The dynamics of droplet impact, such as the bouncing of raindrops, are frequently encountered in nature. From an engineering standpoint, while traditionally relevant to applications such as spray coating and painting, their importance has significantly expanded in recent years to encompass high-precision processes in semiconductor manufacturing—such as etching, coating, and cleaning—as well as advanced additive manufacturing technologies like 3D printing, where precise fluid delivery is critical. Droplet-wall interactions are fundamentally governed by density and viscosity contrasts, as well as complex interfacial phenomena including surface tension and contact angle dynamics. These processes occur over extremely small spatial and temporal scales, making it experimentally challenging to capture the underlying physics with experiment. As a result, numerical simulations have become an alternative tool for investigating these phenomena in detail.
Accurate interface tracking is a crucial component of accurate numerical simulations. Both direct interface Front Tracking and indirect interface-capturing methods including Volume-of-Fluid (VOF), Level Set, and Lattice Boltzmann methods have been widely employed. Initial studies on droplet impact primarily focused on simplified scenarios such as droplets impact on flat surfaces, with particular attention to the maximum spreading diameter and the associated time scale. More recently, the scope of research has expanded to include curved and textured surfaces, requiring more sophisticated modeling of interfacial phenomena such as contact angle hysteresis. The consideration of surfactant effects has made the problem significantly more complex. In parallel, there has been growing interest in non-Newtonian and viscoelastic fluids, extending the applicability of these models to a broader range of industrial and biological contexts.
This presentation focuses on the development of accurate interface-tracking techniques tailored to simulate droplet impact on complex solid geometries. Special emphasis is given to advanced contact models capable of robustly capturing surface interactions. In addition, the incorporation of various auxiliary models is discussed to account for intricate interfacial behaviors such as Marangoni, surfactant, non-Newtonian, viscoelastic, phase change effect, etc., with the ultimate goal of enhancing the predictive capability of direct numerical simulations in realistic multiphase flow scenarios.

暂无