Couple stress magneto-hydrodynamic squeeze film lubrication of rough journal bearings

Purpose This study aims to investigate anisotropic rough-surface finite journal bearings under squeezing conditions, lubricated by couple stress fluids, while accounting for the magneto-hydrodynamic (MHD) effects. Design/methodology/approach Stokes’ theory is applied to describe the flow behavior of couple stress lubricants. The homogenization theory is used to model the anisotropic surface roughness. Based on the combination of these two theories, a new expression of the homogenized Reynolds equation is obtained. This equation is solved by a numerical differentiation approach to determine the pressure film, which is then used to calculate the load-carrying capacity and the squeeze time. Findings The obtained results are analyzed for some values of the couple stress parameter, Hartmann number and the relative amplitude of anisotropic roughness. In particular, an increase in the relative amplitude of anisotropic roughness augments the load-carrying capacity and squeeze time. Originality/value The novelty of this study lies in its consideration of anisotropic surface roughness and MHD couple stress impacts on journal bearings’ performance under squeezing conditions. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2025-0155/