UNSTEADY BUOYANT CONVECTIVE FLOW AND THERMAL TRANSPORT ANALYSIS IN A NONUNIFORMLY HEATED ANNULAR GEOMETRY

The objective of the present paper is to investigate the convective flow and thermal dissipation rate in an annular enclosure subjected to sinusoidal thermal profiles with dissimilar phase deviation and amplitudes on vertical boundary walls and insulated horizontal walls. To solve the model equations, an implicit finite difference scheme with over-relaxation has been implemented. The numerical predictions focus specifically on phase deviation, amplitude ratio, Rayleigh number, and aspect ratio of the annulus on fluid flow behavior, thermal characteristics, and local and average Nusselt numbers. The simulations were performed for an extensive range of nondimensional parameters (10(3) <= Ra <= 10(6), 0 <= epsilon <= 1, 0 <= phi <= pi, and 0.5 <= A <= 2), and it was found that the amplitude ratio plays a key role in enhancing the thermal dissipation rate as compared to other parameters. It has also been noticed that maximum heat dissipation takes place with nonuniform thermal conditions rather than the uniform thermal condition imposed on the cylindrical boundaries. Further, a correlation for thermal dissipation rate has been developed from the vast numerical simulations.