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arXiv · 2306.17696

Anomalous Scaling for Hydrodynamic Lubrication of Conformal Surfaces

James A. Richards·Patrick B. Warren·Daniel J. M. Hodgson·Alex Lips·Wilson C. K. Poon
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Abstract

The hydrodynamic regime of the Stribeck curve giving the friction coefficient $\mu$ as a function of the dimensionless relative sliding speed (the Sommerfeld number, $S$) of two contacting non-conformal surfaces is usually considered trivial, with $\mu \sim S$. We predict that for conformal surfaces contacting over large areas, a combination of independent length scales gives rise to a universal power-law with a non-trivial exponent, $\mu\sim S^{2/3}$, for a thick lubrication film. Deviations as the film thins (decreasing $S$) may superficially resemble the onset of elastohydrodynamic lubrication, but are due to a crossover between hydrodynamic regimes. Our experiments as well as recent measurements of chocolate lubrication confirm these predictions.

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James A. Richards, Patrick B. Warren, Daniel J. M. Hodgson, Alex Lips, Wilson C. K. Poon. 2023-06-30. Anomalous Scaling for Hydrodynamic Lubrication of Conformal Surfaces. https://arxiv.org/abs/2306.17696

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