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1

Lubrication of asymmetric rollers considering viscosity as function of mean temperature

Lanka Swetha, Sajja Venkata Subrahmanyam, Prasad Dhaneshwar

International Journal of Applied Mechanics and Engineering

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2023

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Vol. 28, no. 2

49--63

EN

A theoretical analysis of an asymmetric roller bearing system with cavitation that is hydro-dynamically lightly loaded and lubricated by a thin, incompressible fluid is presented. The lubricant adheres to the non-Newtonian Bingham plastic fluid concept, in which the viscosity of the fluid should change depending on the mean film temperature. The continuity and momentum equations, which regulate fluid flow, are first solved analytically and then numerically using MATLAB. Through graphs and tables, some key bearing features are addressed and further explained. This leads to the conclusion that there is a discernible difference between Newtonian and non-Newtonian fluids in terms of pressure, temperature, load, and traction. The findings are good in line with the body of literature.

2

Averaging of a nonlinear bipolar model with phase transition and oscillating external forces

Medjo T. T.

Journal of Applied Analysis

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2015

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Vol. 21, nr 2

123--146

EN

In this article, we consider a non-autonomous nonlinear bipolar with phase transition in a two-dimensional bounded domain. We assume that the external force is singularly oscillating and depends on a small parameter ε. We prove the existence of the uniform global attractor Aε. Furthermore, using the method of [9] in the case of the two-dimensional Navier-Stokes systems, we study the convergence of Aε as e goes to zero.

3

Numerical investigations of pulsatile flow in stenosed artery

Bit A., Chattopadhyay H.

Acta of Bioengineering and Biomechanics

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2014

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Vol. 16, no. 4

33--44

EN

Purpose: Abnormalities in blood vessels by virtue of complex blood flow dynamics is being supported by non-Newtonian behavior of blood. Thus it becomes a focus of research to most of the researchers. Additionally, consideration of real life patient specific model of vessel as well as patient specific inlet flow boundary condition implementation was limited in literature. Thus a thorough implementation of these considerations was done here.Method: In this work, a numerical investigation of hemodynamic flow in stenosed artery has been carried out with realistic pulsating profile at the inlet. Flow has been considered to be laminar due to arresting condition of cardiovascular state of the subject. Two non-Newtonian rheological models namely, Power Law viscosity model and Quemada viscosity model have been used. Two different patient-specific pulsatile profiles are considered at the inlet of a long stenosed artery with varying degree of stenoses from 25% to 80%. Results: Transient form of Navier-Stokes equation is solved in an axi-symmetric domain to calculate the detailed flow structure of the flow field. From the simulation data, temporal and time averaged wall shear stress, oscillatory shear index and pressure drop are calculated. Conclusions: The results demonstrate that oscillatory shear index and wall shear stresses areextensively governed by the degree of stenoses. The position and movement of recirculation bubbles are found to vary with flow Reynolds number.

4

Effect of variable viscosity on free flow of non-Newtonian power-law fluids along a vertical surface with thermal stratification

Moorthy M., Senthilvadivu K.

Archives of Thermodynamics

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2012

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Vol. 33, no. 4

109-121

EN

The aim of this paper is to investigate the effect of thermal stratification together with variable viscosity on free convection flow of non-Newtonian fluids along a nonisothermal semi infinite vertical plate embedded in a saturated porous medium. The governing equations of continuity, momentum and energy are transformed into nonlinear ordinary differential equations using similarity transformations and then solved by using the Runge-Kutta-Gill method along with shooting technique. Governing parameters for the problem under study are the variable viscosity, thermal stratification parameter, non-Newtonian parameter and the power-law index parameter.The velocity and temperature distributions are presented and discussed. The Nusselt number is also derived and discussed numerically.

5

Patel M., Timol M. G.

International Journal of Applied Mechanics and Engineering

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2010

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Vol. 15, no 4

1205-1214

EN

A steady three dimensional MHD free convection and mass transfer flow past a semi-infinite surface in the presence of heat generation has been studied numerically for non-Newtonian power law fluids. The governing partial differential equations are reduced to a system of an ordinary differential equation using similarity transformation.

6

MHD heat transfer to non-Newtonian power-law fluids flowing over a wedge with viscous dissipation

Kishan N., Amrutha P.

International Journal of Applied Mechanics and Engineering

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2009

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Vol. 14, no 4

965-987

EN

Fluid flow and heat transfer of a power law fluid flowing over a wedge, taking into consideration viscous dissipation, in the presence of a magnetic field is investigated. The governing partial differential equations are reduced to ordinary differential equations by the application of group theory. By using quasi-linearization technique, first we linearized the coupled non-linear equations are first linearized, and then solved them numerically by a finite difference method. Numerical solutions for the governing momentum and energy equations are obtained. Results are presented as velocity profiles and temperature profiles for different flow parameters, such as, the magnetic field parameter M, Prandtl number Pr, Eckert number Ec, the flow behavior index n, and the wedge angle parameter m. Variations of heat transfer and skin friction for different values of Ec, Pr, M and m are presented. Heat transfer and skin friction results are compared for various values of the flow behaviour index n governing the nature of the fluid and also for different wedge angles.

