used as the working fluid. Surface velocity measurements were performed using particle image velocimetry with bubble tracers. Numerical simulations were conducted in a simplified formulation, neglecting free surface deformation.