MAE 298 SEMINAR: Surface Tension in Engineering and Geophysical Flows - From Nonlinear Waves to Droplet Interactions

Abstract: Surface tension governs interfacial fluid dynamics in engineering applications and geophysical flows. Computing the surface tension force is challenging, as it requires a precise description of the fluid interface. The first part of this talk will be devoted to the role of surface tension in physical processes involving nonlinear wave dynamics. I will introduce a theoretical and numerical study of weakly nonlinear interactions of gravity-capillary waves in two-layer fluid systems, showing how surface tension can influence the strength of nonresonant interactions and give rise to a new type of resonant interaction. I will then present multiphase direct numerical simulations of strongly nonlinear breaking waves and quantify the bioluminescent light intensity emitted by oceanic microorganisms. The critical role of air bubbles in both the breaking-wave hydrodynamics and the bioluminescence process will be discussed. In the third part of this talk, I will highlight recent progress on the interaction between raindrops and a deep pool, including a new scaling law for the secondary droplets produced by direct raindrop–pool interactions, and how raindrop interactions influence the evolution of these droplets.

Bio: Xuanting Hao is an assistant professor affiliated with the Department of Mechanical and Aerospace Engineering and the Scripps Institution of Oceanography at the University of California, San Diego. His research focuses on small-scale geophysical flows at the atmosphere-ocean interface, leveraging physics-based and data-driven models supported by modern high-performance computing. Before joining UC San Diego, Hao was a visiting scholar at the University of Miami and a postdoctoral scholar at the University of Minnesota, where he also earned a Ph.D. in mechanical engineering.