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1
Content available Soret and dufour effects on mhd flow of a micropolar fluid past over a vertical Riga plate
Borah Keshab, Konch Jadav, Chakraborty Shyamanta
Journal of Applied Mathematics and Computational Mechanics
|
2023
|
Vol. 22, nr 3
5-18
EN
The present study investigates heat and mass transport phenomena associated with the MHD flow of micropolar fluid over a vertically stretched Riga plate under the action of a uniform magnetic field applied parallel to the plate. The objective of the study is to analyze Soret and Dufour effects on this physical situation in the presence of chemical reaction. The governing partial differential equations are converted into ordinary differential equations using suitable similarity transformations. The equations are solved numerically by developing programming codes in MATLAB for the very efficient shooting method along with the fourth order Runge-Kutta scheme. The velocity, microrotation, temperature and species concentration distribution are presented graphically for various emerging physical parameters like Hartmann number, material parameter, Soret number, Dufour number and other dimensionless parameters. It is found that the species concentration distribution profiles increase with increasing Soret number, whereas the temperature distribution profile decreases with an increasing Soret number. This work also provides solutions for shear stress at plates, the rate of heat and mass transfer in addition to those for velocity, microrotation, temperature and species concentration. Comparisons with previous studies are carefully examined, and it is found that they are generally in agreement.
2
Content available Similarity solution of stagnation-point flow and heat transfer of a micropolar fluid towards a horizontal permeable exponentially elongating sheet with radiation, heat production / immersion
Parthiban R., Palani G.
International Journal of Applied Mechanics and Engineering
|
2021
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Vol. 26, no. 4
179--191
EN
The current study aims to explore stagnation spot flow of a micropolar fluid about a plain linear exponentially expanding penetrable surface in the incidence of radiation and in-house heat production/immersion. Through similarity mapping, the mathematical modeling statements are transformed to ODE's and numerical results are found by shooting techniques. The impact of varying physical constants on momentum, micro-rotation and temperature is demonstrated through graphs. The computed measures including shear, couple stress, mass transfer and the local surface heat flux with distinct measures of factors involved in this proposed problem are presented through a table.
3
Content available Micropolar flow over a black isothermal plate in the presence thermal radiation
Raptis A.
International Journal of Applied Mechanics and Engineering
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2021
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Vol. 26, no. 2
235--241
EN
This study numerically investigates the effects of thermal radiation on the flow over a black isothermal plate for an optically thin gray micropolar fluid. The flowing medium absorbs and emits radiation, but scattering is not included. The computational results are discussed graphically for several selected flow parameters.
4
Content available A numerical approach to slip flow of a micropolar fluid above a flat permeable contracting surface
Parthiban R., Palani G., Tinker Seema, Sharma R. P.
International Journal of Applied Mechanics and Engineering
|
2021
|
Vol. 26, no. 2
173--185
EN
A plain linear penetrable contracting sheet with slip over a micro-polar liquid with a stagnation-point flow is analyzed. Through similarity mapping, the mathematical modeling statements are transformed as ODE’s and numerical results are found by shooting techniques. The varying impacts of physical quantities on the momentum, micro-rotation, and temperature were demonstrated through graphs. The computed measures including shear and couple stress with distinct measures of factors involved in this proposed problem are presented through a table.
5
Content available Drag force of a porous particle moving axisymmetrically in a closed cavity of micropolar fluid
Madasu Krishna Prasad
Journal of Applied Mathematics and Computational Mechanics
|
2019
|
Vol. 18, nr 4
41--51
EN
The present paper deals with the problem of an incompressible axisymmetric creeping flow caused by a porous spherical particle in a spherical cavity filled with micropolar fluid. Depending on the kind of cell model, appropriate boundary conditions are used on the surface of sphere and spherical cavity. Drag force on the porous particle in the presence of a cavity is calculated to determine the correction factor to the Stokes law. A general expression for the hydrodynamic force acting on the porous sphere and, hence, for the wall correction factor of the sphere are obtained. The special cases of the porous sphere in viscous fluid, zero permeability solid sphere in micropolar fluid and viscous fluid are obtained in open and closed cavity respectively.
6
Content available Scrutinization of Joule heating and viscous dissipation on MHD flow and melting heat transfer over a stretching sheet
Kumar K. G., Gireesha B. J., Manjunatha S.
