Combined Non-Newtonian and Viscous Shear Effects on Porous Squeeze Film Behavior

Nabhani, Mohamed; Khlifi, Mohamed El; Bou‐Saïd, Benyebka

doi:10.1080/10402004.2012.669030

Cited by 15 publications

(10 citation statements)

References 18 publications

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“…Moreover, the increasing in magnitude of the couple stress parameter (i.e. for larger chain lengths of the additives molecule) increases the values of W. This is in good agreement with the results from Elsharkawy and Alyaqout 25 for porous slider bearing and confirms the recent findings of Nabhani et al 26 for porous squeeze film between circular discs. All these comments are also valid for the case of a deformable slider bearing ( Figure 5).…”

Section: The Load-carrying Capacitysupporting

confidence: 91%

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Coupled couple stress and surface roughness effects on elasto-hydrodynamic contact

et al. 2013

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This paper deals with the combined effects of couple stress and surface roughness to inspect the elasto‐hydrodynamic performance of slider bearing systems. On the basis of the couple stress Stokes theory and homogenisation method, the homogenised generalised Reynolds equation including the slider bearing stationary surface deformation is derived. The total deformation include the deformation of smooth surface, taken into account by the elastic thin layer model, and the deformation of roughness corresponding to a sinusoidal normal displacement on an elastic half space of identical wavelength. The governing equations are discretised by the finite difference method, and the obtained algebraic equations are solved using the iterative overrelaxation Gauss–Seidel technique. The load‐carrying capacity and friction coefficient are presented for transverse, longitudinal and anisotropic roughness patterns for different values of the couple stress parameter in both rigid and deformable cases. The simulation results indicate that the interaction between couple stress, surface roughness and elastic deformation effects is significant. Copyright © 2013 John Wiley & Sons, Ltd.

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Section: The Load-carrying Capacitysupporting

confidence: 91%

“…for larger chain lengths of the additives molecule) increases the values of W . This is in good agreement with the results from Elsharkawy and Alyaqout for porous slider bearing and confirms the recent findings of Nabhani et al . for porous squeeze film between circular discs.…”

Section: Resultsmentioning

confidence: 55%

Coupled couple stress and surface roughness effects on elasto-hydrodynamic contact

et al. 2013

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“…The calculation of h , the instantaneous height of the upper disc, is performed using finite differences according to the bisection method. The dimensionless squeezing velocity d h /d t is calculated followed by all the other variables of interest …”

Section: Resultsmentioning

confidence: 99%

“…a sufficiently small H ), and for an impermeable wall at limit z = − H (i.e. ∂ p */∂ z | z = − H = 0), the integral of Equation is equivalent to (Tichy and Bou‐Saïd ),

{\frac{\partial p^{*}}{\partial z}|}_{z = 0} = - \frac{H}{r} \frac{\partial}{\partial r} ((), r \frac{\partial p^{*}}{\partial r}) .

…”

Section: Modified Darcy Lawmentioning

confidence: 99%

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Axisymmetric squeezing of a Phan‐Thien and Tanner lubricant film under imposed constant load in the presence of a poroelastic medium

Yousfi

Bou‐Saïd

Tichy

2015

Lubrication Science

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In this paper, a modified Reynolds equation in polar coordinates using the Phan-Thien and Tanner rheological model is combined with a modified Darcy law describing a poroelastic confining surface. The Phan-Thien and Tanner model is commonly used to describe the viscoelastic behaviour of synovial fluid, while the poroelastic model can portray articular cartilage. Together, they may provide a simulation basis for lubrication of the tribology of the knee contact under squeezing. The results obtained for the axisymmetric case are analysed and compared for certain non-Newtonian shear phenomena on the basis of works from the literature. NOMENCLATUREpermeability of lower disc (m 2 ) K volume average modulus of elasticity (Pa m À3 ) ℓ displacement vector of pores (m) m upper disc mass (kg) p pressure (Pa) p atm atmospheric pressure (Pa) p* Phan-Thien and Tanner (PTT) film fluid pressure, in porous media (Pa) p N Newtonian pressure (Pa) r radial coordinate (m) R disc radius (m) t time (s) v 0 initial radial velocity component (ms À1 ) u N Newtonian radial velocity component (ms À1 ) U 1 , U 2 radial velocity components of lower/upper disc (ms À1 ) U Ã 1 ; V Ã 1 PTT velocity components, in porous media/fluid film interface (radial, axial) (m s À1 ) V 1 axial (normal) velocity component of lower disc (ms À1 ) v* PTT fluid particles relative velocity vector, in porous medium (m s À1 ) v f PTT fluid particles absolute velocity vector, in porous medium (m s À1 ) W 1 , W 2 azimuthal velocity components of lower/upper disc (ms À1dynamic viscosity of PTT solvent (Pa s) η r effective viscosity in z-plane, r-direction (Pa s) η θ effective viscosity in z-plane, θ-direction (Pa s) θ angular coordinate (À) λ relaxation time (s) ξ PTT slip parameter π zz total axial (normal) stress component (Pa) τ rz extra stress component in z-plane, r-direction (Pa)

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Investigation of couple stress effects on poroelastic squeeze film of parallel plates

Gbehe

Khlifi

Nabhani

et al. 2016

Lubrication Science

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The couple stress effects on hydrodynamic performances of poroelastic squeeze film in the case of infinitely long parallel plates are examined in this paper. The lower plate is a poroelastic matrix saturated by a Newtonian fluid. The poroelasticity is taken into account by the means of homogenisation method. The rheological behaviour of the lubricant is described by the Stokes couple stress fluid theory. The modified Reynolds equation accounting for the couple stress, the elasticity of the poroelastic plate and the slip velocity condition at the film–poroelastic plate interface is derived. The governing equations in the fluid film and poroelastic plate are discretised by finite difference method and solved iteratively by using Gauss–Seidel method. The fluid film and poroelastic plate coupling is managed by the iterative fixed point technique. A computer program is developed in this study. The result analysis shows that couple stress effects on poroelastic squeeze film performances are significant. Copyright © 2016 John Wiley & Sons, Ltd.

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Combined Non-Newtonian and Viscous Shear Effects on Porous Squeeze Film Behavior

Cited by 15 publications

References 18 publications

Coupled couple stress and surface roughness effects on elasto-hydrodynamic contact

Coupled couple stress and surface roughness effects on elasto-hydrodynamic contact

Axisymmetric squeezing of a Phan‐Thien and Tanner lubricant film under imposed constant load in the presence of a poroelastic medium

Investigation of couple stress effects on poroelastic squeeze film of parallel plates

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