On the effects of orientation on flow and heat transfer from a semi-circular cylinder near a stationary wall

Abstract

Numerical analysis of flow and forced convection heat transport from a two-dimensional semi-circular cylinder placed near a stationary wall is presented. The uniformly heated cylinder is within the boundary layer of the plane wall and is subjected to linear shear flow. An unsteady flow of incompressible Newtonian fluid around the cylinder is studied assuming constant properties. Two different orientations of the cylinder, i.e. the curved and flat surfaces exposed to the incoming flow, are considered, and the results are compared with those of a circular cylinder. The cylinder-to-wall gap ratio (G/D.) values are varied between 0.1 and 0.5, and the Reynolds number range of 100 ≤ Re ≤ 200 is considered. Numerical experiments are performed using Ansys Fluent. Results suggest that the presence of a stationary wall influences both the flow and thermal fields significantly. A decrement in the drag coefficient and average Nusselt number values is reported, while the lift coefficient and Strouhal number increase, resulting from shear layers' interaction in the gap between cylinder and wall. The heat transfer enhancement ratio is higher for the flow past curved forebody than the flat forebody configuration and circular cylinder. Mean Nusselt number correlations for the range of parameters considered in the present study are provided. © 2021 The Authors. Published by Elsevier Ltd.