An analytical study of normal shock wave induced vortex breakdown has
been undertaken. In this inviscid axisymmetric analysis, the response
of supersonic streamwise vortices to imposed normal shocks has been de
termined by modeling the rotational core of the vortex as a slender, s
wirling layer. For vortex/shock combinations of increasing strength, t
he analysis predicts an ever increasing axial velocity deficit in the
vortex core. Vortex breakdown is presumed to occur if a vortex/shock c
ombination Leads to how stagnation at the vortex axis. The results of
this study indicate that an inverse relationship exists between vortex
swirl and freestream Mach number at breakdown. The breakdown limit cu
rve generated using this analysis shows good correlation with establis
hed experimental results, indicating that the onset of normal shock wa
ve induced vortex breakdown can be predicted with a relatively simple
flow model and without recourse to numerical simulation. Interpretatio
n of same normal shock wave/vortex interaction experiments in light of
the predictions suggests that the phenomenon previously known as supe
rsonic vortex distortion is a form of vortex breakdown.