The stability of spiral flow between rotating cylinders

The stability of viscous flow under an axial pressure gradient between two co-axial cylinders rotating in the same direction is considered. The critical Taylor number (T<SUB>c</SUB>) for the onset of instability is then a function of the Reynolds number (R) of the mean axial flow. A perturbation theory valid in the limit R&#8594;0 is developed and the formula T<SUB>c</SUB>(R) = T<SUB>c</SUB>(0) + 26.5R<SUP>2</SUP> (R&#8594;0) is established