MIXED CONVECTION WITH OPPOSING BUOYANCY AROUND A PAIR OF SIDE-BY-SIDE CYLINDERS IN THE VERTICAL DOMAIN

Abstract

Mixed-convection flow and heat transfer of Newtonian fluids over a pair of side-by-side circular cylinders in opposing buoyancy are investigated numerically. The calculations are performed in an unconfined domain for the following range of physical control parameters: Reynolds number (Re) = 10-50, Richardson number (RI) = 0 to -0.5 for a transverse gap ratio of 1.5 at a constant Prandtl number (Pr) of 0.7 for Newtonian fluids. Extensive numerical results are presented, such as total drag coefficients, average Nusselt number, streamline flow and static temperature contours. The flow is symmetric around a pair of circular cylinders when the flow is governed by forced convection phenomena and asymmetric in the case of opposing buoyancy. The crowding of isotherm around the cylinders is found out to be more at higher values of Re which indicates the rate of heat transfer increases with Re values. The overall drag coefficient and its components increases with the Richardson number at every value of Reynolds numbers and the average Nusselt number increases with an increase in both the Reynolds and Richardson numbers. It is observed that opposing buoyancy decreases heat-transfer characteristics with compare to that of forced convection conditions.