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Wyświetlanie 1-15 z 24
Tytuł:
The onset of thermal convection in couple-stress fluid in hydromagnetics saturating a porous medium
Autorzy:
Rana, G. C.
Powiązania:
https://bibliotekanauki.pl/articles/201216.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
couple stress fluid
magnetic field
porous medium
thermal convection
Opis:
In this paper, the effect of magnetic field on thermal convection in couple-stress fluid saturating a porous medium is considered. By applying linear stability theory and the normal mode analysis method, a mathematical theorem is derived which states that the viscoelastic thermal convection at marginal state, cannot manifest as stationary convection if the thermal Rayleigh number R, the medium permeability parameter Pι the couple-stress parameter F and the Chandrasekher number Q, satisfy the inequality R ≤4π2/Pl (1 + 2π2F + PlQ/2ε) the result clearly establishes the stabilizing character of couple-stress parameter and magnetic field whereas destabilizing character of medium permeability.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 2; 357-362
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of slip condition on viscoelastic MHD oscillatory forced convection flow in a vertical channel with heat radiation
Autorzy:
Singh, K. D.
Powiązania:
https://bibliotekanauki.pl/articles/955264.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
magnetohydrodynamika
konwekcja wymuszona
lepkosprężystość
porowatość
oscillatory
MHD
forced convection
viscoelastic
slip flow
porous medium
Opis:
In this paper an oscillatory flow of a viscoelastic, incompressible and electrically conducting fluid through a porous medium bounded by two infinite vertical parallel plates is discussed. One of these plates is subjected to a slip-flow condition and the other to a no-slip condition. The pressure gradient in the channel oscillates with time. A magnetic field of uniform strength is applied in the direction perpendicular to the plates. The induced magnetic field is neglected due to the assumption of a small magnetic Reynolds number. The temperature difference of the two plates is also assumed high enough to induce heat transfer due to radiation. A closed form analytical solution to the problem is obtained. The analytical results are evaluated numerically and then presented graphically to discuss in detail the effects of different parameters entering into the problem. A number of particular cases have been shown by dotted curves in the figures. During the analysis it is found that the physical and the mathematical formulations of the problems by Makinde and Mhone (2005), Mehmood and Ali (2007), Kumar et al. (2010) and Choudhury and Das (2012) are not correct. The correct solutions to all these important oscillatory flow problems are deduced.
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 4; 1237-1248
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Combined effects of helical force and rotation on stationary convection of a binary ferrofluid in a porous medium
Autorzy:
Kpossa, M.
Monwanou, A. V.
Powiązania:
https://bibliotekanauki.pl/articles/2174187.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
konwekcja
ferrofluid
ośrodek porowaty
helical force
stationary convection
binary mixture of ferrofluid
porous medium
rotation
Opis:
This work studies the simultaneous effects of helical force, rotation and porosity on the appearance of stationary convection in a binary mixture of a ferrofluid and on the size of convection cells. We have determined the analytical expression of the Rayleigh number of the system as a function of the dimensionless parameters. The effect of each parameter on the system is studied. The consideration of the simultaneous effect of the basic characteristics made it possible to determine the evolution of the convection threshold in the ferrofluid and then the size of convection cells. The analyzes of the various results obtained allowed us to deduce whether the convection sets in quickly or with a delay when the various effects taken into account in the study are considered simultaneously.
Źródło:
International Journal of Applied Mechanics and Engineering; 2022, 27, 2; 158--176
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of magnetic field dependent viscosity on ferromagnetic convection in a rotating sparsely distributed porous medium - revisited
Autorzy:
Prakash, J.
Kumar, P.
Manan, S.
Sharma, K. R.
