  Inertial particles advected by a background flow can show complex structures.
We consider inertial particles in a 2D Taylor-Green (TG) flow and characterize
particle dynamics as a function of the particle's Stokes number using dynamic
mode decomposition (DMD) method from particle image velocimetry (PIV)
like-data. We observe the formation of caustic structures and analyze them
using DMD to (a) determine the Stokes number of the particles, and (b) estimate
the particle Stokes number composition. Our analysis in this idealized flow
will provide useful insight to analyze inertial particles in more complex or
turbulent flows. We propose that the DMD technique can be used to perform a
similar analysis on an experimental system.
