On the channel flow of yield stress fluids with an internal microstructure

Thin films consisting of polymer solutions are typically produced through a combination extrusion and shearing processes, where the anisotropic, non-Newtonian solution is deformed subjected to thermal treatment. This paper investigates polymeric thin by studying channel flow rheology that experience yield stress. The material described transversely isotropic fluid (TIF) model, which contains behavior term related microstructure distortion. Our results show this distortional stress able resist pressure gradient, non-trivial distributions can exist in absence flow. represents significant improvement over existing viscosity-based models (e.g., Heschel–Bulkley model). unyielded state achieved as end result transient process, gradient produces short-lived ceases when opposing stresses from distortion produced. Predictions TIF model compared with phenomenological Saramito model. Both found predict yielding threshold exceeded. In both cases, velocity profile Newtonian near wall, while plug flows encountered close centerline.