In this study, the pseudo plastic model is used to obtain the solution for
the steady thin film flow on the outer surface of long vertical cylinder for
lifting and drainage problems. The non-linear governing equations subject to
appropriate boundary conditions are solved analytically for velocity profiles
by a modified homotopy perturbation method called the Optimal Homotopy
Asymptotic method. Expressions for the velocity profile, volume flux, average
velocity, shear stress on the cylinder, normal stress differences, force to
hold the vertical cylindrical surface in position, have been derived for both
the problems. For the non-Newtonian parameter ?=0, we retrieve Newtonian
cases for both the problems. We also plotted and discussed the affect of the
Stokes number St, the non-Newtonian parameter ? and the thickness ? of the
fluid film on the fluid velocities.
Thin film flow down a porous substrate in the presence of an insoluble surfactant: Stability analysis