scholarly journals Mixed Convection Flow of Magnetic Viscoelastic Polymer from a Nonisothermal Wedge with Biot Number Effects

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
S. Abdul Gaffar ◽  
V. Ramachandra Prasad ◽  
Bhuvana Vijaya ◽  
O. Anwar Beg
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Mixed Convection ◽  
Biot Number ◽  
Fluid Model ◽  
Numerical Code ◽  
Convection Flow ◽  
Local Skin ◽  
Local Skin Friction ◽  
Layer Flow

Magnetic polymers are finding increasing applications in diverse fields of chemical and mechanical engineering. In this paper, we investigate the nonlinear steady boundary layer flow and heat transfer of such fluids from a nonisothermal wedge. The incompressible Eyring-Powell non-Newtonian fluid model is employed and a magnetohydrodynamic body force is included in the simulation. The transformed conservation equations are solved numerically subject to physically appropriate boundary conditions using a second-order accurate implicit finite difference Keller Box technique. The numerical code is validated with previous studies. The influence of a number of emerging nondimensional parameters, namely, the Eyring-Powell rheological fluid parameter (ε), local non-Newtonian parameter based on length scale (δ), Prandtl number (Pr), Biot number (γ), pressure gradient parameter (m), magnetic parameter (M), mixed convection parameter (λ), and dimensionless tangential coordinate (ξ), on velocity and temperature evolution in the boundary layer regime is examined in detail. Furthermore, the effects of these parameters on surface heat transfer rate and local skin friction are also investigated.

scholarly journals Transient Mixed Convection Flow of A Second-Grade Visco-Elastic Fluid over a Vertical Surface

2008 ◽  
Vol 13 (2) ◽  
pp. 169-179 ◽  
Author(s):  
R. A. Damseh ◽  
A. S. Shatnawi ◽  
A. J. Chamkha ◽  
H. M. Duwairi
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Mixed Convection ◽  
Transfer Problem ◽  
Convection Heat Transfer ◽  
Convection Flow ◽  
Convection Heat ◽  
Local Skin ◽  
Special Cases ◽  
Mixed Convection Heat Transfer

The viscoelastic boundary layer flow and mixed convection heat transfer near a vertical isothermal surface have been examined in this paper. The governing equations are formulated and solved numerically using an explicit finite difference technique. The velocity and temperature profiles, boundary layer thicknesses, Nusselt numbers and the local skin friction coefficients are shown graphically for different values of the viscoelsatic parameter. In general, it is found that the velocity decreases inside the boundary layer as the viscoelsatic parameter is increased and consequently, the local Nusselt number decreases. This is due to higher tensile stresses between viscoelsatic fluid layers which has a retardation effects on the motion of these layers and consequently, on the heat transfer rates for the mixed convection heat transfer problem under investigation. A Comparison with available published results on special cases of the problem shows excellent agreement.

Viscous dissipation effect on mixed convection flow of a micropolar fluid over an exponentially stretching sheet

2009 ◽  
Vol 87 (4) ◽  
pp. 359-368 ◽  
Author(s):  
Mohamed Abd El-Aziz
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Mixed Convection ◽  
Viscous Dissipation ◽  
Convective Transport ◽  
Convection Flow ◽  
Local Similarity ◽  
Mixed Convection Flow ◽  
Local Skin ◽  
Exponential Stretching

Micropolar boundary-layer flow and heat transfer characteristics associated with a heated exponential stretching continuous sheet being cooled by a mixed convection flow are examined. The relevant heat transfer mechanisms are of interest in a wide variety of practical applications such as hot rolling, continuous casting, extrusion, and drawing. The wall temperature and stretching velocity are assumed to vary according to specific exponential forms. The contributions of buoyancy along with viscous dissipation on the convective transport in the boundary-layer region is analyzed in the opposing and assisting flow situations. Local similarity solutions are obtained for the boundary-layer equations governing the problem. A parametric study of the mixed convection parameter ξ, the micropolar parameter Δ, the Eckert number Ec, the parameter of temperature distribution n, and Prandtl number Pr is conducted and a representative set of numerical results for the velocity, angular velocity, temperature profiles, local skin friction coefficient, wall couple stress parameter, and local Nusselt number are illustrated graphically to show typical trends of the solutions.

scholarly journals MHD Mixed Convection Flow of Viscoelastic Fluid Embedded in Porous Medium

