Resonance Type Instabilities in the Gaseous Disks of the Flat Galaxies II. The stability of solitary vortex sheet

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.