Interface evolution characteristics of dual droplet successive oblique impact on liquid film

The dynamic characteristics of dual droplet successive oblique impact on a thin liquid film are numerically studied by using the coupled level set and volume-of-fluid model. This three-dimensional model effectively predicts the evolution of crown and crater, which is validated qualitatively and quantitatively by comparing with experimental observations. Some interesting interface features during the collision and coalescence of crowns are revealed in the present simulations, such as the gas cavity, liquid crest, and air gap. In addition, the crater contour takes on different phases with time in the case of dual droplets impact. The evolution characteristics of crater contours in front view and side view have been summarized within a certain time period. Furthermore, the variations of the maximum crater radius in upstream, downstream, and lateral directions as time are quantitatively analyzed. It is found that in the circumferential direction of the crater, the radial kinetic energy of the liquid decreases gradually from the upstream to the downstream direction. This research establishes a foundation for industrial and agricultural applications involving droplet impact.