An experimental study of the lubrication theory for highly compressible porous media, with and without lateral leakage

In this paper, we report a comprehensive, experimental study to examine the lubrication theory for highly compressible porous media. It is inspired by the frictionless motion of red cells in a tightly fitting capillary and a human skiing/snowboarding. A novel experimental setup was developed where lubrication pressure generated in a soft porous layer was measured as planar board glides over it. Both laterally confined (1-D) and unconfined (2-D) situations were examined. The results excellently agree with the theory by Feng & Weinbaum (J. Fluid Mech. 422 (2000), pp. 281-317) and Wu & Sun (Med. Sci. Sports Exerc. 43 (2011), pp. 1955-1963). The paper demonstrates the significant potential of applying soft porous media in lubrication with tremendously enhanced hydrodynamic lift.