Ansys Polyflow is a finite-element program primarily designed for the analysis of industrial flow processes dominated by nonlinear viscous phenomena and viscoelastic effects. It is used in a wide variety of applications, including polymer and rubber processing, food rheology, glassworks furnaces, and many other problems involving the flow of non-Newtonian fluids. The theoretical foundation of Ansys Polyflow is provided by the general principles of continuum mechanics, together with phenomenological or kinetic theoretical models for describing the rheological behavior of the fluid.

The range of validity of the Newtonian constitutive equation is limited to low-molecular-weight, homogeneous liquids. The flow phenomena observed with polymeric fluids, for example, cannot be predicted by the classical Navier-Stokes equations. Non-Newtonian behavior has many facets. Among them are the shear-rate dependence of the shear viscosity, the presence of normal stresses in viscometric flows, high resistance to elongational deformation, and memory effects associated with the elasticity of the fluid. The theoretical challenge is to translate the complex rheological behavior of polymeric fluids into suitable equations, and to use these models to predict flows in complex geometries.