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1
Content available Simple flows of pseudoplastic fluids based on DeHaven model
Walicka A.
International Journal of Applied Mechanics and Engineering
|
2017
|
Vol. 22, no. 4
1035--1044
EN
In this paper three simple flows of visco-plastic fluids of DeHaven type or fluids similar to them are considered. These flows are: Poiseuille flow in a plane channel, Poiseuille flow through a circular pipe and rotating Couette flow between two coaxial cylinders. After presentation DeHaven model it was presented some models of fluids similar to this model. Next it was given the solutions of equations of motion for three flows mentioned above.
2
Content available Porous squeeze film bearing with rough surfaces lubricated by a Bingham fluid
Walicka A., Walicki E., Jurczak P., Falicki J.
International Journal of Applied Mechanics and Engineering
|
2014
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Vol. 19, no. 4
795--808
EN
In the paper the effect of both bearing surfaces and the porosity of one bearing surface on the pressure distribution and load-carrying capacity of a squeeze film bearing is discussed. The equations of motion of a Bingham fluid in a bearing clearance and in a porous layer are presented. Using the Morgan-Cameron approximation and Christensen theory of rough lubrication the modified Reynolds equation is obtained. The analytical solutions of this equation for a squeeze film bearing are presented. As a result one obtains the formulae expressing pressure distribution and load-carrying capacity. A thrust radial bearing is considered as a numerical example.
3
Content available On thermosolutal convection in presence of compressible fluid with fine dust
Singh M., Gupta R. K.
International Journal of Applied Mechanics and Engineering
|
2014
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Vol. 19, no. 1
133--143
EN
A layer of a Rivlin-Ericksen elastico-viscous fluid heated and soluted from below in the presence of compressibility and suspended particles (fine dust) effect is considered. For stationary convection, the Rivlin- Ericksen, elastico-viscous fluid behaves like a Newtonian fluid. The oscillatory modes are introduced due to the presence of a stable solute gradient, suspended particles destabilize the system whereas the stable solute gradient has a stabilizing effect on the system and the effect of compressibility is to postpone the onset of thermosolutal convection. The stable solute gradient and compressibility postpone the onset of convection, whereas the suspended particles hasten the onset of convection. The stable solute gradient introduces oscillatory modes in the systems which were non-existent in its absence.
4
Content available Thermosolutal instability in compressible viscoelastic dusty fluid through porous medium
Kumar P., Mohan H.
International Journal of Applied Mechanics and Engineering
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2013
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Vol. 18, no. 1
99--112
EN
Thermosolutal instability in a compressible Walters B’ viscoelastic fluid with suspended particles through a porous medium is considered. Following the linearized stability theory and normal mode analysis, the dispersion relation is obtained. For stationary convection, the Walters B’ viscoelastic fluid behaves like a Newtonian fluid and it is found that suspended particles and medium permeability have a destabilizing effect whereas the stable solute gradient and compressibility have a stabilizing effect on the system. Graphs have been plotted by giving numerical values to the parameters to depict the stability characteristics. The stable solute gradient and viscoelasticity are found to introduce oscillatory modes in the system which are non-existent in their absence.
5
Content available Heat transfer of viscoelastic fluid flow due to nonlinear stretching sheet with internal heat source
Nandeppanavar M. M., Siddalingappa M. N., Jyoti H.
International Journal of Applied Mechanics and Engineering
|
2013
|
Vol. 18, no. 3
739--760
EN
In the present paper, a viscoelastic boundary layer flow and heat transfer over an exponentially stretching continuous sheet in the presence of a heat source/sink has been examined. Loss of energy due to viscous dissipation of the non-Newtonian fluid has been taken into account in this study. Approximate analytical local similar solutions of the highly non-linear momentum equation are obtained for velocity distribution by transforming the equation into Riccati-type and then solving this sequentially. Accuracy of the zero-order analytical solutions for the stream function and velocity are verified by numerical solutions obtained by employing the Runge-Kutta fourth order method involving shooting. Similarity solutions of the temperature equation for non-isothermal boundary conditions are obtained in the form of confluent hypergeometric functions. The effect of various physical parameters on the local skin-friction coefficient and heat transfer characteristics are discussed in detail. It is seen that the rate of heat transfer from the stretching sheet to the fluid can be controlled by suitably choosing the values of the Prandtl number Pr and local Eckert number E, local viscioelastic parameter k1 and local heat source/ sink parameter β.
6
Content available Hall effect on thermal instability of viscoelastic dusty fluid in porous medium
Singh M., Gupta R. K.
