This contribution deals with a self-consistent description of time-mean turbulent lubricant flow, i.e. flow through a wedge-shaped gap confined by counter-sliding solid surfaces. The methods adopted are matched asymptotic expansions, where the slenderness or aspect ratio of the gap and the accordingly defined Reynolds number represent the perturbation parameters. As a remarkable result, a load-...

In this paper, an investigation of hydrodynamic performance for journal bearing lubricated by thin film is performed by three-dimensional CFD (computational fluid dynamic). Two regimes, i.e. laminar and turbulent regimes are of main interest. The sliding velocity was varied from 3000, 5000 and 10000. The numerical simulation shows that the velocity magnitude of the journal has a strong effect o...

The accepted theory of joint lubrication is that of MacConaill (1932), who assembled arguments to show that it was an example of hydrodynamic or full-film lubrication. The principal argument in applying the hydrodynamic theory to animal joints was the anatomical fact that in joints the curvatures of articulating surfaces are not completely congruous throughout their whole arc of movement. It wa...

Hydrodynamic performance of gas microbearings, fabricated with deep X-ray lithography and electroplating, will be presented in this article. Static performance in terms of load parameters and attitude angles was calculated using Molecular Gas Lubrication (MGL) theory. Threshold speed and allowable rotor mass were calculated to investigate safe operating conditions of the fabricated gas microbea...

Viscosity has always been a critical property of lubricants. It is the source of the hydrodynamic lubrication that separates lubricated surfaces moving past one another under pressure and thus is a major factor in reducing wear. On the other hand, viscosity is also a form of friction – viscous friction – and, as it absorbs energy, viscosity reduces the efficiency of the engine even as it protec...

We consider the Elrod–Adams model extending the classical lubrication Reynolds equation to the case of the possible presence of a cavitation region. We show that the behaviour of the pressure and saturation depends crucially on the behaviour of the separation h(t, x, y) among the two surfaces. In particular, we exhibit some simple formulations for which we prove (rigorously) that a cavitation r...