  Linear stability analysis of the axisymmetric interface of velocity and
density discontinuity in rotating gaseous disk has been performed numerically
and analytically. Physical mechanisms leading to development of centrifugal and
Kelvin-Helmholtz instability at the kink has been analysed in detail. In the
incompressible limit it has been shown in the first time such areas in the
parameter space that Kelvin-Helmholtz instability is stabilized by the density
kink. This effect is caused by both specifical angular momentum conservation
and buoyancy. The possibility of application of obtained results to the
stability analysis of the gaseous disks of the real flat galaxies is discussed.
