The velocity field in hydromagnetic oscillatory flow past an impulsively started porous limiting surface with variable suction

The authors consider the two-dimensional hydromagnetic oscillatory flow of a viscous, incompressible and electrically conducting fluid, past a porous, infinite, limiting surface subjected to variable suction and moving impulsively with a constant velocity in the presence of a transverse magnetic field. Approximate solutions are obtained for the velocity field and expressions are given for the velocity, the induced magnetic field, the skin friction, and the electric current density for the magnetic Prandtl number Psub(m) = 1 and the magnetic parameter M < 1. Variations of the above quantities are presented graphically, and the authors conclude with a quantitative discussion. (Auth.)