Analyses of Lubricant Deformation Caused by Gas Stresses and Surface Tension

Surface deformations of thin lubricant films on solid surfaces were studied through numerical simulations of the long-wave equation, taking into account surface tension, applied gas stresses, and disjoining pressure. We focused on transient behaviors of three-dimensional deformations caused by nonuniform gas pressure, gas shear stress, and surface tension. The deformed surface shapes depend on distribution shapes of the nonuniform surface forces, and the constraint of lubricant mass conservation induces secondary deformations. Deformation in the vertical direction decelerates with time due to the suppression effect of the disjoining and Laplace pressures.