High Reynolds number incompressible MHD flow under low RmRm approximation

The control of wake instabilities in the flow of an electrically conducting fluid around a sphere by means of external magnetic field is studied at high Reynolds number 500 and interaction parameter N   in the range 0.5⩽N⩽120.5⩽N⩽12 (or 22⩽M⩽11022⩽M⩽110) where M   is the Hartmann number defined by M=2NRe. By increasing the magnetic field, the flow separation is not fully suppressed, and the length of the recirculation bubble increases when N⩾2N⩾2 and the separation angle increases when N⩾5N⩾5. The pressure drag coefficient and total drag coefficient exhibits a linear dependence with N when N⩾1N⩾1. A growing inviscid rotational region is found in the downstream region and this region extends to the upstream region with increase in the magnetic field. Further, general increase in upstream base pressure and a decrease in downstream base pressure is noted. The thickness of boundary layer is determined as a function of interaction parameter.