NUMERICAL-SIMULATION OF SECONDARY FLOWS IN CHANNELS DRIVEN BY APPLIEDLORENTZ FORCES

The effect of applied magnetohydrodynamic (Lorentz) forces on the flow fields in saltwater plane channel flow has been investigated by perfor ming large-scale computer simulations. Direct numerical simulations of three-dimensional. time-dependent secondary how of an electroconducti ng fluid driven by Lorentz forces caused by applied electromagnetic fi elds have been performed, The computational model consists of a two-di mensional doubly periodic configuration of magnet and electrode microt iles flush-mounted on the lower surface of the channel. The resulting flowfields for low Reynolds number simulations reveal that the applied downward Lorentz force formed over the area between the magnet/electr ode pairs causes the velocity perturbations to be confined to a very t hin layer in the wall-normal direction, Thus, the design objective of localizing the Lorentz force close to the Hall is achieved. Lateral co mponents of the Lorentz force also contribute significantly to the for mation of the secondary vortical flowfield, Simulations were also carr ied out with a pulsatile Lorentz Force, The results show that this tec hnique is a viable method of perturbing the how while reducing the pow er consumption and corrosion of the microtiles.