Stokes Roughness Effects on Hydrodynamic Lubrication : 2nd Report, In Slip Flow Conditions

the effects of changing roughness on the flow structure in the bends

flow in natural river bends is a complex and turbulent phenomenon which affects the scour and sedimentations and causes an irregular bed topography on the bed. for the reason, the flow hydralics and the parameters which affect the flow to be studied and understand. in this study the effect of bed and wall roughness using the software fluent discussed in a sharp 90-degree flume bend with 40.3cm ...

Micro-Roughness Effects in (Elasto)Hydrodynamic Lubrication Including a Mass-Flow Preserving Cavitation Model

An average Reynolds equation is proposed for predicting the effects of deterministic periodic roughness, taking JFO mass flow preserving cavitation model and elastohydrodynamic effects into account. For this, the asymptotic model is based upon double scale analysis approach. The average Reynolds equation can be used both for microscopic interasperity cavitation and macroscopic one. The validity...

Pjasa Surface Roughness Effects in Hydrodynamic Lubrication: the Flow Factor Method

Random-roughness hydrodynamic boundary conditions.

We report results of lattice Boltzmann simulations of a high-speed drainage of liquid films squeezed between a smooth sphere and a randomly rough plane. A significant decrease in the hydrodynamic resistance force as compared with that predicted for two smooth surfaces is observed. However, this force reduction does not represent slippage. The computed force is exactly the same as that between e...

On Turbulence in Hydrodynamic Lubrication

The contribution deals with a self-consistent description of time-mean turbulent lubricant flow, i.e. flow through a wedgeshaped 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 finding, a load-b...