The motion of the axis of a large-scale vortex flow of liquid metal in a disk cell caused by low magnitude azimuthal electromagnetic force with non-linear radial distribution

Abstract

Laminar flow of liquid metal caused by axisymmetric electromagnetic force with non-linear radial distribution is studied numerically. Electromagnetic force is defined by the vector product of current density and orthogonal magnetic induction. Non-linear radial force distribution with maximum occurs when electric current is applied to the central region of the cell and discharged through the periphery while magnetic field is created by Helmholtz coils with a diameter less than that of the cell. Numerical simulation was conducted in ANSYS Fluent. It has been discovered that, in a certain range of parameters, the axis of the rotating liquid-metal flow starts oscillatory motion relative to the center of the cell. This effect appears in the occurrence of secondary flows such as Görtler vortices, Ekman pumping, and Kelvin-Helmholtz instability. The boundary between the regions of the absence and occurrence of a large-scale vortex oscillation has been found in the space of geometric and force parameters.