Abstract
The aim of this paper is to study the thermal radiation effects on the flow and heat transfer of an unsteady magnetohydrodynamic (MHD) micropolar fluid over a vertical heated nonisothermal stretching surface in the presence of a strong nonuniform magnetic field. The symmetries of the governing partial differential equations are de- termined by the two-parameter group method. One of the resulting systems of reduced nonlinear ordinary differential equations are solved numerically by the Chebyshev spec- tral method. The effects of various parameters on the velocity, the angular velocity, and the temperature profiles as well as the skin-friction coefficient, the wall couple stress co- efficient, and the Nusselt number are studied.
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Abbreviations
- B :
-
applied magnetic field
- T c :
-
characteristic temperature
- C f :
-
skin-friction coefficient
- t :
-
time
- c p :
-
specific heat at constant pressure
- U 0 :
-
characteristic velocity
- e bλ :
-
Plank’s function
- u, v :
-
velocities along the x- and y-axes
- Re :
-
Reynolds number
- r :
-
radiation parameter
- Pr :
-
Prandtl number
- T :
-
dimensional temperature
- f :
-
dimensionless stream function
- (x,y):
-
Cartesian coordinate
- g :
-
gravitational acceleration
- I :
-
dimensionless angular velocity
- ζ:
-
ratio of the gyration vector component to the fluid shear at a solid boundary
- j :
-
microinertia density
- K :
-
material parameter
- β :
-
thermal expansion coefficient
- K λ :
-
absorption coefficient
- κ :
-
thermal conductivity
- L :
-
characteristic length
- ν :
-
kinematic viscosity
- M :
-
magnetic parameter
- ρ :
-
fluid density
- m w :
-
wall couple stress
- γ 0 :
-
spin gradient viscosity
- m 0 :
-
microrotation parameter
- µ:
-
dynamic viscosity
- N :
-
angular velocity
- α :
-
thermal diffusivity
- Nu :
-
Nusselt number
- θ:
-
dimensionless temperature
- q r :
-
thermal radiation flux
- ψ :
-
stream function
- k :
-
vortex viscosity
- ′:
-
differentiation with respect to η
- w:
-
wall condition
- ∞:
-
free stream condition
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Hassanien, I.A., El-Hawary, H.M., Mahmoud, M.A.A. et al. Thermal radiation effect on flow and heat transfer of unsteady MHD micropolar fluid over vertical heated nonisothermal stretching surface using group analysis. Appl. Math. Mech.-Engl. Ed. 34, 703–720 (2013). https://doi.org/10.1007/s10483-013-1701-6
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DOI: https://doi.org/10.1007/s10483-013-1701-6