Droplet impact on a prewetted mesh

The impact of droplets on dry and prewetted meshes was investigated using high-speed photography. The prewetting resulted from previous impacts. It was observed that an increase of the Weber number We resulted in a transition from no penetration of the mesh through an incomplete penetration to a complete penetration. It was found that both penetrations could be entirely suppressed by liquid trapped in the mesh (prewetted mesh), with the height of the sessile droplet being a key factor. The phase diagram in the plane determining the expected type of impact has been determined. The transition Weber numbers for both types of penetration increased monotonically with . A model for predicting the transition thresholds is proposed and compared with experimental results. It is suggested that the impact type is determined by the momentum exchange between the impacting droplet and the liquid trapped in the mesh.