Possibility of controlled ejection of ferrofluid grains from a magnetically ordered ferrofluid using high frequency non-linear acoustic pulses – a particle dynamical study

Abstract

We consider a model dilute ferrofluid that is subjected to a strong, homogeneous magnetic field directed perpendicular to the surface of the ferrofluid, such that there is a chain formation in the direction perpendicular to the surface of the liquid. We study the propagation of impulses generated at high-frequency across finite times through the ferrofluid chains. Our numerical analysis shows that a very high-frequency sequence of non-linear acoustic pulses of appropriate magnitudes, initiated at the base of the container, can lead to the ejection of desired number of ferrofluid grains through the liquid–air interface. The proposed mechanism, if successfully realized in the laboratory, could help design a nozzle-free, ultrafast, ink-jet printer of unparalleled resolution.