2025/01/28 by Stéphane Poulain, Timo Koch, Poulain, Stephane +5 · 2 citations
Engineering · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Heat Transfer #Fluid Dynamics and Mixing #Soft Condensed Matter (cond-mat.soft) #Sports Dynamics and Biomechanics
paper · pdf · doi:10.48550/arxiv.2501.17080
openalex publication_date 2025/01/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/03
Inspired by recent experimental observations of a harmonically excited elastic foil hovering near a wall while supporting substantial weight, we develop a theoretical framework that describes the underlying physical effects. Using elastohydrodynamic lubrication theory, we quantify how the dynamic deformation of the soft foil couples to the viscous fluid flow in the intervening gap. Our analysis shows that the soft foil rectifies the reversible forcing, breaking time-reversal symmetry; the relative spatial support of the forcing determines whether the sheet is attracted to or repelled from the wall. A simple scaling law predicts the time-averaged equilibrium hovering height and the maximum weight the sheet can sustain before detaching from the surface. Numerical simulations of the governing equation corroborate our theoretical predictions, are in qualitative agreement with experiments, and might explain the behavior of organisms while providing design principles for soft robotics.