Unsteady Magnetohydrodynamic Flow at the Forward Stagnation Point

The unsteady flow of an electrically conducting fluid, impulsively brought in motion with a constant velocity from rest at the forward stagnation point of an infinite plane wall which is an electric insulator, is considered. When a magnetic field is applied normal to the wall, its effects on the transient phenomena to the steady flow case are studied by a usual unsteady approach. The derived fundamental equation on the assumption of small magnetic Reynolds number is solved both by an expansion method into power series and by a numerical method employing the difference-differential method. Solutions obtained by series expansion method are found to be invalid for large times. On the other hand, the difference-differential method may present well behaved solutions for the transition region in the flow impulsively started from rest and those of steady flow. Numerical results are given for the velocity profile, skin friction and time required to attain a value of skin friction within 0.1% of that of steady flow case.