1996 Volume 82 Issue 12 Pages 1047-1052
A new process for wave generation on the free surface of a molten metal is proposed where an intermittent alternating magnetic field with the stepwise change of amplitude is adopted to induce the time variation of magnetic pressure generating a wave motion.
Based on a linear small-amplitude wave theory, a mathematical model has been developed, which describes the wave motion as a function of operating variables such as intermittent frequency, amplitude of magnetic pressure and vessel size. The function is indicated as combination of a free vibration determined by a vessel size and a forced vibration, in which the amplitude of the latter is in proportion to the magnetic pressure difference at the maximum and the minimum magnetic fields.
To confirm the validity of the mathematical model, an experiment with liquid gallium was performed. It was found from FFT analysis of the wave motion measured by a laser level sensor that the frequencies of the wave motion are composed of an intermittent frequency of the magnetic pressure and the intrinsic frequencies of a vessel. A resonance phenomenon was observed when the intermittent frequency coincided with the intrinsic frequency. Except the resonance case, the amplitude of the wave motion was in proportion to the amplitude of the magnetic pressure difference. These observed results are well predicted by the mathematical model.
