Numerical study of oblique droplet impact on a liquid film

Abstract

The dynamic characteristics of droplet obliquely impact on a liquid film are investigated numerically by using the Coupled Level Set and Volume of Fluid method (CLSVOF), with the impact angle ranging from 0° to 60°. The influence factors as film thickness and Weber number on the splashing formation and the crown evolution are also systematically investigated. Results showed that the crown radius on the behind side of the advancing droplet decreases as the impact angle increases, while the crown radius on the front side of the advancing droplet appears to be an opposite trend. Furthermore, the crown diameter is almost unchanged when the impact angle increases from 30° to 45°. However, when the impact angle increases to 60°, the crown lamella on the front side of the advancing droplet is completely suppressed. It is found that the crown height does not linearly change with the film thickness. With an increase in the film thickness, the right crown height first increases and then decreases, indicating the presence of a critical film thickness under the studied conditions. An increase in Weber number results in a transition from non-splashing to partial splashing and even to entire splashing.