scholarly journals The combined effect of couple stresses, variable viscosity and velocity-slip on the lubrication of finite journal bearings

2020 ◽  
Vol 11 (2) ◽  
pp. 501-518
Author(s):  
Tyrone Dass ◽  
Sreedhara Rao Gunakala ◽  
Donna M.G. Comissiong
Keyword(s):  
Variable Viscosity ◽  
Velocity Slip ◽  
Journal Bearings ◽  
Combined Effect ◽  
Couple Stresses

scholarly journals THE COMBINED EFFECT OF MAGNETIC FLUIDS WITH COUPLE STRESSES, VARIABLE VISCOSITY AND VELOCITY-SLIP ON THE LUBRICATION OF FINITE JOURNAL BEARINGS

2020 ◽  
Author(s):  
Tyrone Dass ◽  
Sreedhara Rao Gunakala ◽  
Donna Comissiong
Keyword(s):  
Journal Bearing ◽  
Slip Surface ◽  
Variable Viscosity ◽  
Frictional Coefficient ◽  
Velocity Slip ◽  
Journal Bearings ◽  
Combined Effect ◽  
Viscosity Parameter ◽  
Load Carrying ◽  
Lubrication Characteristics

In this paper, we examine the combined effect of a non-Newtonian couple-stress lubricant, and a magnetic fluid, together with velocity-slip and piezo-viscosity, has on the lubrication characteristics of a finite journal bearing. Using the Stokes micro-continuum theorem and the Barus formula with an artificial (homogeneous) slip surface, we investigate the load-carrying ability, pressure distribution, and frictional coefficient of the bearing. Our results indicate that the piezo-viscosity parameter improves the maximum magnetic and hydrodynamic pressures of the journal bearing. The combined effect also significantly enhances the bearing characteristics.

Peristaltic flow of a Jeffery fluid over a porous conduit in the presence of variable liquid properties and convective boundary conditions

2019 ◽  
Vol 6 (2) ◽  
Author(s):  
G. Manjunatha ◽  
C. Rajashekhar ◽  
K. V. Prasad ◽  
Hanumesh Vaidya ◽  
Saraswati
Keyword(s):  
Boundary Conditions ◽  
Frictional Force ◽  
Variable Viscosity ◽  
Pressure Rise ◽  
Velocity Slip ◽  
Peristaltic Flow ◽  
Physical Parameters ◽  
Convective Boundary Conditions ◽  
Convective Boundary ◽  
Closed Form Solutions

The present article addresses the peristaltic flow of a Jeffery fluid over an inclined axisymmetric porous tube with varying viscosity and thermal conductivity. Velocity slip and convective boundary conditions are considered. Resulting governing equations are solved using long wavelength and small Reynolds number approximations. The closed-form solutions are obtained for velocity, streamline, pressure gradient, temperature, pressure rise, and frictional force. The MATLAB numerical simulations are utilized to compute pressure rise and frictional force. The impacts of various physical parameters in the interims for time-averaged flow rate with pressure rise and is examined. The consequences of sinusoidal, multi-sinusoidal, triangular, trapezoidal, and square waveforms on physiological parameters are analyzed and discussed through graphs. The analysis reveals that the presence of variable viscosity helps in controlling the pumping performance of the fluid.

Peristaltic Flow of a Jeffery Fluid with Heat Transfer in an Inclined Porous Tube under the Influence of Slip and Variable Viscosity

2019 ◽  
Vol 393 ◽  
pp. 16-30 ◽  
Author(s):  
Gudekote Manjunatha ◽  
Hanumesh Vaidya ◽  
Choudhari Rajashekhar ◽  
K.V. Prasad
Keyword(s):  
Heat Transfer ◽  
Frictional Force ◽  
Variable Viscosity ◽  
Pressure Rise ◽  
Velocity Slip ◽  
Slip Parameter ◽  
Porous Tube ◽  
Closed Form Solutions ◽  
Long Wavelength ◽  
Frictional Forces

The present paper investigates the role of heat transfer on peristaltic transport of Jeffery liquid in a porous tube. The effect of variable viscosity and slip impacts are taken into account. The closed-form solutions are obtained with the help of long wavelength and small Reynolds number. The results of physiological parameters on velocity, pressure rise, frictional force, trapped bolus, and temperature are plotted graphically. It is seen that the pressure rise and the frictional forces decline with an expansion in the viscosity parameter. The study further demonstrates that an increase in the value of the slip parameter significantly alters the pressure rise, frictional force, and temperature. Moreover, the volume of trapped bolus increases with an increase in the value of the velocity slip parameter.

On the linear stability analysis of finite-hydrodynamic porous journal bearings under coupled stress lubrication

2007 ◽  
Vol 221 (7) ◽  
pp. 831-840 ◽  
Author(s):  
S. K. Guha ◽  
A. K. Chattopadhyay
Keyword(s):  
Reynolds Equation ◽  
Dynamic Performance ◽  
Slip Flow ◽  
Tangential Velocity ◽  
Continuum Theory ◽  
Transient State ◽  
Velocity Slip ◽  
Journal Bearings ◽  
The Stability ◽  
Coupled Stress

The objective of the present investigation is to study theoretically, using the finite-difference techniques, the dynamic performance characteristics of finite-hydrodynamic porous journal bearings lubricated with coupled stress fluids. In the analysis based on the Stokes micro-continuum theory of the rheological effects of coupled stress fluids, a modified form of Reynolds equation governing the transient-state hydrodynamic film pressures in porous journal bearings with the effect of slip flow of coupled stress fluid as lubricant is obtained. Moreover, the tangential velocity slip at the surface of porous bush has been considered by using Beavers-Joseph criterion. Using the first-order perturbation of the modified Reynolds equation, the stability characteristics in terms of threshold stability parameter and whirl ratios are obtained for various parameters viz. permeability factor, slip coefficient, bearing feeding parameter, and eccentricity ratio. The results show that the coupled stress fluid exhibits better stability in comparison with Newtonian fluid.

Couple-stress squeeze films between porous rectangular plates

2003 ◽  
Vol 217 (3) ◽  
pp. 229-234 ◽  
Author(s):  
N. B. Naduvinamani ◽  
Syeda Tasneem Fathima ◽  
P. S. Hiremath
Keyword(s):  
Couple Stress ◽  
Reynolds Equation ◽  
Velocity Slip ◽  
Squeeze Film ◽  
Rectangular Plates ◽  
Couple Stresses ◽  
Load Carrying ◽  
Porous Interface ◽  
Couple Stress Fluids ◽  
Film Lubrication

In this paper, the squeeze-film lubrication theory between two isotropic porous rectangular plates has been advanced to analyse the effects of couple stresses arising due to the presence of microstructure additives in the lubricant, using the Stokes theory of couple-stress fluids. The most general form of the modified Reynolds equation is derived for the squeeze-film lubrication of the porous rectangular plates by taking into account of the velocity slip at the porous interface. An eigentype of expression is obtained for the squeeze-film pressure. The effects of the isotropic permeability, the couple stresses and the velocity slip parameters on the characteristics of the squeeze-film lubrication are discussed. A significant increase in the load-carrying capacity and the delayed squeeze-film time are observed for the couple-stress fluids in comparison with Newtonian fluids.

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