High-magnification shadowgraphy for the study of drop breakup in a high-speed gas flow

TL;DR

This paper introduces a high-magnification, high-speed shadowgraphy technique using laser-induced fluorescence to visualize droplet breakup in high-speed gas flows, enabling detailed observation of the entire process.

Contribution

The study develops a novel experimental method combining high-speed imaging and laser-induced fluorescence for detailed visualization of droplet breakup.

Findings

Successful visualization of droplet breakup process

Resolution of detailed features of the breakup zone

Reduction of laser coherence artefacts

Abstract

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.