BurgersTour/ME lecture: Floating on Turbulence
Speaker
About this event
From marine litter to ice floes, natural bodies of water are often populated with floating objects spanning vast ranges of size, shape, and concentration. Predicting their behaviour requires understanding how turbulent water motion is altered by the presence of the free surface, and how the underlying turbulence influences the interfacial dynamics between the surface and the floating objects, as well as among interacting floaters. Even in the seemingly simple case where surface waves are negligible, the problem is rich in fascinating phenomena. This seminar presents a series of experiments conducted in flow facilities large and small, in which marginally buoyant particles (millimetric to centimetric, round and irregular, solid and deformable) float on turbulent water. For simplicity, the focus is primarily on two opposite limits. First, a dilute suspension of non-interacting discs significantly larger than the dissipative scales of turbulence is considered. These discs exhibit translational and rotational motions dictated by the local flow, coarse-grained at the scale of the particle. Second, dense suspensions of smaller spherical particles are considered. These form multiscale, percolating clusters bound by capillary forces, whose dynamics is well described by a population-balance framework. Finally, the seminar provides insights into the profoundly different behaviour exhibited by floating rods and oil droplets. Filippo Coletti is Professor of Experimental Fluid Dynamics at ETH Zurich, where he has been since 2020. Previously, he was McKnight Land-Grant Professor of Aerospace Engineering and Mechanics at the University of Minnesota, which he joined in 2014. He completed his doctoral studies at the Von Karman Institute for Fluid Dynamics and the University of Stuttgart, earning his PhD in 2010. He was subsequently a postdoctoral fellow at Stanford University from 2011 to 2013. He received the CAREER Award from the U.S. National Science Foundation in 2015 and an ERC Consolidator Grant from the European Research Council in 2022. He is a Fellow of the American Physical Society and an Associate Editor of the Journal of Fluid Mechanics. He founded and co-organizes the Fluid Mechanics Tour of the Alps, an itinerant seminar series featuring leading researchers in fluid mechanics. His research focuses on multiphase flows, which he investigates using a wide range of experimental techniques, with applications in environmental, biomedical, and industrial systems.
Host
