THREE-DIMENSIONAL MHD STAGNATION POINT FLOW OF A NEWTONIAN AND A MICROPOLAR FLUID

The steady three-dimensional stagnation-point flow of an electrically conducting Newtonian or micropolar fluid in the presence of a uniform external magnetic field ${\H}_0$ is analysed and some physical situations are examined. In particular, we prove that, if we impress an external magnetic field ${\H}_{0}$, and we neglect the induced magnetic field, then the steady three-dimensional MHD stagnation-point flow is possible if, and only if, ${\H}_0$ has the direction of one of the coordinate axes. In all cases it is shown that the governing nonlinear partial differential equations admit similarity solutions. We find that the flow has to satisfy an ordinary differential problem whose solution depends on ${\H}_{0}$ through the Hartmann number $M^2$. Finally, the skin-friction components along the axes are computed.