This CAREER will advance the understanding of flows involving liquid and gas mixtures that form bubbles, droplets, and sprays in nature and technology. These flows appear in ocean waves, clouds, rainfall, and lungs, as well as in chemical reactors, pipelines, and energy systems. Predicting how bubbles and droplets form, merge, and break apart is these flows is challenging. These phenomena are influenced by fast and complex interactions that occur across a wide range of sizes and speeds. They are not well represented in current computer models. This project will develop improved tools for simulating these flows by focusing on how the surfaces between gas and liquid stretch, wrinkle, and change over time. Better simulation tools will benefit scientific discovery and support advances in national priority areas such as energy production, chemical processing, weather forecasting, transportation, aerospace, and naval systems. The project will also help build a skilled engineering workforce through integrated education and outreach efforts. High school, undergraduate, and graduate students will participate in hands-on research and computational training, strengthening pathways into science and engineering careers. This award will develop a predictive simulation framework for gas-liquid flows characterized by complex interfacial dynamics. The research will investigate how interfacial surface area is generated and destroyed during surface wrinkling, breakup, and coalescence, and how these topological changes influence the exchange of mass, momentum, and energy across the interface. The project will introduce a modeling framework that treats interfacial area as a dynamic transported quantity and develops multiscale models grounded in first-principles analysis and high-resolution numerical simulations. The work will combine three components: (1) quantitative assessment of multiscale interfacial geometry; (2) development of sub-resolution models that capture interfacial to