Instabilities and transition in magnetohydrodynamic flows in ducts with electrically conducting walls.

This Letter presents a numerical study of a magnetohydrodynamic flow in a square duct with electrically conducting walls subject to a uniform, transverse magnetic field. Two regimes of instability and transition of Hunt's jets at the walls parallel to the magnetic field have been identified. The first one occurs for relatively low values of the Reynolds number Re and is associated with weak, periodic, counterrotating vortices discovered previously in linear stability studies.