Abstract
The aim of this paper is to determine the exact solution of unsteady magnetohydrodynamic (MHD) flow of a rotating Oldroyd-B fluid in a porous medium over a suddenly moved flat plate. This is achieved by using the Fourier sine and Laplace transforms method. The use of this method provides a means to get a new additional term appearing in the final solution. Many interesting existing results in the literature are obtained as the special and limiting cases of our solution. Finally, some graphical results of the velocity profiles are presented for different values of the material constants. It is shown that the porosity of the medium, the rotation, and the magnetisation of the fluid have an effect on the velocity fields.