Powiązania:
https://bibliotekanauki.pl/articles/265547.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
ferrofluid
konwekcja
pole magnetyczne
materiał porowaty
convection
rotation
magnetic field dependent viscosity
porous medium
Opis:
The effect of magnetic field dependent (MFD) viscosity on the thermal convection in a ferrofluid layer saturating a sparsely distributed porous medium has been investigated by using the Darcy-Brinkman model in the simultaneous presence of a uniform vertical magnetic field and a uniform vertical rotation. A correction is applied to the study of Vaidyanathan et al. [11] which is very important in order to predict the correct behavior of MFD viscosity. A linear stability analysis has been carried out for stationary modes and oscillatory modes separately. The critical wave number and critical Rayleigh number for the onset of instability, for the case of free boundaries, are determined numerically for sufficiently large values of the magnetic parameterM1 . Numerical results are obtained and are illustrated graphically. It is shown that magnetic field dependent viscosity has a destabilizing effect on the system for the case of stationary mode and a stabilizing effect for the case of oscillatory mode, whereas magnetization has a destabilizing effect.
Źródło:
International Journal of Applied Mechanics and Engineering; 2020, 25, 1; 142-158
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of suspended particles on thermosolutal convection of Rivlin-Ericksen fluid in porous medium with variable gravity
Autorzy:
Aggarwal, A. K.
Dixit, D.
Powiązania:
https://bibliotekanauki.pl/articles/264370.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
płyn Rivlina-Ericksena
cząstki zawieszone
materiały porowate
zmienna grawitacja
thermosolutal convection
Rivlin-Ericksen fluid
suspended particles
porous medium
varying gravity
Opis:
The thermosolutal stability of a layer of the Rivlin-Ericksen fluid in a porous medium is considered under varying gravity conditions. It is found that for stationary convection, medium permeability and suspended particles have a destabilizing/stabilizing effect when gravity increases/decreases. The stable solute gradient has a stabilizing effect on the system.
Źródło:
International Journal of Applied Mechanics and Engineering; 2018, 23, 3; 813-820
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radiation and chemical reaction effects on unsteady MHD free convection parabolic flow past an infinite isothermal vertical plate with viscous dissipation
Autorzy:
Reddy, B. Prabhakar
Powiązania:
https://bibliotekanauki.pl/articles/265160.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
promieniowanie
reakcja chemiczna
magnetohydrodynamika
swobodna konwekcja
płyta pionowa
radiation parameter
chemical reaction parameter
porous medium
MHD
free convection
isothermal vertical plate
Opis:
The numerical investigation of the effects of radiation and chemical reaction on an unsteady MHD free convection flow with a parabolic starting motion of an infinite isothermal vertical porous plate taking into account the viscous dissipation effect has been carried out. The fluid is considered a gray, absorbing emitting radiation but a non-scattering medium. The dimensionless governing equations for this investigation are solved numerically by applying the Ritz finite element method. Numerical results for the velocity profiles, temperature profiles and concentration profiles as well as the skin-friction are presented through graphs and tables for different values of the physical parameters involved. Results obtained show a decrease in the temperature and velocity in the boundary layer as the radiation parameter increased. The velocity increases with an increase in the thermal and mass Grashof numbers and decreases with an increase in the magnetic parameter. Further, the concentration and velocity decreases with increasing the Schmidt number and chemical reaction parameter. These findings are in very good agreement with the studies reported earlier.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 2; 343-358
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Hall current on unsteady hydromagnetic free convection flow past an impulsively moving vertical plate with Newtonian heating
Autorzy:
Seth, G. S.
Sarkar, S.
Sharma, R.
