Impacting of droplets on moving surface and inclined surfaces

Drop impact onto inclined and moving surfaces are seen in various applications, for example, inkjet printing, spray coating, or in agriculture; droplets impact on either the surface that is moving, inclined, or a combination of both. Studies in the literature have examined the phenomenon of drop impact in isolation, either for a moving surface, or an inclined surface. Therefore, we conducted a comparative study for drop impact onto moving and inclined surfaces to see if they can be considered as equivalent systems. We used high speed imaging and examined the spreading and splashing of droplet impact onto both inclined and moving surfaces, having the same normal and tangential (in-plane) velocities. Various liquids with viscosities and surface tensions in the range of 1-5 cSt 17.4-72.8 mNm, respectively, were used. We demonstrated that both systems are equivalent to one another, considering either the initial spreading behavior of droplets, or splashing. Different types of splashing seen on inclined and moving surfaces are similar regardless of system. Finally, a new type of splashing named "split splashing"was also reported. This type of splashing is seen only when the normal velocity relative to tangential velocity is very low.