Magnetic field advection in a rotating magnetic field driven flow induced by a non-ideal inductor

Abstract

The limits of the axisymmetric ideal inductor approach and the low magnetic Reynolds number (Rem) approach are demonstrated for the case study of a flow driven by a rotating magnetic field induced by an explicit-pole non-ideal inductor. These effects are studied for an intermediate range of the magnetic Reynolds number 0.1 ≤ Rem ≤ 1. It is shown that phenomena that do not exist under the ideal inductor approach change the distribution of the electromagnetic body force (EMBF) from axial symmetry to rotational symmetry. However, it is found that the magnetic field advection (MFA), which is neglected under the low Rem approach, induces body force that changes the distribution of the EMBF so that it effectively becomes closer to being axisymmetric. Therefore, it is suggested that the ideal inductor approach should not be applied in low Rem applications; this approach can be applied in high Rem applications. It is also found that the effect of MFA on the averaged velocity field is negligible for higher values of Rem than traditionally assumed, but MFA has a significant effect in reducing the turbulent kinetic energy. The reduction is found to be a result of the MFA-induced EMBF reducing the turbulence production.