Stabilization of a molten-metal/coolant-gas interface by electromagnetic fields

Experiments were conducted in which nitrogen gas flowed at a uniform velocity in a rectangular channel over the surface of a shallow horizontal dish containing liquid tin in the presence of a 10 kHz magnetic field above the tin surface. The threshold gas velocity for wave formation was determined with the magnetic field oriented parallel or perpendicular to the gas flow. In both orientations, the threshold velocity increased as magnetic-field strength increased at a rate much larger than predicted by linear stability theories, and the enhanced wave suppression was attributed to the influence of electromagnetic stirring.