The influences of the acoustic impedance and shock strength on the jet formation in shock-heavy gas bubble interaction are numerically studied in this work. The process of a shock interacting with a krypton or a SF6 b...The influences of the acoustic impedance and shock strength on the jet formation in shock-heavy gas bubble interaction are numerically studied in this work. The process of a shock interacting with a krypton or a SF6 bubble is studied by the numerical method VAS2D. As a validation, the experiments of a SF6 bubble accelerated by a planar shock were performed. The results indicate that, due to the mismatch of acoustic impedance, the way of jet formation in heavy gas bubble with different species is diversified under the same initial condition. With respect to the same bubble, the manner of jet formation is also distinctly different under different shock strengths. The disparities of the acoustic impedance result in different effects of shock focusing in the bubble, and different behaviors of shock wave inside and outside the bubble. The analyses of the wave pattern and the pressure variation indicate that the jet formation is closely associated with the pressure perturbation. Moreover, the analy- sis of the vorticity deposition, and comparisons of circulation and baroclinic torque show that the baroclinic vorticity also contributes to the jet formation. It is concluded that the pres- sure perturbation and baroclinic vorticity deposition are the two dominant factors for the jet formation in shock-heavy gas bubble interaction.展开更多
The shock-induced ignition and detonation wave propagation in reactive elliptic premixed bubbles are numerically studied.Close attention is paid to the bubble geometry effect on the ignition pattern and the ensuing bu...The shock-induced ignition and detonation wave propagation in reactive elliptic premixed bubbles are numerically studied.Close attention is paid to the bubble geometry effect on the ignition pattern and the ensuing bubble behavior.Five elliptic bubbles with different aspect ratios are examined.According to the numerical results,three typical ignition patterns are identified under the same incident shock strength and the underlying mechanisms are interpreted.The difference in ignition pattern shows that,comparing with the inert shock-bubble interaction,the geometry effect in reactive shock-bubble interaction(RSBI)has more implications.In addition to the aspect ratio,the ignition location and the distance from the ignition spot to the nearest/farthest bubble surface should also be considered as elements of the geometry effect in RSBI.展开更多
基金supported by the National Natural Science Foundation of China (10972214 and 11172278)the Fundamental Research Funds for the Central Universities (WK2090050014)
文摘The influences of the acoustic impedance and shock strength on the jet formation in shock-heavy gas bubble interaction are numerically studied in this work. The process of a shock interacting with a krypton or a SF6 bubble is studied by the numerical method VAS2D. As a validation, the experiments of a SF6 bubble accelerated by a planar shock were performed. The results indicate that, due to the mismatch of acoustic impedance, the way of jet formation in heavy gas bubble with different species is diversified under the same initial condition. With respect to the same bubble, the manner of jet formation is also distinctly different under different shock strengths. The disparities of the acoustic impedance result in different effects of shock focusing in the bubble, and different behaviors of shock wave inside and outside the bubble. The analyses of the wave pattern and the pressure variation indicate that the jet formation is closely associated with the pressure perturbation. Moreover, the analy- sis of the vorticity deposition, and comparisons of circulation and baroclinic torque show that the baroclinic vorticity also contributes to the jet formation. It is concluded that the pres- sure perturbation and baroclinic vorticity deposition are the two dominant factors for the jet formation in shock-heavy gas bubble interaction.
基金This work was supported by the National Natural Science Foundation of China(Grant 12002102).
文摘The shock-induced ignition and detonation wave propagation in reactive elliptic premixed bubbles are numerically studied.Close attention is paid to the bubble geometry effect on the ignition pattern and the ensuing bubble behavior.Five elliptic bubbles with different aspect ratios are examined.According to the numerical results,three typical ignition patterns are identified under the same incident shock strength and the underlying mechanisms are interpreted.The difference in ignition pattern shows that,comparing with the inert shock-bubble interaction,the geometry effect in reactive shock-bubble interaction(RSBI)has more implications.In addition to the aspect ratio,the ignition location and the distance from the ignition spot to the nearest/farthest bubble surface should also be considered as elements of the geometry effect in RSBI.