International Journal of Applied Mechanics and Engineering
|
2018
|
Vol. 23, no. 2
429--443
EN
The present paper deals with an analysis of the combined effect of Joule heating and viscous dissipation on an MHD boundary layer flow and melting heat transfer of a micro polar fluid over a stretching surface. Governing equations of the problem are transformed into a set of coupled nonlinear ordinary differential equations by applying proper transformations and then they are solved numerically using the RKF-45 method. The method is verified by a comparison with the established results with limiting solution. The influence of the various interesting parameters on the flow and heat transfer is analyzed in detail through plotted graphs.
7
Content available Unsteady MHD mixed convection flow of a micropolar fluid over a vertical wedge
Roy N. C., Gorla R. S. R.
International Journal of Applied Mechanics and Engineering
|
2017
|
Vol. 22, no. 2
363--391
EN
An analysis is presented to investigate the unsteady magnetohydrodynamic (MHD) mixed convection boundary-layer flow of a micropolar fluid over a vertical wedge in the presence of thermal radiation and heat generation or absorption. The free-stream velocity and surface temperature are assumed to be oscillating in magnitude but not in the direction of the oncoming flow velocity. The governing equations have been solved by two distinct methods, namely, the finite difference method for the entire frequency range, and the series solution for low frequency range and the asymptotic series expansion method for the high frequency range. Numerical solutions provide a good agreement with the series solutions. The amplitudes of skin friction and couple stress coefficients are found to be strongly dependent on the Richardson number and the vortex viscosity parameter. The Prandtl number, the conduction-radiation parameter, the surface temperature parameter and the pressure gradient parameter significantly affect the amplitudes of skin friction, couple stress and surface heat transfer rates. However, the amplitudes of skin friction coefficient are considerably affected by the magnetic field parameter, whereas the amplitudes of heat transfer rate are appreciably changed with the heat generation or absorption parameter. In addition, results are presented for the transient skin friction, couple stress and heat transfer rate with the variations of the Richardson number, the vortex viscosity parameter, the pressure gradient parameter and the magnetic field parameter.
8
Content available Role of slip velocity in a magneto-micropolar fluid flow from a radiative surface with variable permeability: a numerical study
Sharma B. K., Tailor V., Goyal M.
International Journal of Applied Mechanics and Engineering
|
2017
|
Vol. 22, no. 3
637--651
EN
An analysis is presented to describe the hydromagnetic mixed convection flow of an electrically conducting micropolar fluid past a vertical plate through a porous medium with radiation and slip flow regime. A uniform magnetic field has been considered in the study which absorbs the micropolar fluid with a varying suction velocity and acts perpendicular to the porous surface of the above plate. The governing non-linear partial differential equations have been transformed into linear partial differential equations, which are solved numerically by applying the explicit finite difference method. The numerical results are presented graphically in the form of velocity, micro-rotation, concentration and temperature profiles, the skin-friction coefficient, the couple stress coefficient, the rate of heat and mass transfers at the wall for different material parameters.
9
Content available Squeeze flow modeling with the use of micropolar fluid theory
Kucaba-Piętal A.
Bulletin of the Polish Academy of Sciences. Technical Sciences
|
2017
|
Vol. 65, nr 6
927--933
EN
The aim of this paper is to study the applicability of micropolar fluid theory to modeling and to calculating tribological squeeze flow characteristics depending on the geometrical dimension of the flow field. Based on analytical solutions in the lubrication regime of squeeze flow between parallel plates, calculations of the load capacity and time required to squeeze the film are performed and compared – as a function of the distance between the plates – for both fluid models: the micropolar model and the Newtonian model. In particular, maximum distance between the plates for which the micropolar effects of the fluid become significant will be established. Values of rheological constants of the fluids, both those experimentally determined and predicted by means of using equilibrium molecular dynamics, have been used in the calculations. The same analysis was performed as a function of dimensionless microstructural parameters.
10
Content available Boundary layer flow of magneto-micropolar nanofluid flow with Hall and ion-slip effects using variable thermal diffusivity
Bilal M., Hussain S., Sagheer M.
Bulletin of the Polish Academy of Sciences. Technical Sciences
|
2017
|
Vol. 65, nr 3
383--390
EN
In the present article, magneto-micropolar nanofluid flow with suction or injection in a porous medium over a stretching sheet for the heat and mass transfer is analyzed numerically. Both Hall and ion-slip effects are considered along with variable thermal diffusivity. The governing partial differential equations are transformed to ordinary differential equations using usual similarity transformations. These coupled non-linear differential equations are solved using the shooting method. Effects of prominent parameter on velocities, temperature and concentration are discussed graphically. Numerical values of skin-friction coefficient, local Nusselt number and local Sherwood number are also tabulated and discussed.
