Steep wave fronts tend to develop in many regimes of lubricated, slipping flows in which waves appear. Problems of slip, spurt, fracture and extrudate distortion can be framed in terms of lubrication theory with paradigms arising from the lubrication of heavy oil with water for some problems and concepts from the theory of boundary lubrication for others. In water lubricated pipelines, high pre...

The mathematical and computational modeling of the lubricated contact between bearing surfaces is presented to analyze sliding friction using a realistic 3D model on microscopic scale. fluid–structure interaction evaluates effects lubricant film thickness in hydrodynamic mixed lubrication regimes. Higher pressures are seen at peaks asperities, especially during lubrication, which fluid volume s...

We have measured the normal, lateral and hydrodynamic forces that act between polymer-brush-bearing surfaces immersed in a good-solvent medium, both when stationary and when in motion with respect to each other. At low sliding velocities we find a very marked decrease in the frictional force between the surfaces, an effect interpreted in terms of a fluid interfacial layer resulting from the non...

An elastically deformable bearing ring is investigated. The piezo-actuated shaping of the elastic as well journal motion are coupled and determine height lubrication gap which takes a crucial part in theory hydrodynamic lubrication. influence active-dynamic on rotor dynamic behaviour has been investigated [1], especially for two-lobe bearing. present investigations aiming at active-static ring,...

Atomistic molecular dynamics simulations reveal the formation of nanojets with velocities up to 400 meters per second, created by pressurized injection of fluid propane through nanoscale convergent gold nozzles with heating or coating of the nozzle exterior surface to prevent formation of thick blocking films. The atomistic description is related to continuum hydrodynamic modeling through the d...

The problem of the moving contact line is described and the singularity that arises after application of the classic hydrodynamic model is discussed. The central experimental observation that the motion is rolling is confirmed by a simple experiment. Subsequently, some of the various methods that have been developed to resolve the difficulty are briefly described. In addition, the lubrication e...

Surfaces can be slippery or sticky depending on surface chemistry and roughness. We demonstrate in atomistic simulations that regular and random slip patterns on a surface lead to pressure excursions within a lubricated contact that increase quadratically with decreasing contact separation. This is captured well by a simple hydrodynamic model including wall slip. We predict with this model that...

Thermodynamic and dynamic analyses of a variable speed reciprocating compressor have been conducted to investigate performance changes and some data related to the reliability problems such as valve velocity, PV value, bearing loci, Sommerfeld number, minimum film thickness etc. The first law of thermodynamics, continuity equations, valve dynamic equations and Helmholtz resonator method were us...