Convective instability in a thermally stable air layer under a gradient magnetic field

摘要

Two-dimensional numerical computations were carried out in order to examine the influence of magnetizing force for a thermally stable air layer in a vertical cylindrical container under a gradient magnetic field. The average Nusselt number increased with increase of magnetic strength when the circular electric coil was placed at the hot plate or the central height of a container. On the other hand, when the circular electric coil was placed at the cold plate, the average Nusselt number was about unity. For three different positions of the circular electric coil, the mechanism of the occurrence of the magnetizing convection was clarified by visualizing temperature and velocity fields in the transition to the steady state.