The Study On Gas Bubble Jet Phenomenon Under Shock Wave

The interaction of shock wave and gas cylinder/bubble interface is a complexprocess, because of which not only contains the phenomena of shock refraction,reflection, diffraction and scattering, but also the gas property that may influence thedevelopment of the wave structure. Jet phenomenon of high density gascylinder/bubble under shock wave is very interesting, the appearance of jet structure ishighly related to the shock wave strength, and there are differences between the jetstructures formed by gas cylinder and by bubble, but the researches on jetphenomenon is rarely seen, analysis on the wave structure development is not clear, asa result, it is worthwhile to elucidate and analyze the gas cylinder/bubble jetphenomenon.Take R₂₂cylinder/bubble as an example, the gas cylinder/bubble jet phenomenonunder shock wave is elaborated. The cases with or without gas jet phenomenon underdifferent shock strengths are compared in order to examine the reason of theappearance of jet structure. In the program codes, Level set method is applied tocapture the material interfaces, real ghost fluid method （rGFM） is used to define theinterfacial boundary conditions, fifth order WENO scheme and third order TVDRunge-Kutta method are employed to solve the spatial and time discretization of theEuler equations. The numerical solutions agree well with the experiments.A series of shock-cylinder/shock-bubble interaction cases are simulated, basedon which a summary is made on the laws of jet phenomenon and wave structurefeatures in the process of jet development are concluded: gas cylinder/bubble jetphenomenon under shock wave appears only within a certain range of the incidentshock strength; in the cases of gas jet phenomenon, a shock wave focal point andMach stem/disk appears and develops in the cylinder/bubble, and impacts directly onthe material interface; but if the width/diameter of the Mach stem/disk exceeds acertain extent, the gas jet fails to appear; comparing with the gas cylinder case, themoment of focal point in the gas bubble is earlier, while the sectional area variance issmaller.