The exponent 2 given by equation agrees well with the power-law data presented in Figure \[maximum\] (right).

Comparison with experiments
---------------------------

Two comparisons with experimental results can now be given. First, we wish to comment on the general order of magnitude of the slip lengths obtained. For a review of the pressure-driven flow experiments in capillaries which report some degree of slip as summarized in the introduction, the reader is referred to [@LaugaStone].

The order of magnitude for the maximum slip lengths given by our mechanism (tens to hundreds of nanometers) are consistent with the slip lengths measured in the indirect pressure-driven slip experiments of [@Churaev; @Cheng; @Breuer]. Of course, the effect we report here does not directly apply to their pressure drop versus flow rate measurements, but the comparison shows that both effects are comparable in magnitude and therefore the apparent slip mechanism could have important consequences on experimental probing of the no-slip boundary condition.

We also wish to address specifically the experiment of Tretheway & Meinhart [@Meinhart] for which our study directly applies. The channels used in their experiment have height $2h=30~\mu$m and width $2w=300~\mu$m; the separation of scale $w\gg h$ allows us to approximate the flow by 