Abstract
The evolution of shock-sulfur hexafluoride (SF6) bubble interaction is investigated using a detailed three-dimensional numerical simulation. The influences of the end wall distance on the bubble evolution are analyzed by using the high-resolution simulations. The results show that vorticities mainly emerge at the interfaces of the shock wave and the SF6 bubble, and a downstream jet is formed, owing to the impingement of the high pressure in the vicinity of the downstream pole of the bubble and the induction of nearby vorticities. Besides, the big vortices of the SF6 bubble could interact with the walls in the y-direction to increase the bubble volume. When the end wall distance is shortened, a short and wide downstream jet is formed, owing to the untimely interaction of the reflected shock wave with the distorted SF6 bubble. Also, a new upstream jet emerges behind the impingement of the reflected shock wave, and there is no interaction between the distorted SF6 bubble and the wall in the y-direction until a very late time. From a quantitative point of view, the discrepancy between the bubble volume and effective bubble volume is larger in the case with a long end wall distance, which has enhanced vorticities and strengthened bubble-wall interaction. Moreover, the reflected shock wave has a dominant compression effect on the distorted SF6 bubble evolution for the two cases with different end wall distances, but for the case with a longer end wall distance, the bubble-wall interaction has a more significant influence than the influence of vorticities on the bubble volume increase. The computational results demonstrate the three-dimensional effects of shock-SF6 bubble interactions, which have not been seen in previous two-dimensional simulations.
Highlights
The interaction of a shock wave with a bubble features in a broad range of scientific and engineering applications and has been used widely as a canonical reference system to test new numerical methods for compressible interfacial flows.1 Even so, the many complicated physics and chemical processes involved have not been fully understood at present.During the shock-bubble interaction, the ambient unshocked gas has density ρ1 and the unshocked bubble gas has density ρ2; an Atwood number At = (ρ2 − ρ1)/(ρ2 + ρ1) can be defined
During the interaction between the reflected shock wave and the distorted bubble, a slender downstream jet is found in Fig. 2(c), and the reflected shock wave interacts with the jet at this time instant
The reflected shock wave has passed through the distorted bubble completely in Fig. 2(d), and the SF6 bubble is further compressed and more vorticities emerge throughout the distorted bubble interface
Summary
The interaction of a shock wave with a bubble features in a broad range of scientific and engineering applications and has been used widely as a canonical reference system to test new numerical methods for compressible interfacial flows. Even so, the many complicated physics and chemical processes involved have not been fully understood at present. The influences of different Atwood numbers (−0.8 < At < 0.7) and incident shock intensity (1.1 < Ma ≤ 5.0) were investigated, and the time-dependent volumetric compression, circulation, and extent of mixing in the shocked-bubble flow were analyzed. They found that the three-dimensional effects were relatively insignificant with the increasing incident shock intensity.. The evolution of the three-dimensional distorted SF6 gas bubble and shock wave is presented and analyzed in detail, and the influence of the reflected shock wave on the bubble deformation process is scrutinized
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