Powiązania:
https://bibliotekanauki.pl/articles/264598.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
przepływ konwekcyjny
transformacja Laplace'a
tarcie
hydromagnetic free convection flow
Newtonian heating
Hall current
porous medium
INVLAP routine in Matlab
Opis:
An investigation of unsteady hydromagnetic free convection flow of a viscous, incompressible and electrically conducting fluid past an impulsively moving vertical plate with Newtonian surface heating embedded in a porous medium taking into account the effects of Hall current is carried out. The governing partial differential equations are first subjected to the Laplace transformation and then inverted numerically using INVLAP routine of Matlab. The governing partial differential equations are also solved numerically by the Crank-Nicolson implicit finite difference scheme and a comparison has been provided between the two solutions. The numerical solutions for velocity and temperature are plotted graphically whereas the numerical results of skin friction and the Nusselt number are presented in tabular form for various parameters of interest. The present solution in special case is compared with a previously obtained solution and is found to be in excellent agreement.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 1; 187-203
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FEM simulation of triple diffusive natural convection along inclined plate in porous medium: prescribed surface heat, solute and nanoparticles flux
Autorzy:
Goyal, M.
Goyal, R
Bhargava, R.
Powiązania:
https://bibliotekanauki.pl/articles/266289.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
triple diffusive
natural convection
nanofluid
binary base fluid
porous medium
solutal concentration flux
nanoparticle concentration flux
inclined plate
naturalna konwekcja
płyn bazowy
nanocząstki
Opis:
In this paper, triple diffusive natural convection under Darcy flow over an inclined plate embedded in a porous medium saturated with a binary base fluid containing nanoparticles and two salts is studied. The model used for the nanofluid is the one which incorporates the effects of Brownian motion and thermophoresis. In addition, the thermal energy equations include regular diffusion and cross-diffusion terms. The vertical surface has the heat, mass and nanoparticle fluxes each prescribed as a power law function of the distance along the wall. The boundary layer equations are transformed into a set of ordinary differential equations with the help of group theory transformations. A wide range of parameter values are chosen to bring out the effect of buoyancy ratio, regular Lewis number and modified Dufour parameters of both salts and nanofluid parameters with varying angle of inclinations. The effects of parameters on the velocity, temperature, solutal and nanoparticles volume fraction profiles, as well as on the important parameters of heat and mass transfer, i.e., the reduced Nusselt, regular and nanofluid Sherwood numbers, are discussed. Such problems find application in extrusion of metals, polymers and ceramics, production of plastic films, insulation of wires and liquid packaging.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 4; 883--900
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Natural convection in a hydrodynamically and thermally anisotropic non-rectangular porous cavity: effect of internal heat generation/absorption
Autorzy:
Chandran, P.
Sacheti, N. C.
Bhadauria, B. S.
Singh, A. K.
Powiązania:
https://bibliotekanauki.pl/articles/264468.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
konwekcja naturalna
materiały porowate
przepuszczalność
dyfuzyjność cieplna
źródło ciepła
natural convection
trapezoidal cavity
porous medium
permeability
thermal diffusivity
Darcy's law
heat source/sink
Opis:
Laminar natural convection in a trapezoidal porous vertical cavity has been investigated in this work. It is assumed that the porous enclosure is filled up with a permeable material subject to hydrodynamic and thermal anisotropy, the flow being governed by the Darcy law as applicable to a non-isotropic medium. It is further assumed that (i) there is heating at the left vertical wall and cooling at the right wall of the enclosure and (ii) the flow domain is subject to the presence of heat source or heat sink. The partial differential equations governing the resulting free convection have been solved numerically in the non-dimensional forms. There arises a number of parameters relating to buoyancy, internal heating, cavity aspect ratio and inclination of the upper surface to the horizontal. The influence of these parameters has been illustrated and analyzed through contours of streamlines and isotherms. We have also discussed the role of internal heating as well as anisotropy on the heat transfer characteristics.
Źródło:
International Journal of Applied Mechanics and Engineering; 2018, 23, 3; 595-609
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Similarity solution for combined free-forced convection past a vertical porous plate in a porous medium with a convective surface boundary condition
Autorzy:
Garg, P.
Purohit, G. N.
Chaudhary, R. C.
