Crossflow instability in rotating disk boundary-layer

The paper discusses the transition process of a rotating disk boundary-layer experimentally in detail. It is found that the number of crossflow vortices n is dependent on square root of the rotation Reynolds number, and the physical nature of the 'wave doubling', which is the expression of the deformation of sinusoidal hot wire signal representing the crossflow vortices into double amount of the fundamental frequency, was investigated by using both visualization technique and a hot wire measurement, and found out that the phenomenon is the non-linear deformation of the crossflow vortices in its inner structure.