Couple-stress squeeze ®lms between porous rectangular plates

Abstract: In this paper, the squeeze-®lm lubrication theory between two isotropic porous rectangular plates has been advanced to analyse the effects of couple stresses arising due to the presence of microstructure additives in the lubricant, using the Stokes theory of couple-stress ¯uids. The most general form of the modi®ed Reynolds equation is derived for the squeeze-®lm lubrication of the porous rectangular plates by taking into account of the velocity slip at the porous interface. An eigentype of expression is obtained for the squeeze-®lm pressure. The effects of the isotropic permeability, the couple stresses and the velocity slip parameters on the characteristics of the squeeze-®lm lubrication are discussed. A signi®cant increase in the load-carrying capacity and the delayed squeeze-®lm time are observed for the couple-stress ¯uids in comparison with Newtonian ¯uids