2013 ◽  
Vol 9 (1) ◽  
Author(s):  
A.R.M. Kasim ◽  
N.F. Mohammad ◽  
Aurangzaib Aurangzaib ◽  
S. Shafie
Keyword(s):  
Porous Medium ◽  
Mixed Convection ◽  
Viscoelastic Fluid ◽  
Convection Flow ◽  
Convection Boundary Layer ◽  
Local Skin ◽  
Viscoelastic Parameter ◽  
Keller Box Method ◽  
Local Skin Friction ◽  
Layer Flow

An analysis has been carried out to investigate the effect of magnetic field presence on the mixed convection boundary layer flow of viscoelastic fluid over a horizontal circular cylinder in a porous medium. The governing non-similar partial differential equations are transformed into dimensionless forms and then solved numerically using the Keller-box method. Some important parameters have been discussed in this study which include the Prandtl number (Pr), magnetic parameter (M), viscoelastic parameter (K), porosity parameter (γ) and the mixed convection parameters (λ). The results show the values of the velocity decrease when the value of viscoelastic parameter increase and the reverse trend were observe for temperature profile. Numerical results of local skin friction as well as local Nusselt number are also presented in tabular form.

scholarly journals A Multi-Domain Bivariate Approach for Mixed Convection in a Casson Nanofluid with Heat Generation

2018 ◽  
Vol 16 (9) ◽  
pp. 681-699
Author(s):  
Ibukun Sarah OYELAKIN ◽  
Sabyasachi MONDAL ◽  
Precious SIBANDA ◽  
Sandile Sydney MOTSA
Keyword(s):  
Mixed Convection ◽  
Heat Generation ◽  
Fluid Model ◽  
Linearization Method ◽  
Convection Flow ◽  
Transfer Coefficients ◽  
Local Skin ◽  
Casson Nanofluid ◽  
Method Of Solution ◽  
Local Skin Friction

We study the mixed convection flow of a Casson nanofluid past a permeable moving flat plate with heat generation, chemical reaction and viscous dissipation effects in the presence of thermo and thermal diffusion effects. The fluid model described assumes the nanoparticle flux at the boundary is zero, and suction effects on the velocity boundary are accounted for. The system of partial differential equations obtained is solved using a multi-domain bivariate quasi-linearization method with a detailed description of the numerical method of solution. The effects of various fluid parameters on the velocity, temperature, and nanoparticle concentration profiles, as well as on the local skin friction, and heat and mass transfer coefficients, are discussed in detail.

Effect of Nanofluid on Heat Transfer Enhancement for Mixed Convection Flow Over a Corrugated Surface

2020 ◽  
Vol 45 (4) ◽  
pp. 373-383
Author(s):  
Nepal Chandra Roy ◽  
Sadia Siddiqa
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Nusselt Number ◽  
Mixed Convection ◽  
Local Nusselt Number ◽  
Richardson Number ◽  
Thermal Boundary Layer ◽  
Volume Fraction ◽  
Convection Flow ◽  
Mixed Convection Flow

AbstractA mathematical model for mixed convection flow of a nanofluid along a vertical wavy surface has been studied. Numerical results reveal the effects of the volume fraction of nanoparticles, the axial distribution, the Richardson number, and the amplitude/wavelength ratio on the heat transfer of Al2O3-water nanofluid. By increasing the volume fraction of nanoparticles, the local Nusselt number and the thermal boundary layer increases significantly. In case of \mathrm{Ri}=1.0, the inclusion of 2 % and 5 % nanoparticles in the pure fluid augments the local Nusselt number, measured at the axial position 6.0, by 6.6 % and 16.3 % for a flat plate and by 5.9 % and 14.5 %, and 5.4 % and 13.3 % for the wavy surfaces with an amplitude/wavelength ratio of 0.1 and 0.2, respectively. However, when the Richardson number is increased, the local Nusselt number is found to increase but the thermal boundary layer decreases. For small values of the amplitude/wavelength ratio, the two harmonics pattern of the energy field cannot be detected by the local Nusselt number curve, however the isotherms clearly demonstrate this characteristic. The pressure leads to the first harmonic, and the buoyancy, diffusion, and inertia forces produce the second harmonic.

