Abstract: To deeply understand mechanism of shock wave interacting with a flame,a numerical study on a planar incident shock wave and reflected wave interacting with a spherical flame was carried out with two-dimensional Navier-Stokes equations coupled with chemical reaction. Okubo-Weiss function are proved appropriate for compressible flow by analyzing characteristic equation of velocity gradient tensor. Emphasis was placed on two-dimensional flow topology characteristics of flame zone. It shows that integral of Okubo-Weiss function conserves within flame zone after passages of shock waves. However,inner and surface of flame zone display completely different flow status. Flow compressibility basically has no effect on evolution of flame. Besides,flow topology of flame zone is mainly controlled by foci and saddle,which means deformation is dominant in flow field.

Key words: shock wave, flame, velocity gradient tensor, Okubo-Weiss function, flow topology