Mixed convection in poiseuille fluid from an asymmetrically confined heated circular cylinder

Abstract

This paper examines the effects of thermal buoyancy on momentum and heat transfer characteristics of symmetrically and asymmetrically confined cylinder submerged in incompressible Poiseuille liquid. The detailed flow and temperature fields are visualized in term of streamlines and isotherm contours. The numerical results have been presented and discussed for the range of conditions as 10 ? Re ? ? 40, Richardson number 0 ? Ri ? 4, and eccentricity factor 0 ? ? ? 0.7 at Prandtl number Pr = 1, and blockage ratio B = 20%. The representative streamlines and isotherm patterns are presented to interpret the flow and thermal transport visu?alization. When the buoyancy is added, it is observed that the flow separation di?minishes gradually and at some critical value of the thermal buoyancy parameter it completely disappears resulting a creeping flow. Additionally, it is observed that the down vortex requires more heating in comparison to upper vortex in order to be suppressed. In the range 1.5 ? Ri ? 4, two counter rotating regions appear above the cylinder and on the down channel wall behind the cylinder. The total drag coefficient, CD, increases with increasing Richardson number at (? = 0). Moreover, an increase in eccentricity factor from 0 to 0.3 increases CD by 37% at Re = 10, and 30% at Re = 20 for Ri = 4. An increase in eccentricity factor form 0 to 0.4 increases local Nusselt number by 20.4% at Re = 10, and 18.6% at Re = 30 for Ri = 4.