Rate-dependent slip of Newtonian liquid at smooth surfaces.
Newtonian fluids were placed between molecularly smooth surfaces whose spacing was vibrated at spacings where the fluid responded as a continuum. Hydrodynamic forces agreed with predictions from the no-slip boundary condition only provided that flow rate (peak velocity normalized by spacing) was low, but implied partial slip when it exceeded a critical level, different in different systems, correlated with contact angle (surface wettability). With increasing flow rate and partially wetted surfaces, hydrodynamic forces became up to 2-4 orders of magnitude less than expected by assuming the no-slip boundary condition that is commonly stated in textbooks.
Zhu
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Department of Materials Science and Engineering, University of Illinois, Urbana, 61801, USA.
Granick
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