7

Non-Darcy non-Newtonian free convection flow over a vertical plate under the influence of Soret and Dufour effect

Mahdy A.

International Journal of Applied Mechanics and Engineering

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2008

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Vol. 13, no 4

1125-1132

EN

A non-similar boundary layer analysis is carried out to study the effect of Soret and Dufour on heat and mass transfer for a power-law, non-Newtonian fluid. Thermo-diffusion implies that the heat transfer is induced by concentration gradient, and thermo-diffusion implies that the mass diffusion is induced by thermal gradient. The resultant governing boundary-layer equations, highly non-linear and a coupled form of partial differential equations have been solved by employing a numerical, Runge-Kutta fourth order technique with a modified version of the Newton-Raphson shooting method. A parametric study of all parameters involved is conducted, and a representative of the results for the velocity, temperature, concentration profiles as well as the Nusselt and the Sherwood numbers are illustrated graphically to elucidate interesting features of the solutions.

8

Investigation of a laminar flow of a non-Netonian fluid in a helical pipe

Cheng L., Kuznetsov A. V.

International Journal of Applied Mechanics and Engineering

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2005

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Vol. 10, no 1

21-37

EN

This paper presents a numerical study of a fully developed laminar flow of a non-Newtonian fluid in a helical pipe. An orthogonal helical coordinate system is utilized and the Navier-Stokes equations for the non-Newtonian fluid in this coordinate system are derived. The SIMPLE algorithm with a staggered grid is adopted to solve the governing equations. The effects of the pressure gradient, the curvature, and the torsion on the fully developed laminar flow in helical pipes are investigated. The comparison of flow dynamics between Newtonian and non-Newtonian fluids is presented.

9

Oscillatory non-Newtonian viscoelastic fluid flow past a porous bed

Eldabe N. T. M., Sallam S. N., Ghaly A. Y.

Mechanics and Mechanical Engineering

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2004

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Vol. 7, nr 2

131-144

EN

An analytical study has been performed to evaluate the flow of viscoelastic fluid through and past an infinite porous bed. A most general form of Darcy law has been taken into account when the free stream oscillates with or without a non-zero mean. In modeling the flow in the bed a separation of variable technique was utilized to represent the governing equations with appropriate boundary layer assumption. The effect of flow inertia was taken into consideration. Results obtained include velocity distributions of the fluid in the bed. The dependence of velocity profile on elasticity parameter of the fluid and permeability parameter of the medium with the variation of the time and position was also obtained and discussed graphically.

10

Effects of couple stresses on a pulsatile magnetohydrodynamic viscoelastic flow through a channel bounded by two permeable parallel plates

Eldabe N. T. M., Hassan A. A., Mohamed M. A. A.

Mechanics and Mechanical Engineering

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2004

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Vol. 7, nr 1

5-14

EN

This paper is an analysis of an incompressible unsteady pulsatile laminar flow of electrically conducting non-Newtonian fluid through a channel bounded by two permeable plates taking into account the induced magnetic field and the effect of couple stresses on the flow. Solutions of the equations of motion are obtained by using Mathematica program and the effects of the various parameters entering the problem are discussed with the help of graphs. The main results show that the effect of couple stresses is to decrease the flow velocity and it is to increase (or decrease) the induced magnetic field near one of the boundaries and decrease (or increase) it near the other according to the time variation.

11

Linear and non-linear analyses of convection in a Rivlin-Ericksen fluid-saturated porous medium

Siddheshwar P. G., Sri Krishna C. V.

International Journal of Applied Mechanics and Engineering

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2003

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Vol. 8, no 4

677-692

EN

Linear and non-linear analyses of convection in a second-order Boussinesquian fluid-saturated porous medium are made. The Rivlin-Ericksen constitutive equation is considered to effect a viscoelastic correction to the Brinkman momentum equation together with a single-phase heat transport equation. The linear and non-linear analyses are respectively based on the normal mode technique and the truncated representation of Fourier series. The linear theory reveals that the critical eigenvalue is independent of viscoelastic effects and the principle of exchange of stabilities holds. The non-linear study of cellular convection leads to an autonomous system of differential equations which is solved numerically. The finite amplitude disturbances are found to be independent of transient conditions and viscoelasticity is shown to stabilize the system. The Nusselt number is calculated for different values of the parameters arising in the problem. The possibility of chaotic motion and its similarity to the problem of magnetoconvection are discussed.

12

Complete isothermal solution for the viscous regime of concentrated contact traction

Bair S.

International Journal of Applied Mechanics and Engineering

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2002

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Vol. 7, no 3

719-727

EN

There is sufficient understanding of the rheology of traction in the viscous regime to make accurate calculations from measurable properties. It is no longer necessary to invoke fictitious viscosity or shear-thinning laws.