Non-uniform mass transfer in MHD mixed convection flow of water over a sphere with variable viscosity and Prandtl number

2016 ◽  
Vol 26 (7) ◽  
pp. 2235-2251 ◽  
Author(s):  
J. Rajakumar ◽  
P. Saikrishnan ◽  
A. Chamkha
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Mixed Convection ◽  
Skin Friction ◽  
Variable Viscosity ◽  
Skin Friction Coefficient ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Content Type ◽  
Slot Suction

Purpose The purpose of this paper is to consider axisymmetric mixed convection flow of water over a sphere with variable viscosity and Prandtl number and an applied magnetic field. Design/methodology/approach The non-similar solutions have been obtained from the origin of the streamwise co-ordinate to the point of zero skin friction using quasilinearization technique with an implicit finite-difference scheme. Findings The effect of M is not notable on the temperature and heat transfer coefficient when λ is large. The skin friction coefficient and velocity profile are enhance with the increase of MHD parameter M when λ is small. Viscous dissipation has no significant on the skin friction coefficient under MHD effect. For M=1, the movement of the slot or slot suction or slot injection do not cause any effect on flow separation. The slot suction and the movement of the slot in downstream direction delay the point of zero skin friction for M=0. Originality/value The present results are original and new for water boundary-layer flow over sphere in mixed convection flow with MHD effect and non-uniform mass transfer. So this study would be useful in analysing the skin friction and heat transfer coefficient on sphere of mixed convection flow of water boundary layer with MHD effect.

scholarly journals Effects of Slip and Heat Generation/Absorption on MHD Mixed Convection Flow of a Micropolar Fluid over a Heated Stretching Surface

2010 ◽  
Vol 2010 ◽  
pp. 1-20 ◽  
Author(s):  
Mostafa Mahmoud ◽  
Shimaa Waheed
Keyword(s):  
Nusselt Number ◽  
Friction Coefficient ◽  
Mixed Convection ◽  
Skin Friction ◽  
Heat Generation ◽  
Local Nusselt Number ◽  
Skin Friction Coefficient ◽  
Convection Flow ◽  
Local Skin ◽  
Local Skin Friction

A theoretical analysis is performed to study the flow and heat transfer characteristics of magnetohydrodynamic mixed convection flow of a micropolar fluid past a stretching surface with slip velocity at the surface and heat generation (absorption). The transformed equations solved numerically using the Chebyshev spectral method. Numerical results for the velocity, the angular velocity, and the temperature for various values of different parameters are illustrated graphically. Also, the effects of various parameters on the local skin-friction coefficient and the local Nusselt number are given in tabular form and discussed. The results show that the mixed convection parameter has the effect of enhancing both the velocity and the local Nusselt number and suppressing both the local skin-friction coefficient and the temperature. It is found that local skin-friction coefficient increases while the local Nusselt number decreases as the magnetic parameter increases. The results show also that increasing the heat generation parameter leads to a rise in both the velocity and the temperature and a fall in the local skin-friction coefficient and the local Nusselt number. Furthermore, it is shown that the local skin-friction coefficient and the local Nusselt number decrease when the slip parameter increases.

Radiation effect on natural convection boundary layer flow over a vertical wavy frustum of a cone

2009 ◽  
Vol 223 (7) ◽  
pp. 1605-1614 ◽  
Author(s):  
M M Molla ◽  
M A Hossain ◽  
R S R Gorla
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Natural Convection ◽  
Boundary Layer Flow ◽  
Average Rate ◽  
Local Heat Transfer ◽  
Convection Boundary Layer ◽  
Local Skin ◽  
Wide Range ◽  
Layer Flow

The effect of thermal radiation on a steady two-dimensional natural convection laminar boundary layer flow of a viscous incompressible optically thick fluid over a vertical wavy frustum of a cone has been investigated. The boundary layer regime when the Grashof number Gr is large is considered. Using appropriate transformations, the basic governing equations are transformed into a dimensionless form and then solved numerically employing two efficient methods, namely: (a) implicit finite difference method together with Keller-box scheme and (b) direct numerical scheme. Numerical results are presented by streamline, isotherms, velocity and temperature distribution of the fluid, as well as the local shearing stress in terms of the local skin-friction coefficient, the local heat transfer rate in terms of local Nusselt number, and the average rate of heat transfer for a wide range of the radiation—conduction parameter or Planck number Rd and the surface heating parameter θw.

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