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Lubrication Transition and Viscous Adhesion
The interplay between elastic and fluid stresses arises in a wide range of physical systems, often leading to rich and non-trivial dynamics. In this seminar, we explore two such scenarios in thin-film flows, with applications to friction and adhesion.
In the first part, we focus on the lubrication transition—the shift between frictional and lubricated contact. We show experimentally that introducing viscoelastic stresses via dilute polymer solutions significantly alters or delays this transition. Similarly,
in dense granular flows, coating particles with a soft polymeric layer dramatically modifies their frictional behaviour. Motivated by these findings, we propose a unified mean-field model that captures the essential features of the lubrication transition across
both systems.
In the second part, we investigate viscous adhesion—the effective adhesion between two soft surfaces separated by a thin liquid film. Despite the absence of direct contact, we show that the elastic response to viscous suction leads to an “adhesion without contact”
mechanism. This process exhibits striking analogies with classical JKR adhesion, yet arises purely from fluid-structure interactions.