Powiązania:
https://bibliotekanauki.pl/articles/265568.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
płyta porowata
tarcie
ośrodek porowaty
konwekcja
combined convection
fixed vertical porous plate
skin-friction coefficient
Nusselt number
convective surface boundary condition
porous medium
Opis:
This paper studies the mathematical implications of the two dimensional viscous steady laminar combined free-forced convective flow of an incompressible fluid over a semi infinite fixed vertical porous plate embedded in a porous medium. It is assumed that the left surface of the plate is heated by convection from a hot fluid which is at a temperature higher than the temperature of the fluid on the right surface of the vertical plate. To achieve numerical consistency for the problem under consideration, the governing non linear partial differential equations are first transformed into a system of ordinary differential equations using a similarity variable and then solved numerically under conditions admitting similarity solutions. The effects of the physical parameters of both the incompressible fluid and the vertical plate on the dimensionless velocity and temperature profiles are studied and analysed and the results are depicted both graphically and in a tabular form. Finally, algebraic expressions and the numerical values are obtained for the local skin-friction coefficient and the local Nusselt number.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 4; 827-836
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamic analysis of radiating nanofluids mixed convection within concentric pipes filled with a porous medium
Autorzy:
Makinde, Oluwole Daniel
Mabood, Fazle
Khan, Waqar Ahmed
Makinde, Anuoluwa Esther
Powiązania:
https://bibliotekanauki.pl/articles/38910057.pdf
Data publikacji:
2023
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
nanofluid
concentric pipes
mixed convection
thermal radiation
porous medium
entropy analysis
Opis:
In this study, the entropy generation resulting from heat and mass transfer of waterbased nanofluid through an annulus within two concentric vertical pipes filled with a porous medium is investigated. This study considers the effects of thermal radiation, viscous dissipation, thermal buoyancy, and axial pressure gradient in addition to heat and mass transfer. Brownian motion and thermophoresis have been introduced through the Buongiorno model. The similarity solution was used to solve nonlinear ordinary differential equations. The RungeKutta-Fehlberg method is used to solve these equations with the related boundary conditions. The effects of pertinent parameters such as pressure gradient, thermal radiation, viscosity parameter, thermophoretic parameter, Brownian motion parameter, and Eckert number are investigated numerically. This study found that the Bejan number increases as the viscosity parameter increases and decreases as the other active parameters increase. As the radiation parameter, thermophoretic parameter, Brownian parameter, and Eckert number increase, the Nusselt number decreases. The total entropy generation rate is found to increase with the fluid viscosity rate, Grashof number, thermal Biot number, and variable pressure gradient. However, the Bejan number is found to decrease with these parameters, as well as the Prandtl number.
Źródło:
Engineering Transactions; 2023, 71, 3; 419-438
0867-888X
Pojawia się w:
Engineering Transactions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of chemically reactive species and thermal radiation effects on an unsteady MHD free convection flow through a porous medium past a flat plate with ramped wall temperature
Autorzy:
Pandit, K. K.
Sarma, D.
Singh, S. I.
