Flow and temperature fields in an annulus between two concentric cylinders have been examined in this study. While the outer cylinder is stationary, the inner cylinder is rotating with a constant angular speed. A homogeneous and isotropic porous layer is press-fit to the inner surface of the outer cylinder. The porous sleeve is saturated with the same fluid that fills the annulus.

In the first part of the study, the two-dimensional Brinkman-extended Darcy equations are used to model the flow in the porous layer while two-dimensional Navier-Stokes equations are used for the fluid layer. Also two-dimensional energy equations are used to model the temperature fields in the porous and fluid layers. The conditions applied at the interface between the porous and fluid layers are the continuity of temperature, heat flux, velocity and shear stress. Analytical solutions have been obtained. Through the solutions obtained, the effects of Darcy number, porous sleeve thickness, Brinkman number and thermal conductivity ratio on the velocity and temperature profiles are studied.

In the second part, the problem is extended to three-dimensional case. In this part, the main objective is to investigate the effects of the porous sleeve properties and its geometry on the flow in the annulus. To this end, three-dimensional momentum equations are formulated for the porous and fluid layers separately. By the introduction of vorticity function in the angular direction, and use of the continuity equation, vorticity-velocity equations for the flows in the porous and fluid layers are obtained. These equations have been solved numerically and solutions for all three components of velocity and angular vorticity have been obtained for both layers. Solutions obtained show that a presence of the porous sleeve has significant effects on the flow stability in the annulus.