Couple Stress Coefficient Research Articles

Magneto-polar fluid flow through a porous medium of variable permeability in slip flow regime

A theoretical study is carried out to obtain an analytical solution of free convective heat transfer for the flow of a polar fluid through a porous medium with variable permeability bounded by a semi-infinite vertical plate in a slip flow regime. A uniform magnetic field acts perpendicular to the porous surface. The free stream velocity follows an exponentially decreasing small perturbation law. Using the approximate method the expressions for the velocity, microrotation, and temperature are obtained. Further, the results of the skin friction coefficient, the couple stress coefficient and the rate of heat transfer at the wall are presented with various values of fluid properties and flow conditions.

Passive control of nanoparticle of micropolar fluid past a stretching sheet with nanoparticles, convective boundary condition and second-order slip

This article deals with a second-order slip flow and magnetic field on boundary layer flow of micropolar fluid past a stretching sheet. Situation of nil normal flux of nanoparticles at the wall for the stretching flow is taken into account. By employing appropriate similarity transformation and non-dimensional variables, the governing non-linear boundary-value problems were reduced into coupled higher order non-linear ordinary differential equation. Then, numerical solution for velocity, angular velocity (microrotation), temperature, and concentration has been established. The equations were numerically solved using the function bvp4c from the matlab software for different values of governing parameters. Numerical results have been obtained and discussed for non-dimensional velocity, temperature, microrotation, the skin friction coefficient, and local Nusselt number using some fixed values of the governing parameters. The results indicate that the skin friction coefficient Cf increases as the values of slip parameter γ increase. However, the local Nusselt number − [Formula: see text] increases as thermophoresis parameter Nt, microrotation parameter β, and convective parameter Bi increase. The wall couple stress coefficient decreases as the values of governing parameters such as magnetic parameter M, material parameter β, and for both slip parameters γ and δ increase. A comparison with earlier investigations available in the literature has been done and an excellent agreement is achieved.

Perturbation analysis of magnetohydrodynamics oscillatory flow on convective-radiative heat and mass transfer of micropolar fluid in a porous medium with chemical reaction

This paper deals with the perturbation analysis of mixed convection heat and mass transfer of an oscillatory viscous electrically conducting micropolar fluid over an infinite moving permeable plate embedded in a saturated porous medium in the presence of transverse magnetic field. Analytical solutions are obtained for the governing basic equations. The effects of permeability, chemical reaction, viscous dissipation, magnetic field parameter and thermal radiation on the velocity distribution, micro-rotation, skin friction and wall couple stress coefficients are analyzed in detail. The results indicate that the effect of increasing the chemical reaction has a tendency to decrease the skin friction coefficient at the wall, while opposite trend is seen by increasing the permeability parameter of the porous medium. Also micro-rotational velocity distribution increases with an increase in the magnetic field parameter.

MHD micropolar fluid flow with thermal radiation and thermal diffusion in a rotating frame

This work is devoted to investigate the influences of thermal radiation and thermal diffusion on hydromagnetic free convection heat and mass transfer flow of a micropolar fluid with constant wall heat and mass transfer in a porous medium bounded by a semi-infinite porous plate in a rotating frame of reference. The dimensionless governing equations for this investigation are solved analytically using small perturbation approximation. With the help of graphs, the effects of the various important parameters entering into the problem on the velocity, microrotation, temperature, and concentration fields within the boundary layer are separately discussed. Finally the effects of the pertinent parameters on the skin friction coefficient, couple stress coefficient, Nusselt number, and Sherwood number at the wall are presented numerically in tabular form. In addition, the results obtained show that these parameters have significant influence on the flow, heat and mass transfer.

Combined Influence of Hall Current and Soret Effect on Chemically Reacting Magnetomicropolar Fluid Flow from Radiative Rotating Vertical Surface with Variable Suction in Slip-Flow Regime.

