Can a viscous liquid flowing over a hypothetical perfectly smooth surface exert viscous stresses on the surface? Can the viscosity of a fluid describe interactions between the fluid and some other solid over which it flows? Also, in the above case will the fluid experience a no-slip condition?
Fluid Dynamics – Viscous Flow Over a Perfectly Smooth Surface
boundary conditionsflowfluid dynamicsviscosity
Best Answer
For everyday conditions, fluids, and surfaces, the no-slip condition is always observed.
For fluids that wet the static surface well, the intermolecular forces of adhesion will enforce the no-slip condition even if the static surface is completely smooth (on microscopic scales).
This means that with fluid velocity = zero at the wall, shear stresses will propagate into the stream away from the wall via viscosity coupling between infinitesimal layers of fluid that are in contact. So the surface will experience a shear stress- and the more viscous the liquid, the greater the stresses can become.