Computational Study of Planar Shock Bubble Interactions

The physics of shock-bubble interaction (SBI) is the basic of understanding shock accelerated inhomogeneous flows. When a shock wave propagates through a medium of nonuniform thermodynamic properties, complicated process like, shock refraction, reflection and diffraction will occur. At the edges of the bubble geometry, vortexes will be induced by shock compression and acceleration of the medium. The interaction of planar shock wave with square light bubble, square heavy bubble will be studied by using the Integro-differential scheme (IDS). Numerous experiments have confirmed that this type of problems contain specific fundamental fluid physics that does not lend themselves to simulations without severe numerical challenges. Numerical challenges of great significance to this analysis are the evolution of the Richtmyer-Meshkov Instability (RMI). Which typically found in the shock bubble interaction problems due to the shock accelerating the density perturbations. The objective of the shock heavy bubble problem is to evaluate the capability of the IDS as a tool to solving the unsteady multiphase shock-bubble interaction. Specifically, in this effort, the unsteady interaction of a Mach 1.17 planar shock wave with a square sulfur hexafluoride (SF6) bubble surrounded with air is studied firstly. Furthermore, the unsteady interaction of a Mach 1.21 planar shock wave with a square helium bubble surrounded with nitrogen will be conducted which considered as shock light bubble interaction. It is noteworthy to mention that the IDS captured both the regular and the irregular unsteady refraction phenomena within the flow field. In addition, the IDS unsteady simulation was able to reproduce the all SBI known phenomena, such as, shock rarefaction and reflection, shock-interface interaction, vorticity generation and RM instability. Single-mode RMI will be simulated, which the square bubble proved the misalignment between pressure gradient and local density gradient only at the edge of the bubble. An outward jet structure form on the bubble interfaces, will be captured while the bubble in heavy than the ambient gas, due to shock focusing phenomena, which indicated IDS has the capability to capture RM Instability. In this paper, the main focus is the capabilities of IDS to capture fluid structs due to compression and acceleration of medium inside a given bubble, which all bubble contains inert gases, chimerical reaction will not be conducted in this paper.