A fluid lubrication analysis including negative pressure using a physically consistent particle method

In recent years, particle methods, which are good for moving boundary problems, have become an effective approach to understand and predict flows in complex geometry, such as lubrication behaviors in rolling bearings. This study adopted a physically consistent particle method, i.e., the moving particle hydrodynamics for incompressible flows (MPH-I) method. For capturing the free surface flows in lubrication, a surface tension model was included. In order to maintain the physical consistency in the MPH-I method, the surface tension model expressed with the two density potentials, which are cohesive pressure potential (CPP) and density gradient potential (DGP), was adopted. The MPH-I method with the two-potential-based surface tension model enabled to handle negative pressure and nearly incompressible flow with very large bulk modulus. In fact, the MPH-I method could successfully reproduce fundamental pressure generation effects in the fluid film lubrication, i.e., the wedge film and squeeze film effects. Furthermore, the computed lubrication pressure agreed well with the experimental results and the classic prediction with Reynolds equation. This implies that the present numerical method was validated under the fluid film lubrication problems.