International Journal of Applied Mechanics and Engineering
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2013
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Vol. 18, no. 3
871--886
EN
The effect of Hall currents and suspended dusty particles on the hydromagnetic stability of a compressible, electrically conducting Rivlin-Ericksen elastico viscous fluid in a porous medium is considered. Following the linearized stability theory and normal mode analysis the dispersion relation is obtained. For the case of stationary convection, Hall currents and suspended particles are found to have destabilizing effects whereas compressibility and magnetic field have stabilizing effects on the system. The medium permeability, however, has stabilizing and destabilizing effects on thermal instability in contrast to its destabilizing effect in the absence of the magnetic field. The critical Rayleigh numbers and the wave numbers of the associated disturbances for the onset of instability as stationary convection are obtained and the behavior of various parameters on critical thermal Rayleigh numbers are depicted graphically. The magnetic field, Hall currents and viscoelasticity parameter are found to introduce oscillatory modes in the systems, which did not exist in the absence of these parameters.
7
Przepływ Poiseuille'a w płaskim kanale płynu Ellisa
Ratajczak M., Walicka A., Walicki E., Ratajczak P.
Inżynieria i Aparatura Chemiczna
|
2006
|
Nr 6s
202-203
EN
Flow of pseudo-plastic fluid through a circular channel is considered in the paper. The problem was solved using the Rotem-Shinnar model. The solution was obtained using an analytic method. As a result, a formula defining the velocity distribution in a channel was received.
8
Osiowo-symetryczny przepływ Poiseuille'a płynu Rotema-Shinnara
Ratajczak M., Walicka A., Walicki E., Ratajczak P.
Inżynieria i Aparatura Chemiczna
|
2006
|
Nr 6s
204-205
EN
Issues of the flat flow of pseudo-plastic fluid in a channel between parallel plates are presented in the paper. The problem was solved using the Ellis model. Based on the analytical solutions of movement equations, and with regard to the Ellis model equation, the velocity distribution in a flat channel was described.
9
Kawitacja w płynach lepkich i lepkosprężystych
Sitka A., Redzicki R.
Inżynieria Chemiczna i Procesowa
|
2006
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T. 27, z. 3/1
847-857
PL
Przedstawiono równania i numeryczne rozwiązania oscylacji pęcherzyka kawitacyjnego w płynie nieniutonowskim lepkim i lepkosprężystym. Właściwości lepkie płynu opisano modelem potęgowym, a właściwoości lepkosprężyste modelem OWF (Oldroyda-Waltersa-Fridricksona). Uzyskane z obliczeń numerycznych charakterystyki oscylacji pojedynczego pęcherzyka kawitacyjnego różnią się dla cieczy niutonowskiej i nieniutonowskiej. Z przeprowadzonej analizy numerycznej wynika, że lepkość i sprężystość płynu w znaczny sposób ograniczają zjawisko kawitacji. Wskazują na to uzyskane charakterystyki zależności oscylacji prędkości i ciśnienia, wykazujące zmniejszenie amplitudy drgań pęcherzyka wraz ze wzrostem lepkości i sprężystości płynu.
EN
The paper presents the equations and numerical solutions of oscillation of the bubble cavitation in the non-Newtonian viscous fluid and viscoelastic fluid. The properties of viscous liquid were described by the involution model and the viscoelastic properties by the OWF (Oldroyd-Walters-Fridrickson) model. The characteristics of oscillation of a single bubble cavitation obtained from the numerical calculations are different for the Newtonian and non-Newtonian liquids. From the numerical analysis it follows that the viscosity and elasticity of fluid significantly limit the cavitation effect. The characteristics of velocity and pressure oscillation show the reduction of vibration amplitude of a bubble along with the increasing viscosity and elasticity of fluid.
10
Content available remote Boundary layer MHD flow of a viscoelastic fluid over a porous quadratic stretching sheet
Khan S. K.
International Journal of Applied Mechanics and Engineering
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2005
|
Vol. 10, no 2
267-279
EN
A mathematical analysis on the boundary layer MHD flow of a viscoelastic fluid over a porous stretching sheet has been presented in this paper. A typical choice of quadratic stretching of the boundary, which generates a quadratic part in velocity parallel to the boundary sheet and a linear mass flux part in the velocity normal to the stretching sheet, has been assumed. Streamline patterns and skin friction coefficients are discussed for various values of nondimensional physical parameters. The result of the analysis reveals that the combined effect of the non-dimensional viscoelastic parameter and Hartmann number is to increase significantly the values of skin friction coefficient, whereas, the combined effect of the nondimensional constant mass flux parameter and modified linear mass flux parameter is to reduce largely the values of skin friction coefficient. For positive values of the linear mass flux parameter the stream functions attain a positive slope away from the origin while they attain a negative slope everywhere for zero value. The limiting cases of our results yield the results of Andersson (1992) and Kumaran and Ramanaiah (1996).
11
Content available remote Oscillatory non-Newtonian viscoelastic fluid flow past a porous bed
Eldabe N. T. M., Sallam S. N., Ghaly A. Y.
Mechanics and Mechanical Engineering
|
2004
|
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.
12
Content available remote On the possibility of overstable motion of a rotating viscoelastic fluid layer heated from below under the effect of magnetic field with one relaxation time
Othman M. I. A.
