Dynamics of Ferrofluidic Drops Impacting Superhydrophobic Surfaces

TL;DR

This study investigates how ferrofluid droplets behave upon impact on various surfaces, revealing magnetic field effects that alter droplet size, velocity, and impact phenomena like jetting and oscillations.

Contribution

It introduces the influence of magnetic fields on ferrofluid droplet impact dynamics on different wettability surfaces, including superhydrophobic, with novel observations of jetting and oscillations.

Findings

Magnetic fields reduce droplet size and increase impact velocity.

Jetting phenomena occur at higher impact speeds than previously observed.

Magnetic stabilization causes amplified oscillations in superhydrophobic impacts.

Abstract

This is a fluid dynamics video illustrating the impact of ferrofluidic droplets on surfaces of variable wettability. Surfaces studied include mica, teflon, and superhydrophobic. A magnet is placed beneath each surface, which modifies the behavior of the ferrofluid by applying additional downward force apart from gravity resulting in reduced droplet size and increased droplet velocity. For the superhydrophobic droplet a jetting phenomena is shown which only occurs in a limited range of impact speeds, higher than observed before, followed by amplified oscillation due to magnetic field as the drop stabilizes on the surface.