An analysis study is presented to study the effects of Hall current and Soret effect on unsteady hydromagnetic natural convection of a micropolar fluid in a rotating frame of reference with slip-flow regime. A uniform magnetic field acts perpendicularly to the porous surface which absorbs the micropolar fluid with variable suction velocity. The effects of heat absorption, chemical reaction, and thermal radiation are discussed and for this Rosseland approximation is used to describe the radiative heat flux in energy equation. The entire system rotates with uniform angular velocity Ω about an axis normal to the plate. The nonlinear coupled partial differential equations are solved by perturbation techniques. In order to get physical insight, the numerical results of translational velocity, microrotation, fluid temperature, and species concentration for different physical parameters entering into the analysis are discussed and explained graphically. Also, the results of the skin-friction coefficient, the couple stress coefficient, Nusselt number, and Sherwood number are discussed with the help of figures for various values of flow pertinent flow parameters.

Effect of thermo diffusion and chemical reaction on convective heat and mass transfer flow of a rotating micro polar fluid with hall effect past a vertical plate

In this paper, we investigate the effect of combined influence of Hall effect chemical reaction thermo diffusion and rotation on Hydro magnetic convective Heat & mass transfer flow of a micro polar fluid through a porous medium bounded by a semi-infinite porous plate in the presence of heat generating sources. The dimensionless grouping equations for this investigation on solved using small perturbation approximation. The effects of various dimensionless parameters entering to the problem on the velocity & temperature concentration micro rotation profiles across the boundary layer are investigated to graphs. Also the result of the couple stress coefficient, the rate of heat & mass transfer at the wall are evaluated for different variations of the parameters.

Unsteady axisymmetric flow of a micropolar fluid between the stretching surfaces

This analysis is carried out to study magnetohydrodynamic (MHD) unsteady two-dimensional axisymmetric flow of micropolar fluid between radially stretching sheets. Ordinary equations are obtained by employing similarity transformations to the partial differential equations in cylindrical coordinates. Series solutions are derived by the homotopy analysis method (HAM). The convergence of the derived series solutions is checked and shown in table. The influence of several parameters on dimensionless velocities is presented through plots. The behavior of skin friction and couple stress coefficients is tabulated against various values of the pertinent parameters.

Effects of Chemical Reaction on Magneto-Micropolar Fluid Flow from a Radiative Surface with Variable Permeability

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

Mass transfer effects on the unsteady mhd radiative– convective flow of a micropolar fluid past a vertical porous plate with variable heat and mass fluxes

The problem of unsteady two-dimensional laminar flow of a viscous incompressible micropolar fluid past a vertical porous plate in the presence of a transverse magnetic field and thermal radiation with variable heat and mass fluxes is considered. The free stream velocity is subjected to exponentially increasing or decreasing small perturbations. A uniform magnetic field acts perpendicularly to a porous surface where a micropolar fluid is absorbed with a suction velocity varying with time. The Rosseland approximation is used to describe radiative heat transfer in the limit of optically thick fluids. The effects of the flow parameters and thermophysical properties on the velocity and temperature fields across the boundary layer are investigated. The effects of various parameters on the velocity, microrotation velocity, temperature, and concentration profiles are given graphically, and the values of the skin friction and couple stress coefficients are presented.

Chemical Reaction Effects on Free Convective Flow of a Polar Fluid from a Vertical Plate with Uniform Heat and Mass Fluxes

This article deals with a study of two dimensional free convective flow of a polar fluid through a porous medium due to combined effects of thermal and mass diffusion in presence of a chemical reaction of first order. The objective of the present investigation is to analyze the free convective flow in the presence of prescribed wall heat flux and mass flux condition. The governing partial differential equations are non- dimensionalized and transformed into a system of non-similar equations. The resulting coupled nonlinear partial differential equations are solved numerically under appropriate transformed boundary conditions using an implicit finite difference scheme in combination with quasilinearisation technique. Computations are performed for a wide range of values of the various governing flow parameters of the velocity, angular velocity, temperature and species concentration profiles and results are presented graphically. The numerical results for local skin friction coefficient, couple stress coefficient, local Nusselt number and local Sherwood number are also presented. The obtained results are compared with previously published work and were to be in excellent agreement. The study reveals that the flow characteristics are profoundly influenced by the polar effects.

