Vortex patterns of a magnetic obstacle wake

The vortex structure of an electrically conducting liquid flowing past a localized magnetic obstacle wake is simulated. When the field strength exceeds a critical value, a localized Lorentz breaking force produces a virtual body filled with a pair of counter-rotating vortices. It is shown that a pair of tail vortices forms behind the body vortex pair to produce a four-vortex pattern if the field strength exceeds a second critical value. Before and after separation of the tail vortex from the body vortex, new vortices of two types emerge between them to produce six-vortex patterns. Figs 4, Refs 24.