Flow structures formed by axisymmetric spinning bodies

The study of flow structures in a three-dimensional boundary layer attached to an axisymmetric rotating body could provide a basis for obtaining a practical understanding of the flight dynamics of such a spinning body. Difficulties arise, however, with respect to the conduction of such a study. These difficulties are mainly related to questions regarding the transition to instability in the boundary layer. The present investigation is concerned with such questions. In the context of this investigation, experiments were conducted in a small low-turbulence wind tunnel. On the basis of the obtained results, it is concluded that the Tollmien-Schlichting instability is induced by three-dimensional spiral vortices.