Effect of Double Stratification on Mixed Convection in a Micropolar Fluid

The effects of thermal and solutal stratification on mixed convection heat and mass transfer along a vertical plate embedded in a micropolar fluid has been studied. The nonlinear governing equations and their associated boundary conditions are initially cast into dimensionless forms by pseudo - similarity variables. The resulting system of equations is then solved numerically using the Keller-box method. The numerical results are compared and found to be in good agreement with previously published results as special cases of the present investigation. The effect of coupling number, mixed convection parameter and double stratification parameters on local skin-friction and wall couple stress coefficients are discussed. An analysis of the results obtained shows that the flow field is influenced appreciably by coupling number, mixed convection parameter, thermal and solutal stratification parameters. Keywords: Mixed convection; Micropolar fluid; Thermal and Solutal Stratification. 2010 Mathematics Subject Classification: 76R05; 76R10; 76A05; 76N20.

Magnetohydrodynamics and Radiation Effects on Unsteady Convection Flow of Micropolar Fluid Past a Vertical Porous Plate with Variable Wall Heat Flux

An analysis is presented for the problem of the unsteady two-dimensional laminar flow of a viscous incompressible micropolar fluid past a vertical porous plate in the presence of a transverse magnetic field and thermal radiation with variable heat flux. The free stream velocity follows an exponentially increasing or decreasing small perturbation law. A uniform magnetic field acts perpendicularly to the porous surface in which it absorbs the micropolar fluid with a suction velocity varying with time. The Rosseland approximation is used to describe radiative heat transfer in the limit of optically thick fluids. The effects of flow parameters and thermophysical properties on the flow temperature fields across the boundary layer are investigated. The method of solution can be applied for small perturbation approximation. Numerical results of velocity profiles of micropolar fluids are compared with the corresponding flow problems for a Newtonian fluid. Also, the results of the skin-friction coefficient and the couple stress coefficient at the wall are prepared with various values of the fluid properties.

Heat Transfer Analysis on Axisymmetric Mhd Flow of a Micropolar Fluid Between the Radially Stretching Sheets

ABSTRACTThe effect of heat transfer on the axisymmetric flow of MHD micropolar fluid between two radially stretching sheets is described. The governing partial differential equations are reduced into the ordinary differential equations by using transformations. The resulting problems are solved by homotopy analysis method (HAM). Dimensionless velocities and temperature are plotted for the variation of influential parameters. The local skin friction coefficient, local couple stress coefficient and Nusselt number are tabulated with respect to the influence of several physical parameters.

MHD Squeezing Flow of a Micropolar Fluid Between Parallel Disks

The squeezing flow of an incompressible micropolar fluid between two parallel infinite disks is investigated in the presence of a magnetic flied. An analysis of strong and weak interactions has been carried out. Similarity solutions are derived by homotopy analysis method. The variation of dimensionless velocities are sketched in order to see the influence of pertinent parameters. Skin friction coefficient and wall couple stress coefficient have been tabulated. In addition, the derived results are compared with the homotopy perturbation solution in a viscous fluid.

Free convective heat and mass transfer in a doubly stratified non-Darcy micropolar fluid

The flow, heat and mass transfer characteristics of the free convection on a vertical plate with uniform and constant heat and mass fluxes in a doubly stratified micropolar fluid saturated non-Darcy porous medium are studied. The nonlinear governing equations and their associated boundary conditions are initially cast into dimensionless forms by pseudo-similarity variables. The resulting system of equations is then solved numerically using the Keller-box method. The numerical results are compared and found to be in good agreement with previously published results as special cases of the present investigation. The effects of the micropolar, Darcy, non-Darcy and stratification parameters on the dimensionless velocity, microrotation, wall temperature, wall concentration, local skin-friction coefficient and wall couple stress coefficient are presented graphically.

