scholarly journals Analyse numérique du régime THD dans un patin échelon

2007 ◽  
pp. 683-701
Author(s):  
Mihai B. Dobrica ◽  
Michel Fillon
Keyword(s):  
Stokes Equations ◽  
Fluid Film ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Discontinuity Line ◽  
Discontinuous Flow ◽  
Model Based ◽  
Simple Geometry ◽  
Finite Differences Method ◽  
Film Lubrication

A lack of thermohydrodynamic (THD) models adapted to discontinuous fluid film geometries can be noted in the lubrication-related literature. The finite differences method, largely used in THD analysis, cannot be easily applied to discontinuous flow domains. This article proposes two finite volumes based models, suitable for discontinuous domains. The first model, based on Reynolds generalized equation, lacks in accuracy near the discontinuity line, but gains in computing speed. The second model, based on Navier-Stokes equations, is more accurate but also significantly more demanding in terms of computing requirements. The two models are applied and compared on the simple geometry of a bi-dimensional Rayleigh step bearing. Different configurations are analyzed, allowing the validation of the Reynolds model for most of the cases encountered in fluid film lubrication.

A Lattice-Boltzmann Approach to Fluid Film Lubrication

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Bogdan R. Kucinschi ◽  
Abdollah A. Afjeh
Keyword(s):  
Lattice Boltzmann ◽  
Stokes Equations ◽  
Fluid Film ◽  
Navier Stokes ◽  
Time Model ◽  
Navier Stokes Equations ◽  
Wall Boundary Conditions ◽  
Multiple Relaxation Time ◽  
Film Lubrication ◽  
Fluid Film Lubrication

This paper deals with the application of the lattice-Boltzmann method (LBM) to fluid-film lubrication. Compared with the traditional computational approach in lubrication (based on Reynolds equation), LBM does not neglect inertia forces. The implementation of LBM is less demanding than that of the Navier–Stokes solvers for complex geometric configurations. Various wall boundary conditions, as well as the multiple relaxation time model, are discussed. Bearing cavitation is approached in a simplified manner. The LBM solutions for two classic configurations are compared with the corresponding analytic and numeric solutions of the Reynolds or Navier–Stokes equations. The LBM results were satisfactory for the investigated cases.

Dynamical Study of a Molten Boundary Layer Ejected by Laminar Gas Flow

2014 ◽  
Vol 348 ◽  
pp. 88-93 ◽  
Author(s):  
S. Aggoune ◽  
El Hachemi Amara
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Gas Flow ◽  
Stokes Equations ◽  
Gas Jet ◽  
Navier Stokes ◽  
Dynamical Study ◽  
Navier Stokes Equations ◽  
Finite Differences Method ◽  
Layer Increase

We consider in the present work the fusion laser cutting of stainless steel sheets under a nitrogen laminar gas jet. The molten metal is treated as a laminar and steady viscous incompressible fluid. The mathematical model describing our problem is set in terms of Navier-Stokes equations, solved numerically using the finite differences method, where the effect of the gas jet velocity on the molten boundary layer is considered. The generated shear stress occurring on the gas-liquid interface and its contribution in the momentum is carried out, and it is found that when the skin friction and the shear stress decrease, the thickness and the velocity at the edge of the molten boundary layer increase along the kerf surface. The layer thickness reduces when the assisting gas velocity is increased.

scholarly journals Instability of inclined fluid-film flow with substrate filtration

2021 ◽  
Author(s):  
Hom N. Kandel
Keyword(s):  
Stokes Equations ◽  
Nonlinear Effects ◽  
Fluid Film ◽  
Navier Stokes ◽  
Neutral Stability ◽  
Fluid Films ◽  
Navier Stokes Equations ◽  
Gravity Driven ◽  
The Stability ◽  
Natural Settings

Gravity-driven flows of thin fluid films with a free surface along a porous substrate occur in many important circumstances found in industry and natural settings. In this thesis a model for such flows is derived by coupling the Navier-Stokes equations governing the clear flow in the fluid film with Darcy's law for the filtration of fluid through the porous medium. A linear stability analysis is conducted and the effect of various parameters on the state of neutral stability is investigated. A simplified model is developed by reducing the dimensionality of the problem, which is then employed in order to determine the nonlinear effects on the stability of the equilibrium flow.

A Finite Element Analysis of the Navier-Stokes Equations Applied to High Speed Thin Film Lubrication

1987 ◽  
Vol 109 (1) ◽  
pp. 71-76 ◽  
Author(s):  
J. O. Medwell ◽  
D. T. Gethin ◽  
C. Taylor
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
The Finite Element Method ◽  
Thin Film Lubrication ◽  
Element Analysis ◽  
Navier Stokes Equations ◽  
Film Lubrication

The performance of a cylindrical bore bearing fed by two axial grooves orthogonal to the load line is analyzed by solving the Navier-Stokes equations using the finite element method. This produces detailed information about the three-dimensional velocity and pressure field within the hydrodynamic film. It is also shown that the method may be applied to long bearing geometries where recirculatory flows occur and in which the governing equations are elliptic. As expected the analysis confirms that lubricant inertia does not affect bearing performance significantly.

Flow Over an Oscillating Plate With Suction or With an Intermediate Film: Two Exact Solutions of the Navier-Stokes Equations

1971 ◽  
Vol 38 (1) ◽  
pp. 262-265
Author(s):  
W. R. Debler ◽  
R. D. Montgomery
Keyword(s):  
Boundary Layer ◽  
Exact Solutions ◽  
Stokes Equations ◽  
Power Input ◽  
Fluid Film ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Oscillating Plate

The effect on the boundary layer of uniform blowing and suction across an oscillating plane, and the power input are determined. The change in power that is needed to oscillate a plate in an infinite fluid when an intermediate fluid film is present is also found.

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