Abstract
A study of the effect of an externally imposed magnetic field on the axisymmetry-breaking instability of an axisymmetric convective flow, associated with crystal growth from bulk of melt, is presented. Convection in a vertical cylinder with a parabolic temperature profile on the sidewall is considered as a representative model. A parametric study of the dependence of the critical Grashof number Grcr on the Hartmann number Ha for fixed values of the Prandtl number (Pr = 0.015) and the aspect ratio of the cylinder (A = height/radius = 1,2 and 3) is carried out. The stability diagram Grcr(Ha) corresponding to the axisymmetric - three-dimensional transition for increasing values of the axial magnetic field is obtained. The calculations are done using the spectral Galerkin method allowing an effective and accurate three-dimensional stability analysis. It is shown that at relatively small values of Ha the axisymmetric flow tends to be oscillatory unstable. After the magnitude of the magnetic field (Ha) exceeds a certain value the instability switches to a steady bifurcation caused by the Rayleigh-Bénard mechanism.
Original language | English |
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Pages (from-to) | 63-72 |
Number of pages | 10 |
Journal | Journal of Crystal Growth |
Volume | 230 |
Issue number | 1-2 |
DOIs | |
State | Published - Aug 2001 |
Externally published | Yes |
Keywords
- A1. Computer simulation
- A1. Convection
- A1. Heat transfer
- A1. Magnetic fields
- A2. Bridgman technique