Chain oscillations in liquid jets

Abstract

Pour coffee into a mug, and you might notice that the water cascading from the jug resembles a chain: A series of ``links'' oriented at 90\ifmmode^\circ\else\textdegree\fi{} to one another. Such oscillating jets occur frequently in our daily lives, but their origin is still not fully understood. In this study, we performed experiments and direct numerical simulations to show that the wavelength and amplitude of the jet's oscillations and surfaces are directly linked to the flow rate and size of the opening through which the liquid flows.