Numerical Investigation of Multiple High-Speed Droplets Impacting a Rigid Surface

In this study, the complex interactions and resulting loads on high-speed objects moving through droplet clouds in the atmosphere, a phenomenon that remains poorly understood, is investigated. The focus is on the impacts of two water droplets in close proximity to each other onto a rigid wall. Using a second-order accurate method with adaptive mesh refinement (AMR) and a consistent, conservative Phase-Field method, this research numerically examines the role of spacing and size ratio on the impact of two Mach 4 droplets on a rigid wall in two dimensions. Results show that lateral jets form along the wall during the impact and eventually impinge upon each other creating a water-hammer effect. For droplets sufficiently close to each other, this pressure is greater than the impact pressure of each droplet, or the pressure due to air compression along the wall. This research enhances the understanding of surface loads from the interaction of high-speed objects with collections of liquid droplets.