A Note on the Spatial Jet-Instability of the Compressible Cylindrical Vortex Sheet

Kurzfassung

The instability of compressible circular jets with respect to spatially growing disturbances is the subject of this note. The linearized inviscid disturbance equations have been derived for a compressible circular jet with variable temperature and density profile. The eigenvalues of the instability problem for the cylindrical vortex sheet have been computed and discussed for various Strouhal numbers, Mach numbers and temperature ratios. It is found that contrary to temporal amplification the phase velocity of spatially growing disturbances can exceed the jet velocity. Furthermore, additional disturbance modes exist in the spatial case.