Abstract
Droplet impacts on solid surfaces are key elements in technical applications, such as semiconductor cleaning, rapid spray cooling and ink-jet printing. There exist varieties of physical parameters proposed that control the droplet impact although they are not thoroughly explored; hence, dynamics of the droplet after the impact are yet fully understood. In this study, we experimentally observed the high-speed droplet impact on acrylic surfaces in a vacuum chamber with a high-speed photography, in order to clarify the effects of both the ambient gas pressure around the droplet and the impact velocity. The results show that the splash does not occur under the reduced ambient gas pressure even when the impact velocity becomes much higher than in the conventional experiments, in the range of the present experimental conditions.
