Vorticity generation and flame distortion induced by shock flame interaction

The vorticity generation and flame distortion by the shock propagation through a cylindrical H₂/air flame are investigated numerically with detailed chemistry. it is shown that flame distortion and the appearance of the second shock waves greatly affects the total circulation. For strong shock wave, the results show that the flame distortion and interaction of the second shock waves yield subscale vortices. A comparison between the present prediction and the theory reveals that the predicted total circulation is lower than that given by theory. The results also show that the shock flame interaction results in significant distortion and break-up of the flame. The effects of shock strength on the flame distortion, the length of flame front, and the mass burning velocity are examined. The results show that both the total mass burning velocity and the length of the flame front increase dramatically with the shock Mach number. The mean local burning velocity is obtained by normalizing the total burning velocity with the length of the flame front. A good agreement between the mean local burning velocity and the burning velocity of laminar H₂/air flame is obtained. It is concluded that the flame distortion induced by the shock flame interaction is very close to the laminar flamelet regime.