Rotating magnetic dipole-driven flows in a conducting liquid cylinder.

Four configurations of a rotating magnetic dipole-driven turbulent flow in an electrically conducting liquid cylinder are considered by spectral direct numerical simulation. These configurations differ by parallel or perpendicular orientation of the dipole rotation vector with respect to the nearest surface of the cylinder or its axis. The rotating dipole generates electromagnetic force in a thin outer liquid layer facing it. A concentrated vortex is driven when the dipole rotation vector is perpendicular to the nearest surface. This vortex closely resembles the rotating disk-driven flow. When the dipole rotation vector is parallel to the nearest surface, then a distributed vortex occurs akin of the translating wall-driven cavity flow. The characteristic velocity is comparably little influenced by dipole orientation despite the electromagnetic force magnitude varying by a factor of three. Perpendicular orientation of the magnetic dipole rotation vector with respect to the cylinder's axis causes secondary corner eddies increasing the overall turbulent fluctuation. The simulations are supplemented by an experiment featuring a deep and narrow funnel-shaped quasi-stationary free surface deformation above a concentrated vortex. [ABSTRACT FROM AUTHOR]