Powiązania:
https://bibliotekanauki.pl/articles/264711.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
free convection
chemical reaction
thermal radiation
MHD
porous medium
ramped temperature
konwekcja swobodna
reakcja chemiczna
promieniowanie cieplne
magnetohydrodynamika
ośrodek porowaty
Opis:
An investigation of the effects of a chemical reaction and thermal radiation on unsteady MHD free convection heat and mass transfer flow of an electrically conducting, viscous, incompressible fluid past a vertical infinite flat plate embedded in a porous medium is carried out. The flow is induced by a general time-dependent movement of the vertical plate, and the cases of ramped temperature and isothermal plates are studied. An exact solution of the governing equations is obtained in closed form by the Laplace Transform technique. Some applications of practical interest for different types of plate motions are discussed. The numerical values of fluid velocity, temperature and species concentration are displayed graphically whereas the numerical values of skin friction, Nusselt number and Sherwood number are presented in a tabular form for various values of pertinent flow parameters for both ramped temperature and isothermal plates.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 4; 945-964
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Natural convection flow in semi-trapezoidal porous enclosure filled with alumina-water nanofluid using Tiwari and Das’ nanofluid model
Autorzy:
Vedavathi, Nallapati
Venkatadri, Kothuru
Fazuruddin, Syed
Raju, G. Sankara Sekhar
Powiązania:
https://bibliotekanauki.pl/articles/38889212.pdf
Data publikacji:
2022
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
natural convection
laminar flow
porous medium
nanofluid
semi-trapezoidal enclosure
Opis:
Nowadays, optimal parameters are necessary for heat transfer enhancement in different practical applications. A numerical simulation of natural convection in a semi-trapezoidal enclosure embedded with porous medium is presented. Stream function and temperature using the Darcy–Boussinesq approximation and Tiwari and Das’ nanofluid model with new more realistic empirical correlations for the physical properties of the nanofluids are formulated. The developed partial differential equations are employed with the help of the stream function approach. The in-house developed computational MATLAB code is validated with the previously published work. The impact of a wide range of governing parameters on fluid flow patterns and temperature gradient variations is presented. The thermal Rayleigh number (Ra) can be a control key parameter for heat and convective flow. Thermal dispersion effects are also examined in this study. An increase in the Rayleigh number leads to an increase in heat transfer, where one can find a reduction of convective heat transfer with φ.
Źródło:
Engineering Transactions; 2022, 70, 4; 303-318
0867-888X
Pojawia się w:
Engineering Transactions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magneto-rotatory compressible couple-stress fluid heated from below in porous medium
Autorzy:
Mehta, C. B.
Powiązania:
https://bibliotekanauki.pl/articles/178540.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
compressible couple-stress fluid
thermal convection
porous medium
rotation
magnetic field
Opis:
The study is aimed at analysing thermal convection in a compressible couple stress fluid in a porous medium in the presence of rotation and magnetic field. After linearizing the relevant equations, the perturbation equations are analysed in terms of normal modes. A dispersion relation governing the effects of rotation, magnetic field, couple stress parameter and medium permeability have been examined. For a stationary convection, the rotation postpones the onset of convection in a couple stress fluid heated from below in a porous medium in the presence of a magnetic field. Whereas, the magnetic field and couple stress postpones and hastens the onset of convection in the presence of rotation and the medium permeability hastens and postpones the onset of convection with conditions on Taylor number. Further the oscillatory modes are introduced due to the presence of rotation and the magnetic field which were non-existent in their absence, and hence the principle of exchange stands valid. The sufficient conditions for nonexistence of over stability are also obtained.
Źródło:
Studia Geotechnica et Mechanica; 2016, 38, 1; 55-63
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of rotation on Jeffrey nanofluid flow saturated by a porous medium
Autorzy:
Rana, Gian C.
Powiązania:
https://bibliotekanauki.pl/articles/1839839.pdf
Data publikacji:
2021
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
nanofluid
Jeffrey model
convection
porous medium
rotation
nanopłyn
model Jeffreya
konwekcja
medium porowate
rotacja
Opis:
In this paper, the effects of rotation on a Jeffery nanofluid flow in a porous medium which is heated from below is studied. Darcy model is employed for porous medium and the Jeffrey fluid model is used as a base fluid. The Navier-Stokes equations of motion of fluid are modified under the influence of the Jeffrey parameter, naoparticles and rotation. The basic perturbation technique based on normal modes is applied to derive the dispersion relation for a Rayleigh number. The effects of the Taylor number, Jeffrey parameter, Lewis number, modified diffusivity ratio, nanoparticles Rayleigh number and medium porosity on the stationary convection of the physical system have been analyzed analytically and graphically. It is observed that the rotation parameter has a stabilising influence for both bottom/top-heavy configurations.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2021, 20, 3; 17-29
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 24

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