Stability of Inviscid Axisymmetric Jet with a Pair of Longitudinal Vortices

Abstract

Stability of wake field with a pair of longitudinal vortices is discussed by a simplified in-viscid flow model. The model is composed of an axisymmetric jet, a vortex doublet inside it as the limiting configuration of a pair of vortices, and a cross flow to keep the vortex doublet inside the jet. The theoretical analysis based on the linear instability theory shows that the whole flow field is unstable and the flow due to vortices weakens the instability of jet at the side of the cylindrical jet surface facing the cross flow but magnifies it at the back side of the surface.