On the development of characteristics in an oscillating, rotating fluid (Q1069828)

A source of fluid with an oscillatory strength, which is situated on the axis of a rotating fluid, commences to act at time \(t=0\). We describe how inviscid, geostrophic forces lead to the development of the characteristic cone when the frequency of oscillation is less than twice the frequency of rotation. Eventually, viscous forces become important when the time is \(O(E^{-1/3})\), where E is the small Ekman number, in forming the thin shear layer along the surface of the cone.