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1

Numerical investigation on the effects of obstruction and side ratio on non-Newtonian fluid flow behavior around a rectangular barrier

Noferesti Sara, Ghassemi Hassan, Nowruzi Hashem

Journal of Applied Mathematics and Computational Mechanics

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2019

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Vol. 18, nr 1

53--67

EN

In this paper, the characteristics of the flow and forced heat transfer of power law non-Newtonian fluids that flow around a quadrilateral and rectangular cylinder that are located in a 2D channel are investigated by use of the finite volume method (FVM) in a steady state flow regime. To this accomplishment, in the constant temperature, the effects of a different obstruction ratio, aspect ratio and Reynolds number are investigated. The Reynolds number in the range 5 ≤ Re ≤ 40, the power index in the range 0.5 ≤ n ≤ 1.4, the aspect ratio in the range 0.5 ≤ a ≤ 2, and the obstruction ratio in the range 0.125 ≤ b ≤ 0.5 were selected. By surveying the drag coefficient profiles, it’s concluded that as the obstruction ratio increases, the drag coefficient is increased, while an increase in the Reynolds number causes the lower drag coefficient. In addition, the drag coefficient is strongly increased by aspect ratio enhancements.

2

Non-Newtonian momentum transfer past an isothermal stretching sheet with applied suction

Veena P. H., Suresh B., Pravin V. K., Goud A. M.

International Journal of Applied Mechanics and Engineering

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2017

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Vol. 22, no. 3

665--674

EN

The paper discusses the flow of an incompressible non-Newtonian fluid due to stretching of a plane elastic surface in a saturated porous medium in the approximation of boundary layer theory. An exact analytical solution of non-linear MHD momentum equation governing the self-similar flow is given. The skin friction co-efficient decreases with an increase in the visco-elastic parameter k1 and increase in the values of both the magnetic parameter and permeability parameter.

3

Curvilinear squeeze film bearing with porous wall lubricated by a Rabinowitsch fluid

Walicka A., Walicki E., Jurczak P., Falicki J.

International Journal of Applied Mechanics and Engineering

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2017

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Vol. 22, no. 2

427--441

EN

The present theoretical analysis is to investigate the effect of non-Newtonian lubricant modelled by a Rabinowitsch fluid on the performance of a curvilinear squeeze film bearing with one porous wall. The equations of motion of a Rabinowitsch fluid are used to derive the Reynolds equation. After general considerations on the flow in a bearing clearance and in a porous layer using the Morgan-Cameron approximation the modified Reynolds equation is obtained. The analytical solution of this equation for the case of a squeeze film bearing is presented. As a result one obtains the formulae expressing pressure distribution and load-carrying capacity. Thrust radial bearing and spherical bearing with a squeeze film are considered as numerical examples.

4

Mathematical modeling of fluid flow in the doubly connected area

Kopylov S., Szafran K.

Prace Instytutu Lotnictwa

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2016

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Nr 4 (245)

218--226

EN

The article presents the study of the flow of non-Newtonian liquid on the hydrodynamic initial section in doubly connected region. A method which allows solving this problem is to use the principle of conservation of momentum for a moving fluid. The study used the equation Navier- Stokesa for in viscid fluid moving in a two dimensional space. For the solution of the Navier-Stokes equations it is necessary to know the function of cross linking for the velocity distribution in hydrodynamic initial section in doubly connected region. This function was obtained by integrating the Navier-Stokes equations and after substitution in the equation for the distribution of local velocities allows calculating the local velocity in the liquid flow on the hydrodynamic initial section in doubly connected region. In addition to the analysis of the function of cross linking was discussed.

PL

W artykule przedstawiono analizę przepływu cieczy nienewtonowskiej na styku początkowym podwójnie połączonego odcinka hydraulicznego. Sposób, który pozwala na rozwiązanie tego problemu to jest zastosowanie zasady zachowania pędu do poruszającego się płynu. W badaniu analitycznym zastosowano równanie Naviera-Stokesa dla lepkiego płynu poruszającego się w przestrzeni dwuwymiarowej. Do układu równań Naviera-Stokesa należy wprowadzić funkcję sieciowania dla rozkładu prędkości na początku przepływu hydrodynamicznego w dwuwymiarowym obszarze. Funkcję otrzymano przez całkowanie równań Naviera-Stokesa. Po podstawieniu do równań dla rozkładu lokalnych prędkości umożliwiło to obliczenie lokalnej prędkości w cieczy w dwuwymiarowym przepływie hydrodynamicznym.

5

Global stability for thermal convection in a couple-stress fluid with temperature and pressure dependent viscosity

Choudhary S. S., Bharti P. K.

Studia Geotechnica et Mechanica

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2013

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Vol. 35, nr 3

85--102

EN

We show that the global nonlinear stability threshold for convection in a couple-stress fluid with temperature and pressure dependent viscosity is exactly the same as the linear instability boundary. This optimal result is important because it shows that linearized instability theory has captured completely the physics of the onset of convection. It has also been found that the couplestress fluid is more stable than the ordinary viscous fluid and then the effect of couple-stress parameter (F) and variable dependent viscosity (Γ) on the onset of convection is also analyzed.

6

Dyspergowanie cieczy w płynie nieniutonowskim poprzez jej wypływ z dystrybutora

Hapanowicz J.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2008

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Vol. 324, z. 90

59-77

PL

W artykule przedstawiono wyniki badań dotyczących wielkości i prędkości ruchu kropel oleju w wodnych roztworach polimeru. Krople wytwarzano na drodze wypływu różnych strumieni oleju z pojedynczych otworów dystrybucyjnych o trzech średnicach. Roztwory polimerów wykazywały cechy płynów nieniutonowskich rozrzedzanych ścinaniem. Na podstawie analizy wyników badań, opracowano równania opisujące wielkość i prędkość ruchu kropel w obszarze ich wypływu z dystrybutora.

EN

In the paper results of investigation concerning of size and velocity oil drops in aqueous solutions of polymer have been presented. Drops were generated as result of outflow different oil streams from singles distributors of three diameters. Solutions of polymer were pseudoplastic fluids. Basing of test results, the equations for size and velocity of drops in area of outflow from distributor worked out.

7

Unsteady MHD Flow in a Circular Pipe of a Dusty Non-Newtonian Fluid

Attia H. A., Ahmed M. E. S.

Mechanics and Mechanical Engineering

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2007

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Vol. 11, nr 1

113-127

EN

In this paper, the unsteady magnetohydrodynamic flow of a dusty viscous incompressible electrically conducting non-Newtonian Casson fluid through a circular pipe is investigated. A constant pressure gradient in the axial direction and a uniform magnetic field directed perpendicular to the flow direction are applied. The particle-phase is assumed to behave as a viscous fluid. A numerical solution is obtained for the governing nonlinear momentum equations using finite differences. The effect of the magnetic field, the non-Newtonian fluid characteristics, and the particle-phase viscosity on the transient behavior of the velocity, volumetric flow rates, and skin friction coeffcients of both fluid and particle-phases are studied. It is found that all the flow parameters for both phases decrease as the magnetic field increases or the flow index decreases. On the other hand, increasing the particle-phase viscosity increases the skin friction of the particle phase, but decreases the other flow parameters.

8

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.

9

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.