Nonlinear oscillations of molten silicon drops in electromagnetic levitator

Nonlinear oscillations of molten silicon drops in an electromagnetic levita tor under microgravity are numerically investigated. The electromagnetic fi eld and the magnetic pressure on the drop surface are calculated by the sur face integral method assuming that the skin depth is much smaller than the drop radius. The Galerkin finite element method in combination with the Lag rangian technique is used to analyze the moderate-amplitude axisymmetric os cillations of the silicon drops on which the magnetic pressure acts. The ef fect of the electric current ratio of the heating coils to the levitation c oils on the frequency of the oscillations is evaluated for molten silicon d rops released from either an initially prolate spheroid configuration or fo ur-lobed spherical harmonic configuration. The numerical results show that, in the former case, the frequency decreases with the current ratio. Also, for the latter, the dynamics of the second mode becomes dominant as the cur rent ratio increases, because the inward magnetic pressure from the heating coil increases.