Regimes of Head-On Collisions of Equal-Sized Binary Droplets

Through molecular dynamics simulations, head-on collision processes of two identical droplets with a diameter of 10.9 nm are elaborately scrutinized over a wide range of impact Weber numbers (from 6.7 to 1307) both in vacuum and in an ambient of nitrogen gas. As the impact Weber number exceeds a certain critical value, a hole or multiple holes in apparently random locations are observed in the disklike structure formed by two colliding droplets....