Three-dimensional computation of convection of water at the center of a superconducting magnet

Abstract

Magnetothermal convection of water (diamagnetic) contained in a shallow, cylindrical vessel heated from below and cooled from above at the center of a superconducting magnet was numerically studied. Various flow patterns appeared under the influence of the magnetic body force. The flows induced by the magnetic force whose radial component at the vessel side wall was 5.0 times gravity became axisymmetric, and the direction of the flow was opposite to that of the buoyancy-driven thermal convection. When the radial component was as large as gravity, the breaking and recovery of the axisymmetric flow pattern were aperiodically repeated. When it was 0.1 or 0.5 times gravity, the flow showed a three-spoke pattern, breaking axisymmetry. It is discussed that the conditions to obtain such a spoke pattern experimentally are application of a relatively small magnetic field, use of a shallow vessel, and observation for sufficiently long time.