Elastohydrodynamic lift at a soft wall

Heather S Davies (1) , Delphine Débarre (1) , Nouha El Amri (1) , Claude Verdier (1) , Ralf P Richter (2) , Lionel Bureau (1)

1 LIPhy - Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères]
2 University of Leeds

We study experimentally the motion of non-deformable microbeads in a linear shear flow close to a wall bearing a thin and soft polymer layer. Combining microfluidics and 3D optical tracking, we demonstrate that the steady-state bead/surface distance increases with the flow strength. Moreover, such lift is shown to result from flow-induced deformations of the layer, in quantitative agreement with theoretical predictions from elastohydrodynamics. This study thus provides the first experimental evidence of ``soft lubrication'' at play at small scale, in a system relevant {\it e.g.} to the physics of blood microcirculation.

Domaines: Matière Molle [cond-mat.soft]

Heather S Davies, Delphine Débarre, Nouha El Amri, Claude Verdier, Ralf P Richter, et al.. Elastohydrodynamic lift at a soft wall. Physical Review Letters, 2018, 120, pp.198001. ⟨10.1103/PhysRevLett.120.198001⟩. ⟨hal-01652253v2⟩