Impact force and pressure distribution of droplets impacting non-wetting surfaces

Non-wetting surfaces have been extensively applied and studied due to their distinctive droplet impact dynamics. However, there is still a lack of studies on the droplet impact force and surface pressure distribution on the non-wetting surfaces. The impact process of a droplet on the non-wetting surface is systematically simulated using the volume-of-fluid method with a high-resolution grid, taking into account the effects of the Weber number (We) and the Ohnesorge number (Oh). The numerical results indicate that the droplet impact force exhibits a bimodal nature, which arises from the changes in the surface pressure distribution during the impact process. Meanwhile, in contrast to the bouncing process, tremendous pressure appears at the center of the droplet collision at the instant of jet generation. Most notably, the maximum pressure of the surface rapidly decays from more than ten times the dynamic pressure during the early stages of the droplet impact, while the location of the maximum pressure moves supersonically in the radial direction. These findings will deepen the understanding of droplet erosion and surface moisture resistance properties.