title: Self-sustained lift and low friction via soft lubrication.
abstract: Relative motion between soft wet solids arises in a number of applications in natural and artificial settings, and invariably couples elastic deformation fluid flow. We explore this in a minimal setting by considering a fluid-immersed negatively buoyant cylinder moving along a soft inclined wall. Our experiments show that there is an emergent robust steady-state sliding regime of the cylinder with an effective friction that is significantly reduced relative to that of rigid fluid-lubricated contacts. A simple scaling approach that couples the cylinder-induced flow to substrate deformation allows us to explain the elastohydrodynamic lift that underlies the self-sustained lubricated motion of the cylinder, consistent with recent theoretical predictions. Our results suggest an explanation for a range of effects such as reduced wear in animal joints and long-runout landslides, and can be couched as a design principle for low-friction interfaces.
authors.affiliation: Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138;
authors.forename: Baudouin
authors.initials: B
authors.lastname: Saintyves
authors.affiliation: Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138; Department de Physique, École Normale Supérieure, Université de Recherche Paris Sciences et Lettres, 75005 Paris, France;
authors.forename: Theo
authors.initials: T
authors.lastname: Jules
authors.affiliation: Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138; Laboratoire de Physico-Chimie Théorique, UMR CNRS 7083 Gulliver, École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris, Université de Recherche Paris Sciences et Lettres, 75005 Paris, France;
authors.forename: Thomas
authors.initials: T
authors.lastname: Salez
authors.affiliation: Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138; Department of Physics, Harvard University, Cambridge, MA 02138; Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138; Kavli Institute for Bionano Science and Technology, Harvard University, Cambridge, MA 02138 lm@seas.harvard.edu.
authors.forename: L
authors.initials: L
authors.lastname: Mahadevan
keywords: elastohydrodynamics; friction; lubrication; soft contact