I. INTRODUCTION
It is almost 100 years since Reynolds 1 published his
analysis of hydrodynamic lubrication due to a thin macro-
scopic film ofliquid confined between two moving solid sur-
faces. This theory is based on a simplification of the Navier-
Stokes equations of continuum hydrodynamics by exploit-
ing the special geometry of thin films. The utility of this
theory still stands today and many extensions and applica-
tions of the original analysis may be found in text books on
hydrodynamic lubrication theory.2