MOMENTUM AND HEAT TRANSFER OF NON-NEWTONIAN FLUIDS AROUND A SQUARE CYLINDER UNDER THE INFLUENCE OF AIDING BUOYANCY

Abstract

Mixed convection flow and heat transfer characteristics of non-Newtonian fluid flowing around a long square cylinder under the influence of aiding buoyancy are investigated in the vertical unconfined configuration for the Reynolds number (Re) = 75 - 150, power-law index (n) = 0.2 - 1 and Richardson number (Ri) = 0 - 1 for a constant Prandtl number (Pr) = 50. The values of both Drag coefficient and Nusselt number increase with Richardson number. Drag coefficient is observed to decrease with increase in Reynolds number but Nusselt number shows an opposite behavior i.e. it increases with Reynolds number. In the present range of conditions, the flow of shear-thinning fluids is truly pseudo-periodic in nature at high Reynolds numbers and/or at small values of power-law index (highly shear-thinning fluids).