Geometrically driven liquid wicking: numerical study and experimental validation

Abstract

Liquid film or drop wicking on solid surface without any external energy input is highly desirable in specific industrial processes. This paper proposes a numerical study of the 
 dynamics of
 liquid wicking on geometrically structured flat surface. We consider structures deduced from flat surface by super-imposing a series of identical parallel channels, the ensemble 
 being made of the same material.
 Channels exhibit arrow-shaped patterns. We analyse drop wicking on such a structure using numerical simulation and experiment. Both approaches reveal non symmetric wicking clearly
 exhibiting 
 a privileged direction. The simulation captures the evolution of the liquid/air interface at smaller time scales and reveals wicking with rapid pulses suggested by the
 experiment.

Directional Water Wicking on a Metal Surface Patterned by Microchannels

“…However, at the mesoscopic scale, it is still relevant to consider the contact angle θ [45]. Therefore, following [42] we assume that the contact angle during the front dynamics is equal to the static contact angle θ. Equations of the VOF method are detailed in the present framework in [37].…”

“…However, none of these references have attempted to simulate the time evolution of liquid drops far from quasi-static regime in complex geometries such as the fin-shaped structures considered by [16] nor a periodic distribution of tilted pillars [18]. A presentation of the experiment and a first numerical analysis reported in [37] suggested that the fluid inertia cannot be neglected during the wicking. Simulating a free flow surface wetting dynamics with the complete Navier-Sotkes in a complex geometry is a challenging task.…”