  Direct observation of the droplet breakup process in high-speed gas flows is
a critical challenge that needs to be addressed to elucidate the physical
mechanisms underlying the fragmentation phenomenon. Here, we present a
high-magnification and high-speed shadowdograph technique that allows the
visualization of this process over its whole evolution and resolves detailed
features of the breakup zone. The developed experimental method uses a
high-speed camera equipped with a long-distance microscope. The backlight
illumination source is provided by the laser-induced fluorescence of a dye
solution that delivers short pulses at a high-repetition rate. Artefacts
resulting from the laser coherence are therefore reduced.
