GLOBAL AND LOCAL STABILITY OF MAGNETICALLY-LEVITATED DROPLETS

摘要

This paper presents a numerical study of the global stability of and the local linear and nonlinear magnetically-induced flow instability in a liquid droplet levitated in an alternating magnetic field. The analysis is based on the numerical solution of the full 3-D, time harmonic Maxwell equations using the combined finite element and boundary element method, with edge elements chosen to eliminate spurious nonphysical modes. The global stability, that is, the rigid body translational and rotational movement of the droplet from its equilibrium position, is studied by solving the linear and angular momentum equations with the electromagnetic source term. The linear and nonlinear flow stabilities of the magnetically-levitated droplet are studied based on the high-order finite difference solution of the Navier-Stokes equations with induced electromagnetic forces. Both linear and nonlinear phenomena are studied. The numerical results are compared with experimental observations.