Date of Award


Degree Type


Degree Name

Doctor of Philosophy


In this thesis we have investigated unsteady circular Couette flow for Non-Newtonian fluids of power law behaviour. We considered two specific problems: (1) A solid cylinder rotating in a power law fluid of infinite extent and (2) A power law fluid filling the gap between two concentric rotating cylinders.;Due to the nonlinearity of Non-Newtonian constitutive equations, velocity disturbances from a rotating cylinder propagate through the fluid with finite speed. The existence of this moving velocity disturbance front was observed in the analytic similarity solutions and numerical solutions. For the problem with one cylinder two numerical methods were used to determine the velocity and shear stress distributions: (1) The Method of Lines combined with the Shooting method, and (2) A front fixing transformation was employed and the resulting problem solved via various implicit (including Crank-Nicolson) finite difference schemes.;For the two cylinder problem the velocity distribution was obtained via the Method of Lines together with a variable step-size finite difference method. For both problems the temperature distribution was obtained numerically via an implicit finite difference method. The interaction effect between the angular velocity and the thermal field was addressed.;The centrifugal stability of the flow was analyzed analytically and numerically. The supercritical flow (Taylor-vortex flow and wavy Taylor-vortex flow) was determined through nonlinear stability analysis. The results were compared with experimental ones and previous analytic investigations for newtonian fluids.;The obtained results were analyzed and conclusions were drawn upon the rheo-logical effects and temperature distribution of the power law fluids.



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