Mechanics and Mechanical Engineering
|
2004
|
Vol. 7, nr 1
41-51
EN
The convective stability of a horizontal layer of viscoelastic conducting liquid (Walters' liquid B') heated from below and rotating about a vertical axis in the presence of a magnetic field and thermal relaxation has been investigated. Linear stability theory and normal mode analysis are used to derive an eigenvalue system of eighth order, and an exact eigenvalue equation for a neutral instability is obtained. Critical Rayleigh numbers and wave numbers for the onset of instability are presented graphically as functions of Taylor number for various values of the Chandrasekhar number and the relaxation time at a Prandtl number Pr = l.
13
Content available remote Tribology of stochastic phenomena on the hard tissue
Wierzcholski K. C.
International Journal of Applied Mechanics and Engineering
|
2004
|
Vol. 9, no spec.
283-289
EN
The aim of this paper is to show analytical solutions of friction forces and the velocity component of viscoelastic nutrient fluid in the thin layer resting on the surface sample of tissue. Friction forces and stresses are caused by the perfusion in bioreactor. Stochastic Christensen model of rough surfaces of tissue sample is taking into account.
14
Content available remote The integrals of velocity near the tissue in bioreactor
Wierzcholski K. C.
International Journal of Applied Mechanics and Engineering
|
2004
|
Vol. 9, no spec.
291-298
EN
The aim of this paper is to show analytical method of integration of equations of unsteady motion for viscoelastic nutrient fluid in the thin layer resting on the tissue surface. Flow is caused by the perfusion in bioreactor. Stochastic Christensen model of rough surfaces of tissue sample is taking into account. From performed cultivation process of tissue in bioreactor we take into account the advantages in cartilage remodeling and repair in osteoporosis joints.
15
Content available remote Viscoelastic boundary layer MHD flow through a porous medium over a porous quadratic stretching sheet
Kumar Khan S., Sanjayanand E.
Archives of Mechanics
|
2004
|
Vol. 56, nr 3
191-204
EN
Boundary layer MHD flow of a viscoelastic fluid in a porous medium over a porous stretching sheet has been presented in this article. A typical choice of quadratic stretching of the boundary, having a quadratic part in velocity parallel to the boundary sheet and a linear mass flux in the velocity normal to the stretching sheet, constitutes the boundary conditions of the problem. The effect of various values of nondimensional physical parameters on streamline patterns and skin friction coefficient are discussed. Some of the important findings of the article are: (a) the flow is enhanced by the positive values of linear mass flux parameter and suppressed by the negative values of linear mass flux parameter; (b) the effect of permeability parameter is not significant when linear mass flux parameter takes zero or negative values; (c) the combined effect of reduction of the values of permeability parameter, Hartmann number and linear mass flux parameter is expected to reduce largely the values of skin friction coefficient.
16
Content available remote The flow of viscoelastic fluids in an opposed jets rheometer and a Fano flow rheometer
Wilkes C., Gampert B.
International Journal of Applied Mechanics and Engineering
|
2003
|
Vol. 8, no spec.
319-324
EN
The elongational rheometer used for this work is an opposed jet rheometer, which allows elongational flow measurements of highly dilute polymer solutions. The polymer concentrations can be lower than the critical concentration under steady state conditions and lower than the critical concentration in the case of flow conditions. A further experimental set up was used for characterising the viscoelastic fluids. The working method of this apparatus is the tubeless siphon or Fano flow, which can be understood approximately as the reverse fibre spinning process. The beginning of the fibre spinning process can be applied in order to determine the critical concentration . The experimental investigations undertaken here were carried out using a commercial, anionic polyacrylamide with a relatively high molar mass and hydrolysis factor. The polyacrylamide was dissolved in highly pure water. Sodium chloride with different concentrations was added to the solutions to control the partial neutralisation of negative charges at the ends of the polymer chains.
17
Content available remote On the viscoelastic core of a line vortex embedded in a stagnation point flow
Erdogan M. E.
International Journal of Applied Mechanics and Engineering
|
2003
|
Vol. 8, no 4
577-588
EN
The viscoelastic core of a line vortex embedded in a radially inward axisymmetric stagnation point flow for a Maxwell fluid and an Oldroyd B fluid is considered. Velocity, vorticity and stress distributions are calculated and compared with those of the Newtonian fluid. It is found that there are pronounced effects of viscoelastic properties on these distributions with respect to those of the Newtonian fluid.
18
Przepływ uogólnionego płynu drugiego rzędu w przewodzie o przekroju kołowym
Walicki E., Walicka A., Ratajczak P.
Zeszyty Naukowe. Elektryka / Politechnika Opolska
|
1998
|
z. 46
371-375
19
Płaski przepływ uogólnionego płynu lepkosprężystego
Walicka A., Walicki E., Ratajczak P.
Zeszyty Naukowe. Elektryka / Politechnika Opolska
|
1998
|
z. 46
349-354
20
Opory przepływu uogólnionego płynu lepkosprężystego w dyszy klinowej
Walicki E., Walicka A., Ratajczak P.
Zeszyty Naukowe. Elektryka / Politechnika Opolska
|
1998
|
z. 46
355-362
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