Simulation of Lubricant Behavior by Using the Particle Method

Lubricant behavior within a head-disk clearance in recent hard disk drives was simulated by using a particle method, which is based on continuum dynamics. The lubricant was simulated as a group of particles. The surface tension and the wall-adhesion models used in the particle method were verified before applying the particle method to the lubricant behavior simulation first. That is, simple benchmark problems like liquid-droplet deformations under unbalanced surface tension and wall adhesion force were used to confirm the accuracy of the models. In the lubricant simulation, the effects of viscous stress and surface tension on the lubricant behavior were studied. The study found that viscous stress is the dominant factor in comparison with surface tension on bulk condition of viscosity; that is, the lubricant bridge is deformed by the viscous stress, not by the surface tension.