Beschreibung:
<p>The viscous flow in a semi-infinite fluid above a porous oscillating disk with unsteady normal velocity in a rotating frame is studied. Expressions for velocity and skin friction are obtained. For the case of suction, the oscillations are contained in boundary layers of finite thickness. In the case of injection, resonance occurs when the imposed frequency is twice the angular velocity of rotation. It is found that the resonance can be avoided under certain conditions.</p>