, S2: (a) The non-dimensional lift force as a function of distance from the surface transition point (x t ). For non-dimensional slip length L < 10 ?2 the standard definition for contact length (l c ) is a reasonable approximation (highlighted with the inset). For larger slip lengths the force is non-negligible with x t /l c > 1. (b) Transition length as a function of non-dimensional slip

D. Jeffery, Y. Onishi, and Q. , J. Mech. Appl. Math, vol.34, p.129, 1981.

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