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.

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 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.

Periodic momentum and thermal boundary layer mixed convection flow around the surface of a sphere in the presence of viscous dissipation

2017 ◽  
Vol 95 (10) ◽  
pp. 976-986 ◽  
Author(s):  
Muhammad Ashraf ◽  
Almas Fatima ◽  
R.S.R. Gorla
Keyword(s):  
Boundary Layer ◽  
Mixed Convection ◽  
Viscous Dissipation ◽  
Thermal Boundary Layer ◽  
Numerical Solutions ◽  
Numerical Technique ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Implicit Finite Difference ◽  
Convection Parameter

Numerical solutions for the periodic laminar boundary layer mixed convection flow around the surface of a heated sphere in the presence of viscous dissipation have been obtained by solving the governing equations using an implicit finite difference numerical technique. The fluid under consideration is assumed to be viscous and incompressible. Periodic momentum and thermal boundary layer profiles for different positions of x around the surface of the sphere are evaluated. The features of the obtained results for different values of mixed convection parameter λ, Prandtl number Pr, viscous dissipation parameter N, and frequency parameter ω are shown graphically. The obtained results confirm significant effect of all these mentioned parameters on periodic momentum and thermal boundary layer mixed convection flow around different positions of the sphere.

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.

scholarly journals Mixed convection flow and heat transfer in ferromagnetic fluid over a stretching sheet with partial slip effects

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2515-2526 ◽  
Author(s):  
Ahmad Zeeshan ◽  
Aaqib Majeed ◽  
Rahmat Ellahi ◽  
Qazi Zia
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Stretching Sheet ◽  
Velocity Slip ◽  
Partial Slip ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Local Skin ◽  
Flow And Heat Transfer ◽  
Ferromagnetic Fluid

The 2-D steady boundary layer mixed convection flow and heat transfer in ferromagnetic fluid over a stretching sheet is investigated. Velocity slip is taken into account. The governing partial differential equations are first transformed into the non-linear ordinary coupled differential equation using a similarity transformation and then solved numerically by Runge-Kutta-Fehlberg method. The role of local skin friction, heat transfer rate, ferromagnetic-interaction parameter, slip parameter and the buoyancy parameter on velocity and temperature profiles inside the boundary layers are examined through tables and graphically. Finally a comparison is also made with the existing literature and found in good agreement.

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