INTRODUCTION The ordinary hydrodynamic bearings have been replaced by the hydrostatic bearings in the application of machine tools in recent years. For the hydrodynamic bearings, the journal and the bearing surface are separated by the sliding action with a wedge pressure-generating mechanism to develop a pressure within the bearing. It has advantages of simple structure and cheap cost. However...

The hydrodynamic force experienced by a spherical-cap drop moving on a solid surface is obtained from two approximate analytical solutions and used to predict the quasi-steady speed of the drop in a wettability gradient. One solution is based on approximation of the shape of the drop as a collection of wedges, and the other is based on lubrication theory. Also, asymptotic results from both appr...

A theoretical investigation has been made of core-annular flow: the flow of a high-viscosity liquid core surrounded by a low-viscosity annular liquid layer through a horizontal pipe. Special attention is paid to the question how the buoyancy force on the core, caused by a possible density difference between the core and the annular layer, is counterbalanced. From earlier studies it is known tha...

Ensuring effective lubrication between sliding surfaces is one of the challenges in the field of tribology. In addition to the conventional parameters like speed, load, contact geometry and material parameters, the surface texture also influences the coefficient of friction. In the present investigation, the effect of surface texture on coefficient of friction under boundary lubricated conditio...

In this paper are presented the influences of the adhesion forces occurring in hyperbolic micro contact on the oil velocity and friction forces in hyper bolic micro bearing gap. Here are elaborated the dependences between adhesive forces and oil dynamic viscosity in super t hin boundary layer and in fluences of adhesive forces on the oil velocities and friction forces in microand nano-scale ari...

Diameter and diametral clearance of the bearing surfaces of metal-on-metal hip implants and structural supports have been recognised as key factors to reduce the dry contact and hydrodynamic pressures and improve lubrication performance. On the other hand, application of aspherical bearing surfaces can also significantly affect the contact mechanics and lubrication performance by changing the r...