11
Content available On axisymmetrical boundary problem of unsteady motion of micropolar fluid in the half-space
El-Sirafy I. H., Aboutahoun A. W.
Bulletin of the Polish Academy of Sciences. Technical Sciences
|
2016
|
Vol. 64, nr 1
51--62
EN
The aim of this paper is developing an exact solution for the problem of axisymmetrical flow of unsteady motion of micropolar fluid in the half-space when the shear stresses are given on the boundary. The Laplace-Hankel transform technique is used to solve this problem. Some physical quantities such as velocities, pressure and microrotations are obtained and illustrated numerically.
12
Content available Unsteady natural convection in micropolar nanofluids
Rup K., Nering K.
Archives of Thermodynamics
|
2014
|
Vol. 35, no. 3
155--170
EN
This paper presents the analysis of momentum, angular momentum and heat transfer during unsteady natural convection in micropolar nanofluids. Selected nanofluids treated as single phase fluids contain small particles with diameter size 10-38.4 nm. In particular three water-based nanofluids were analyzed. Volume fraction of these solutions was 6%. The first of the analyzed nanofluids contained TiO2 nanoparticles, the second one contained Al2O3 nanoparticles, and the third one the Cu nanoparticles.
13
Content available Effects of chemical reaction on magneto-micropolar fluid flow from a radiative surface with variable permeability
Sharma B. K., Singh A. P., Yadav K., Chaudhary R. C.
International Journal of Applied Mechanics and Engineering
|
2013
|
Vol. 18, no. 3
833--851
EN
This paper presents a study of a hydromagnetic free convection flow of an electrically conducting micropolar fluid past a vertical plate through a porous medium with a heat source, taking into account the homogeneous chemical reaction of first order. A uniform magnetic field has also been considered in the study which acts perpendicular to the porous surface of the above plate. The analysis has been done by assuming varying permeability of the medium and the Rosseland approximation has been used to describe the radiative heat flux in the energy equation. Numerical results are presented graphically in the form of velocity, micro- rotation, concentration and temperature profiles, the skin-friction coefficient, the couple stress coefficient, the rate of heat and mass transfers at the wall for different material parameters. The study clearly demonstrates how a chemical reaction influences the above parameters under given conditions.
14
Content available remote The effect of thermal relaxation times on wave propagation of a micropolar thermoelastic medium with voids due to various sources
Othman M. I. A., Lotfy K.
International Journal of Applied Mechanics and Engineering
|
2011
|
Vol. 16, no 3
791-807
EN
A model of the equations of a two-dimensional problem with the deformation of a micropolar generalized thermoelastic medium with voids under the influence of various sources is formulated in the context of the Lord-Shulman, Green-Lindsay theories, as well as the classical dynamical coupled theory. The normal mode analysis is used to obtain the exact expressions of the displacement components, force stress, coupled stress, change in volume fraction field and temperature distribution. Numerical results are given and illustrated graphically when the volume source is applied. Comparisons are made with the results predicted by the three theories in the presence and absence of material constants due to voids.
15
Content available remote Propagation of waves in a micropolar transversely isotropic generalized thermoelastic half-space
Kumar R., Gupta R. R.
International Journal of Applied Mechanics and Engineering
|
2011
|
Vol. 16, no 3
671-681
EN
Rayleigh waves in a half-space exhibiting microplar transversely isotropic generalized thermoelastic properties based on the Lord-Shulman (L-S), Green and Lindsay (G-L) and Coupled thermoelasticty (C-T) theories are discussed. The phase velocity and attenuation coefficient in the previous three different theories have been obtained. A comparison is carried out of phase velocity, attenuation coefficient and specific loss as calculated from the different theories of generalized thermoelasticity along with the comparison of anisotropy. The amplitudes of displacements, microrotation, stresses and temperature distribution are also obtained. The results obtained and the conclusions drawn are discussed numerically and illustrated graphically. Relevant results of previous investigations are deduced as special cases.
16
Content available remote Mixed convection flow of micropolar fluid in a vertical channel with symmetric and asymmetric wall heating conditions
Umavathi J. C., Prathap Kumar J.
