Direct numerical simulations of vibration-induced drop atomization

Atomization is a fundamental multiphase phenomenon essential in various applications from spray cooling, ink-jet printing to biomedical and drug delivery methods. Vibration-induced drop atomization (VIDA) is one such method where a liquid droplet is placed on a vertically oscillating plate which results in interfacial bursting and spray formation. However, VIDA is sparsely studied because of various intricacies as follow: (1) the poloidal dependence of acceleration on the liquid-gas interface leading to a superposed effect of Faraday and Kelvin-Helmholtz waves due to oscillatory normal and tangential stresses; (2) the non-linear interaction of a such waves form chaotic patterns which characterizes the spray formation (drop sizes and distribution); and, (3) an accurate and robust fluid dynamic model for tracking fast time-scales of the superposed interfacial waves. Hence, in this work, a three-dimensional direct numerical simulation is utilized for the first time as a proof-of-concept of VIDA. It uses a highly parallelized hybrid front-tracking level-set interface capturing method that enables a realistic visualization of the transient interfacial behaviour. The effects of the Faraday and Kelvin Helmholtz waves is demonstrated to characterize the numerous droplet formation events and their velocity distribution.