Natural Convection in Liquid Metals Subjected to Alternating Magnetic Fields

摘要

This present study involves numerical simulation of Navier-Stakes, energy and hydromagnetic equations in order to analyse two-dimensional natural convection of liquid metals subjected to variable strength and variable frequency alternating magnetic fields. The spatio-temporal study yields steady to oscillatory fluid flow patterns on variation of intensity and frequency of applied alternating magnetic fields, with increasing Rayleigh numbers. It has been found that the strength of the magnetic field governs the amplitudes of the velocities whilst the frequency controls both the amplitude and the spatial configuration of the flow, for a fixed Rayleigh number (Ra). Increase in Rayleigh number brings about more rigorous mixing for constant strength and frequencies of the alternating magnetic fields. Due to the skin effect, which is more predominant at higher frequencies, electromagnetic forces create strong velocity shears that are responsible for generation of secondary rolls at the corners of the enclosure and temporal variation of dynamical variables.