Abstract: An approach combining the fifth Upwind Compact Difference Scheme and Group Velocity Control is applied to simulate directly the interaction of shocks and the density stratified interface of light-gas cylinder.Some research about the generation and development of vorticity and the distortion of edge of cylinder is done.The instability of cylinder density-interface is analyzed.Main character of the linear developing phase is that the gas of higher density goes into the one of lower denstiy at a constant velocity and the spike structure is formed and the character of the nonlinear developing phase is that a pair of vortex structures rotating adversely are formed on both sides of the top of the spike.The numerical solution accords with the experiment.

Key words: fifth upwind compact difference scheme, group velocity control, Richtmyer-Meshkov instability, density-stratified interface of light-gas cylinder, baroclinic effect