Structure of absolute instability in 3-D boundary layers: Part 2. Application to rotating-disk flow

Abstract

Rotating-disk flow is taken as a typical example of three-dimensional boundary layers. Numerical computations of localized disturbances according to the propagation theory given in Part 1 are made with a simplified system of stability equations to show if the conditions of absolute instability can be satisfied in this simple flow. The results indicate no such particular amplification of disturbances near a zero of the complex group velocity. It is also shown how initially localized disturbances propagate and develop into quite a large amplification of some limited wave-number components at a downstream station.