Non-Newtonian fluid mechanics affords an excellent opportunity for studying many of the mathematical methods which have been developed to analyze nonlinear problems in mechanics.
The flow of an incompressible fluid of grade three past an infinite porous flat plate, subject to suction at the plate, is governed by a nonlinear differenial equation that is particularly well suited to demonstrate the power and usefulness of three such techniques. We establish an existence theorem using shooting methods. Next we investigate the problem using a perturbation analysis. It is not clear that the perturbation solution converges and thus may not be the appropriate solution for a certain range of a material constant (which is not the perturbation parameter).
Finally, we employ a numerical method which is particularly suited to the problem in question.