The impact dynamics and impact force of ferrofluid droplets with various shapes

This study investigates the impact dynamics and forces exerted by non-spherical liquid drops on solid substrates, a topic traditionally centered on spherical drops. By employing ferrofluid to create droplets of diverse shapes, we examine the effects of aspect ratio and superellipse power index on drop impact behavior. Our results demonstrate that the initial expansion phase is universally governed by the superellipse power index, and the final maximum spreading radius and splash volume are systematically influenced by the aspect ratio. Furthermore, our investigation into the impact forces of variously shaped droplets reveals a significant dependency on both the aspect ratio and the superellipse power index. Notably, the maximum impact force increases with the aspect ratio of width to length, as well as with higher superellipse power indices. These experimental results agree well with predictions from a simple high-stress cylinder model. This research expands the understanding of drop impact physics beyond spherical geometries, showcasing the potential of manipulating drop shape to tailor impact outcomes [1].

[1] Q Liu et al, Nature Communications, Volume 12, 3068, 2021.