Berkeley Fluids Seminar

University of California, Berkeley

Bring your lunch and enjoy learning about fluids!

Wednesday, February 21, 2018

12:00-13:00, HP Auditorium, Soda Hall

Prof. Leonardo Gordillo (Universidad de Santiago de Chile)

Drop-impact dynamics on solid surfaces: Evolution of impact force



Abstract: In this talk, I will give an overview of our latest advances in understanding the dynamics of drop impacts on dry solid surfaces. By synchronising high-speed photography with fast force sensing, we simultaneously measured the temporal evolution of the shape and impact force of impacting drops over a wide range of Reynolds numbers (Re). At high Re, the early-time evolution of impact force follows a square-root scaling. This observation provides direct evidence on the existence of upward propagating self-similar structures during the initial impact of liquid drops. At lower-Re impact, viscous forces gradually set in and the early-time scaling of the impact force of viscous drops changes. We used an analytical perturbation method to study this process that successfully predicts the quantitative increase of the maximum impact force with decreasing Re. This results provides a solid basis to understand the temporal evolution of impact forces across the inertial and viscous regimes and sheds new light on the self-similar dynamics during drop impact.



Bio: Dr. Leonardo Gordillo is an Assistant Professor in Physics at Universidad de Santiago de Chile. He got his PhD at Universidad de Chile working with Prof. N. Mujica on hydrodynamics of solitons in a quasi-one dimensional free surface. He has done his postoctoral research at Laboratoire de Matière et Systèmes Complexes at Université Paris Diderot and later in Prof. Cheng's group in the Chemical Engineering and Material Department at University of Minnesota. His research interests are Faraday waves, tsunamis, drop impact, boundary layers, acoustic streaming, and granular flows.





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