International Journal of Applied Mechanics and Engineering
|
2011
|
Vol. 16, no 1
141-159
EN
The theory of micro polar fluids due to Eringen is used to formulate a set of equations for the mixed convective flow and heat transfer in a vertical channel. The two boundaries of the channel are kept either at equal or at different temperatures. Through a proper choice of non-dimensional variables and parameters, the governing equations are developed and three types of thermal boundary conditions are prescribed. These thermal boundaries are isothermal-isothermal, isoflux-isothermal and isothermal-isoflux for the left-right walls of the channel. Exact analytical solutions are obtained for the velocity and temperature fields for heat generation/absorption conditions. It is found that the material and source/sink parameters have significant effects on the flow. A parametric study is conducted and the results are presented and discussed. By making the Newtonian solvent more and more micropolar, it is possible to obtain drag reduction.
17
Content available remote Effect of thermal stratification on MHD free convection flow of a micropolar fluid over a stretching surface
Mahdy A.
International Journal of Applied Mechanics and Engineering
|
2011
|
Vol. 16, no 3
763-773
EN
This paper analyses the flow and heat transfer characteristics of free convection in the boundary layer flow of a micropolar fluid past a stretching surface with magnetic field, thermal stratification, and heat generation or absorption effects. A similarity transformation was employed to change the governing momentum, angular momentum, and energy partial differential equations into ordinary ones. Then the numerical solution of the problem is derived using the Runge-Kutta Gill method. The sheet is linearly stretched in the presence of a uniform free stream of constant velocity. Numerical results are shown in a tabular form and graphically for the velocity, angular velocity, and temperature as well as the skin-friction and wall heat transfer rate and discussed for various physical parametric values.
18
Content available remote On thermal convection in micropolar fluids in presence of suspended particles
Mohan H., Kumar P., Anjula
Studia Geotechnica et Mechanica
|
2002
|
Vol. 24, nr 3-4
53--63
PL
Opisano niestabilność termiczną płynów mikropolamych w obecności cząstek zawieszonych. Sprzężenie między ruchem wirowym a strumieniami ciepła może być przyczyną nadstabilnych stanów w układzie. Zawieszone cząstki wprowadzają także drgania w układzie, a wartość liczby Rayleigha zmniejsza się ze zwiększeniem liczby cząstek zawieszonych.
EN
The thermal instability of micropolar fluids in the presence of suspended particles has been considered. The coupling between spin and heat fluxes may bring overstable modes in the system. The suspended particles also introduce oscillatory modes in the system and the Rayleigh number is found to decrease with the increase in suspended particles.
19
Content available remote Effects of the characteristic parameters of micropolar flows in a micro-slot between rotating surfaces of revolution
Kim Y. J., Choi G. W., Walicka A., Walicki E.
International Journal of Applied Mechanics and Engineering
|
2002
|
Vol. 7, Spec. is
81-86
EN
Micron-size mechanical devices are becoming more prevalent, both in commercial applications and in scientific inquiry. Within the last decade, a dramatic increase in research activities has taken place, mostly due to the rapidly expanding growth of applications in areas of MEMS, bioengineering, chemical systems, and advanced energy systems. The effects of vortex viscosity variation on the flow fields in a micro-slot between the rotating surfaces of revolution are studied, using a micropolar fluid theory. In order to solve this problem, we have used boundary layer equations and applied non-zero values of the micro-rotation vector on the wall. The results are compared with the corresponding flow problems for Newtonian fluid. Results show that the coefficient d, the ratio of the vortex viscosity coefficient to the shear viscosity coefficient, has an important effect on the streamwise velocity . Also, the coefficient m, a combination of vortex and spin gradient viscosity coefficients, controls the main part of micro-rotation component.
20
Content available remote Effect of homogeneous chemical reaction on solutal analog of Rayleigh-Benard convection in a micropolar fluid
Siddheshwar P. G., Desseaux A.
International Journal of Applied Mechanics and Engineering
|
2002
|
Vol. 7, no 2
513-525
EN
The solutal analog of the Rayleigh-Benard convection in a reactive micropolar fluid is studied numerically using the Rayleigh-Ritz method. The solute concentration is assumed to disappear at a rate which is linearly proportional to the concentration. It is observed that the critical solutal Rayleigh number for this fluid system with homogeneous kinetics is greater than that of a non-reactive fluid system. The results have possible industrial applications.
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