Forced convection in power-law fluids from an asymmetrically confined heated circular cylinder

Abstract

In this work, the influence of asymmetric confinement on momentum and heat transfer characteristics from a heated circular cylinder submerged in power-law liquids has been investigated numerically. The detailed flow and temperature fields are visualized in terms of the streamline and isotherm contours. Due to the asymmetry of the flow field, in addition to the drag force, there is also a net lift force acting on the cylinder. Furthermore, shear-thinning characteristics tend to modulate the influence of blockage and asymmetry on the rate of heat transfer. All else being equal, shear-thinning behaviour facilitates heat transfer. On the other hand, depending upon the degree of asymmetry, the heat transfer may increase or decrease thereby suggesting a non-monotonic relationship between Nusselt number and asymmetric placement of the cylinder. The results reported herein embrace the following ranges of conditions: Reynolds number, 0.1 ⩽ Re ⩽ 100 ; power-law index, 0.3 ⩽ n ⩽ 1 ; Prandtl number, 1 ⩽ Pr ⩽ 100 ; blockage ratio, β = 0.2, 0.3 and 0.4, and gap ratio, 0.25 ⩽ γ ⩽ 1 . The range of Reynolds number is such that the flow is likely to be in the steady and time-periodic flow regime, at least for an unconfined cylinder.