Effect of chemical reaction and thermal radiation on heat and mass transfer flow of MHD micropolar fluid in a rotating frame of reference

This paper studies the effect of first order chemical reaction and thermal radiation on hydromagnetic free convection heat and mass transfer flow of a micropolar fluid via a porous medium bounded by a semi-infinite porous plate with constant heat source in a rotating frame of reference. The plate is assumed to oscillate in time with constant frequency so that the solutions of the boundary layer are the same oscillatory type. The dimensionless governing equations for this investigation are solved analytically using small perturbation approximation. The effect of the various dimensionless parameters entering into the problem on the velocity, temperature and concentration profiles across the boundary layer are investigated through graphs. Also the results of the skin friction coefficient, couple stress coefficient, the rate of heat and mass transfer at the wall are prepared with various values of the parameters.

Axisymmetric magnetohydrodynamic flow of micropolar fluid between unsteady stretching surfaces

This investigation examines the time dependent magnetohydrodynamic (MHD) flow problem of a micropolar fluid between two radially stretching sheets. Both strong and weak concentrations of microelements are taken into account. Suitable transformations are employed for the conversion of partial differential equations into ordinary differential equations. Solutions to the resulting problems are developed with a homotopy analysis method (HAM). The angular velocity, skin friction coefficient, and wall couple stress coefficient are illustrated for various parameters.

Unsteady MHD natural convection from a heated vertical porous plate in a micropolar fluid with Joule heating, chemical reaction and radiation effects

The effects of Joule-heating, chemical reaction and thermal radiation on unsteady MHD natural convection from a heated vertical porous plate in a micropolar fluid are analyzed. The partial differential equations governing the flow and heat and mass transfer have been solved numerically using an implicit finite-difference scheme. The case corresponding to vanishing of the anti-symmetric part of the stress tensor that represents weak concentrations is considered. The numerical results are validated by favorable comparisons with previously published results. A parametric study of the governing parameters, namely the magnetic field parameter, suction/injection parameter, radiation parameter, chemical reaction parameter, vortex viscosity parameter and the Eckert number on the linear velocity, angular velocity, temperature and the concentration profiles as well as the skin friction coefficient, wall couple stress coefficient, Nusselt number and the Sherwood number is conducted. A selected set of numerical results is presented graphically and discussed.

Heat and mass transfer by natural convection in a doubly stratified non-Darcy micropolar fluid

Natural convection heat and mass transfer along a vertical plate embedded in a doubly stratified micropolar fluid saturated non-Darcy porous medium is presented. The governing nonlinear equations are solved numerically using the Keller-box method. The effects of physical parameters on velocity, microrotation, temperature, concentration, local skin friction and wall couple stress coefficient, heat and mass transfer coefficients are illustrated graphically and in tabular form. The results of convection in a micropolar fluid along a vertical plate are obtained as a special case from the present analysis and are found to be in good agreement with the previously published results.

Influence of chemical reaction and thermal radiation on the heat and mass transfer in MHD micropolar flow over a vertical moving porous plate in a porous medium with heat generation

An analysis is presented for the effects of chemical reaction and thermal radiation on hydromagnetic free convection heat and mass transfer for a micropolar fluid via a porous medium bounded by a semi-infinite vertical porous plate in the presence of heat generation. The plate moves with a constant velocity in the longitudinal direction and the free stream velocity follows an exponentially small perturbation law. A uniform magnetic field acts perpendicularly to the porous surface in which absorbs the micropolar fluid with a suction velocity varying with time. Analytical expressions are computed numerically. Numerical calculations are carried out the purpose of the discussion of the results which are shown on graphs and the effects of the various dimensionless parameters entering into the problem on the velocity, angular velocity, temperature, concentration. Also, the results of the skin-friction coefficient, the couple stress coefficient and the rates of the heat and mass transfers at the wall are prepared with various values of fluid properties and the flow conditions are studied.