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MHD free convection of non-Newtonian power-law fluids over a uniformly heated horizontal plate

ABSTRACT
The magnetohydrodynamic free convection flow of non-Newtonian power-law fluids over a horizontal plate subjected to a constant heat flux is studied. The results are presented for various values of the three influential parameters, i.e. the generalized Hartmann number (Ha*), the generalized Prandtl number (Pr*), and the non-Newtonian power-law viscosity index (n). Increasing the Hartmann number increases the thermal boundary layer thickness and the surface temperature and consequently decreases the wall skin friction and Nusselt number. A lower Pr* results in a larger skin friction coefficient and higher wall temperature as well as thicker thermal boundary layer. The viscosity index (n) is predicted to influence the flow conditions depending on the value of Pr*. At high Pr* numbers, by decreasing n, the wall skin friction, temperature scale, and thermal boundary layer thickness are increased and the Nusselt number is decreased, while the opposite trend is observed for low Pr*. A general correlation for the Nusselt number is derived using the numerical results.
KEYWORDS
PAPER SUBMITTED: 2019-01-02
PAPER REVISED: 2019-03-13
PAPER ACCEPTED: 2019-03-15
PUBLISHED ONLINE: 2019-04-07
DOI REFERENCE: https://doi.org/10.2298/TSCI190102110B
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