Droplet impact on a wettability‐patterned woven mesh

Abstract

AbstractDroplet impact and breakup on meshes are relevant to a number of applications involving filters, textiles, and other spatially inhomogeneous media encountering gas‐dispersed liquids. This study presents high‐resolution simulation results of mm‐size droplets striking wettability‐patterned meshes with the goal of (a) replicating prior physical experiments, (b) identifying sensitivities to the initial conditions and wettability of the mesh wires, and (c) studying the fluid‐field dynamics when droplets strike such meshes. The insights from the present model may help to advance understanding of droplet atomization on meshes, which depends on a number of parameters that are nontrivial to control in an experimental setting. The analysis is carried out by benchmarking the numerical methods used in a commercial software package for orthogonal droplet impact on a flat smooth surface, followed by a convergence analysis, and finally, simulation of specific experiments and case studies involving wettability‐patterned mesh targets. We show that the wettability contrast between the hydrophilic and hydrophobic domains on the mesh as well as the contact angle hysteresis on each side play a critical role in determining whether liquid pinch‐off occurs. The three‐dimensional computational framework constructed in this work is a step toward predicting the postimpact behavior of droplets that strike woven meshes and other porous inhomogeneous media consisting of materials with different wetting properties.