The dynamic behaviour of magnet-magnetic fluid systems in alternating magnetic fields

S. Sudo¹ - M. Shinozaki¹ - H. Nishiyama²

¹ Faculty of Systems Science and Technology, Akita Prefectural University, Ebinokuchi 84-4, Tsuchiya, Yurihonjo 015-0055, Japan
² Institute of Fluid Science, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan

Abstract
This paper is concerned with the surface phenomena of magnetic fluid adsorbed on a small NdFeB permanent magnet subject to alternating magnetic fields. The dynamic behaviour of some magnet-magnetic fluid systems in alternating magnetic fields is studied with a digital high-speed video camera system. Magnetic fluid surface waves are observed in a wider range of input frequency from 10 Hz to 200 Hz. The frequency of magnetic fluid surface motion for most forms of external alternating field usually corresponds to the input frequency. Large-amplitude surface waves and drop ejection from a magnetic fluid surface occur in some systems at the natural frequency of the system. Figs 9, Refs 11.