THE STABILITY OF AN INTERFACE BETWEEN VISCOUS FLUIDS SUBJECTED TO A HIGH-FREQUENCY MAGNETIC-FIELD AND CONSEQUENCES FOR ELECTROMAGNETIC CASTING

The stability of an interface between inviscid fluids subjected to a h igh-frequency magnetic field has been examined previously by Garnier & Moreau (1983). The present paper extends that study to include the vi scosity of both fluids in order to estimate the damping rates of the p erturbations. Furthermore, Garnier & Moreau made an assumption that th e frequency of oscillation of the interface could be neglected compare d to the frequency of the applied field; they concluded that the appli ed field was not destabilizing. That (apparently reasonable) assumptio n has been lifted in the present work and the consequence is that the magnetic field is seen to lead to instability over a significant range of wavelengths. Application of this analysis to the electromagnetic c asting of aluminium is discussed.