Rate-dependent slip of Newtonian liquid at smooth surfaces

Phys Rev Lett. 2001 Aug 27;87(9):096105. doi: 10.1103/PhysRevLett.87.096105. Epub 2001 Aug 10.


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.