The turbulence beneath and along the free surface of water bodies determines transport properties at the global scale, e.g., the uptake of CO2 and the spreading of floating plastics in oceans, rivers, and lakes. Even in the seemingly simple case of a flat surface, the dynamics are deceptively complex and predicting the fundamental flow properties is not trivial. In the presence of large surface deformations, the problem is further complicated by the mutual transfer of energy between the bulk flow and gravity-capillary waves, and the interaction among the latter. When wind applies shear to the surface and builds waves, these exchange energy with both the mean and the turbulent flow fields.
Filippo Coletti,
ETH Zurich
In this talk, I will touch upon fundamental aspects of free-surface turbulence, ranging from cases in which the bulk flow barely deforms the surface; to cases where it corrugates it dynamically; to cases in which turbulence is created and modulated by wind-driven waves on the edge of breaking. Those flows are investigated with a suite of experimental facilities and leveraging high-resolution imaging, to improve our predictive understanding of the two-way coupling between the surface and the turbulence underneath.
Filippo Coletti is Professor of Experimental Fluid Dynamics at ETH Zurich, where he has been since 2020. Previously he was McKnight Land-Grant Associate Professor of Aerospace Engineering & Mechanics at the University of Minnesota, which he joined in 2014, and held visiting professor positions in IMFT Toulouse and ENS Lyon. He performed his doctoral studies at the von Karman Institute for Fluid Dynamics and at the University of Stuttgart, where he obtained his PhD in 2010, and was postdoctoral fellow at Stanford University between 2011 and 2013. He received the NSF CAREER award in 2015 and the ERC Consolidator grant in 2022. In 2025 he was elected fellow of the American Physical Society, Division Fluid Dynamics. He founded and co-organizes the Fluid Mechanics Tour of the Alps, an itinerant seminar series featuring the world’s top fluid mechanicians. His research interests focus on multiphase flows, which he studies with a range of experimental approaches and with applications to environmental, biomedical, and industrial problems.