First Effects of Stokes Roughness on Hydrodynamic Lubrication

Considering the actual roughness dimensions as well as the typical dimensions of a hydrodynamically lubricating film, the Stokes equations are used to analyze the roughness effects. The surface profile is modeled by an ergodic, stationary random process. It is revealed that the roughness effects can be determined by three parameters; viz., the rms roughness, the correlation length, and the correlation wavelength. The present results are significantly different from those in the literature, where the Reynolds equation is used for analysis.