Universal oscillatory dynamics in capillary filling

Abstract

Capillary filling dynamics is ubiquitous in biological and natural processes. While capillary imbibition in narrow conduits has been extensively studied in the literature, any generalization in the oscillatory characteristics of the capillary front, typically observed towards the end of capillary filling processes, remains elusive. Considering Newtonian fluids, here, we demonstrate the realization of a unique universal signature of the oscillatory dynamics of the capillary front, by collapsing all relevant data in terms of the pertinent dimensionless parameters, leading to a single master curve. We further delineate the validity of our claim through extensive experiments, using four different fluids, and phase-field numerical simulations. These results may bear far reaching consequences towards explaining the capillary filling processes in a wide variety of applications ranging from nature to energy.