Effect of liquid viscosity on drop breakup in shock wave: Modeling and physical analysis

This paper presents a computational study of droplet breakup behind a shock wave in the liquid viscosity range of 0.0003 ≤ μ ≤ 0.428 Pa s. Water, ethanol, hexane, and tridecane were used as low-viscosity liquids, while diesel fuels were used as viscous liquid samples. The calculations were performed using fixed gas parameters, as in the experiments with water at a Weber number of We = 400. The numerical methodology is based on the volume of fluid method; the large eddy simulation model was used to account for turbulence, and the technology of adapted grids with a secondary droplet size resolution of up to 20 μm was applied to describe the behavior of the interface on the main turbulent scales. An analysis of the calculations is performed based on the physical mechanisms of aerodynamic droplet breakup: Rayleigh–Taylor instability, “sheet stripping” mode, and wave crest stripping of droplet breakup via the Kelvin–Helmholtz instability mechanism. The influence of liquid viscosity on all aspects of the interaction of a drop with incident shock wave is shown—deformation, aerodynamic drag, mechanisms, and the induction period of drop breakup.