The rotating sliced cylinder model has its origins in simulations of the large scale wind-driven ocean circulation. The model consists of a rotating circular cylinder with a sloping planar base and a lid which rotates at a rate slightly different from that of the background rotation. Numerical models for the inviscid flow, the boundary-layer flow and the viscous flow equations in this configuration are described and the flow patterns produced by them are compared. Laboratory experiments were also performed and the results are presented as validation of the numerical models. The unsteadiness of the flow in some parameter régimes which was noted by other authors (Beardsley, 1969, 1973a, b and Beardsley and Robbins, 1975) appears to be caused by instability of the separated boundary-layer flow. The separated flow has some unique features due to the effect of the driving force exerted on the flow by the rotating lid and these are also described.