  In this paper, we study the unsteady hydromagnetic flow of a Walter's fluid
(Model B') down an open inclined channel of width 2a and depth d under gravity,
the walls of the channel being normal to the surface of the bottom under the
influence of a uniform transverse magnetic field. A uniform tangential stress
is applied at the free surface in the direction of flow. We have evaluated the
velocity distribution by using Laplace transform and finite Fourier Sine
transform technique. The velocity distribution has been obtained taking
different form of time dependent pressure gradient g(t), viz., i) constant ii)
exponential decreasing function of time and iii) Cosine function of time. The
effects of magnetic parameter M, Reynolds number R and the viscoelastic
parameter K are discussed on the velocity distribution in three different
cases.
