Boundary-Layer Transition on Broad Cones Rotating in an Imposed Axial Flow

This paper presents stability analyses for the boundary-layer flow over broad cones (half-angle psi > 40 degrees) rotating in imposed axial flows. Preliminary convective instability analyses are presented that are based on the Orr- Sommerfeld equation for a variety of axial-flow speeds. The results are discussed in terms of the limited existing experimental data and previous stability analyses on related bodies. The results of an absolute-instability analysis are also presented which are intended to further those by Garrett and Peake [Garrett, S.J., and Peake, N., "The Absolute Instability of the Boundary Layer on a Rotating Cone," European Journal of Mechanics, B/Fluids, Vol. 263, 2007, pp. 344-353.] through the use of a more rigorous steady-How formulation. Axial flow is seen to delay the onset of both convective and absolute instabilities.