Hovering of an actively driven fluid-lubricated foil

Fuente: arXiv
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Hauptverfasser: Poulain, Stephane, Koch, Timo, Mahadevan, L., Carlson, Andreas
Format: Preprint
Veröffentlicht: 2025
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author Poulain, Stephane
Koch, Timo
Mahadevan, L.
Carlson, Andreas
author_facet Poulain, Stephane
Koch, Timo
Mahadevan, L.
Carlson, Andreas
contents 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.
format Preprint
id arxiv_https___arxiv_org_abs_2501_17080
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hovering of an actively driven fluid-lubricated foil
Poulain, Stephane
Koch, Timo
Mahadevan, L.
Carlson, Andreas
Fluid Dynamics
Soft Condensed Matter
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.
title Hovering of an actively driven fluid-lubricated foil
topic Fluid Dynamics
Soft Condensed Matter
url https://arxiv.org/abs/2501.17080