Influence of the Aspect Ratio on the Stability of Pseudoplastic Fluids Between Rotating Cylinders

Pseudoplastic circular Couette flow in annulus is investigated in finite gap. The onset of the Taylor vortices is determined theoretically by solving the conservation equations, constructing the solution path as the inner cylinder speed rises and detecting the critical conditions. The obtained governing equations were solved by the spectral method. The curved streamlines of the circular Couette flow can cause a centrifugal instability leading to toroidal vortices, known as Taylor vortices. A range of parameters is found in which the combination of shear thinning and gap effect leads to destabilizing the vortex structure indicated as the point of Hopf bifurcation. Comparison with existing measurements on pseudoplastic circular Couette flow results in good agreement.