Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

Interfacial waves arising in a two-phase swirling flow driven by a low-frequency rotating
magnetic field (RMF) are studied. At low RMF frequencies, on the order of 1–10 Hz, the
oscillatory part of the induced Lorenz force becomes comparable to the time-averaged one
and cannot be neglected. In particular, when free surfaces or two-liquid stably stratified
systems are subject to a low-frequency RMF, induced pressure variations necessarily excite
free-surface/interfacial waves, which can improve mass transfer in different metallurgical
processes. In this paper we formulate a linear wave model and derive explicit analytical
solutions predicting RMF-driven wave patterns that closely resemble hyperbolic paraboloids.
These theoretical predictions are validated against experiments based on a nonintrusive
acoustic measurement technique, which measures liquid-liquid interface elevations in a
two-phase KOH-GaInSn stably stratified system. A good quantitative agreement is found
for nonresonant wave responses in the vicinity of the fundamental resonance frequency.
The experiments reveal the additional excitation of several higher harmonics superimposing
the fundamental wave oscillation, which are visible even in the linear wave regime.