Eur. Phys. J. E (2020) 43: 9
https://doi.org/10.1140/epje/i2020-11933-4

Regular Article

Lubricated sliding friction: Role of interfacial fluid slip and surface roughness

¹ Sanofi, 13, quai Jules Guesde, BP 14-94403, Vitry-sur-Seine Cedex, France
² PGI-1, FZ Jülich, Jülich, Germany
³ MultiscaleConsulting, Wolfshovener str 2, 52428, Jülich, Germany
⁴ DII, Università del Salento, Lecce, Italy

^* e-mail: b.persson@fz-juelich.de

Received: 30 July 2019
Accepted: 24 January 2020
Published online: 10 February 2020

Abstract

We derive approximate mean field equations for the fluid flow between elastic solids with randomly rough surfaces including interfacial fluid slip and shear thinning. We present numerical results for the fluid flow and friction factors for realistic systems, in particular, we consider the case of an elastic cylinder with random surface roughness in relative sliding contact with a flat rigid (low-energy) counter-surface. We present experimental data for the sliding friction between rubber stoppers and glass barrels lubricated with baked-on silicone oil. We find that the frictional shear stress acting in the rubber asperity contact regions is nearly velocity independent for velocities in the 10-1000μm/s range, and very small MPa, while for bare glass in silicone oil is much larger and velocity dependent.