Convective and absolute instabilities in the boundary layer over rotating spheres with surface mass flux and incident axial flow

We consider the effect of surface mass flux and forced axial flow on the boundary-layer flows over rotating spheres, with a view to establishing flow-control mechanisms for rotating flows of engineering significance. A theoretical study is presented which considers the onset of convective instability modes (both stationary and travelling relative to the rotating surface) and local absolute instability. Suction is found to be universally stabilising in terms of the delayed onset of both instability types. Extensive theoretical data are presented for future comparison to experiments.