Droplet deformation and breakup are important phenomena in the atomization process due to their impact in the final distribution of droplet size. For many applications such as spray painting, coating or fuel injection, it is desirable to be able to obtain appropriate fragmentation sizes. Turbulence is one of the main mechanisms through which secondary breakup occurs. Several authors relate the turbulent droplet breakup to a resonant mechanism reached by their free oscillations.
A theoretical framework for the droplet oscillations for each individual mode using a spherical harmonic decomposition is considered, with the help of the library PySthools. This is appraised from direct numerical simulation (DNS) data using the in-house code Archer and the spherical harmonics library of the post-processing tool pyarcher. The present report aims to document the developed numerical tool and its appropriateness on a number of test cases.