Shock-Driven Acetone Droplets at High Weber Numbers: Deformation and Kinematics*

Shock-driven droplet deformation is a complex process that involves the formation of interfacial instabilities on the droplet surface leading to breakup. Understanding the fundamental physics of droplet breakup under shock conditions is pertinent for applications in propulsion and combustion systems. We investigate the deformation and kinematics of a 10 µm acetone droplet driven by a Mach 2.4 shock wave at a Weber number of 565, using 2D axisymmetric numerical simulations. The simulations^1,2 employ high-fidelity numerical methods and a level-set based sharp interface approach to describe complex interfacial instabilities and subsequent droplet breakup dynamics. Droplet morphology reveals the growth of Kelvin-Helmholtz instabilities on the droplet surface and their role in droplet deformation and breakup, characterized by the formation of thin ligaments and shedding. Droplet relative deformation and kinematics from the simulations are compared with predictions from the original and modified versions of the Taylor Analogy Breakup model. Discrepancies between simulation and model predictions at late times highlight the need for further improvements to these models.

¹P. Bigdelou et al., Comput. Fluids, 233, 105250, (2022)

²P. Tarey et al., Int. J. Multiph. Flow, 174, 104744, (2024)