Effect of time-dependent wall temperature on natural convection of a non-Newtonian fluid in an enclosure

Abstract

This paper presents the results of computational analysis of unsteady natural convection of a non-Newtonian fluid in an enclosure, taking into account the time sinusoidal dependence of the wall temperature. The analysis has been carried out to reveal the dependence of the emerging streamlines, isotherms, average Nusselt number and flow intensity on the controlling parameters such as Rayleigh number (Ra = 104–106), power-law index (n = 0.6–1.4), and side wall temperature oscillation frequency (f = 0.01π–0.05π). The problem has been worked out by the finite difference technique including the successive under-relaxation procedure, the locally one-dimensional Samarskii scheme, and the Thomas algorithm. The results show that a pseudoplastic fluid with high Rayleigh numbers and high oscillation frequencies is more suitable for intensifying the convective heat and mass transfer.