The nonlinear stability of plane poiseulle flow for non-newtonian power series fluid

Non-Newtonian fluid is a kind of fluid whose components of stresstensor aren't the linear functions of components of the strain rate tensor. Non-Newtonian fluid is being processed in many kinds of modern industry. Stability of flows for Non-Newtonian fluid is of important application. In this article we calculate subcritical threshold of flow which occurs in polymer-processing when the melting substance is driven through two parallel fixed boundaries. Project supported by the National Natural Science Foundation of China