Rheology Projects:
Stability of Two-Layer Poiseuille Flow of Thixotropic and Viscoplastic Fluids
One strategy for eliminating interfacial instabilities in multi-layer flow systems is using a viscoplastic fluid as the lubricating fluid. The unique feature of a viscoplastic fluid is that it possesses yield stress. The yield stress is a stress value that separates the flow behaviour into two distinctly different qualitative regimes. For shear stresses in the fluid that are below the yield stress, the fluid has a solid-like structure and moves as a rigid body. For shear stresses above the yield stress, the fluid deforms and flows. In this project, we use a simple rheological model to describe the thixotropic behaviour of heavy crude oil in the context of spectral/hp Elements. The core fluid is described by Moor fluid, and the interfacial instability is removed by a Viscoplastic fluid as a lubricant. The figure shows the contour of phase function of core-annular flows of a Newtonian-Bingham and a Thixotropic-Bingham fluid.
