Effect of Droplet Modes on Secondary Fragmentation

A Newtonian drop undergoes secondary (non-vibrational) breakup under impulsive acceleration when the flow Weber number is greater than critical Weber number (We_cr). For a spherical droplet, We_cr depends on density ratio ρ as well as drop (Oh_d) and ambient (Oh_o) Ohnesorge numbers. However in nature, droplets are rarely spherical. Natural droplets almost always show free surface oscillations in various modes. These non-spherical shapes can have a significant impact on droplet deformation and breakup, depending on its mode as well as the phase of the oscillation. To illustrate this behavior, droplets with different oscillation modes are studied using numerical simulations and compared against analogous spherical droplets. Significant changes to both breakup morphology and We_cr are observed due to a change in initial droplet shape.