Flow over and forced convection heat transfer in Newtonian fluids from a semi-circular cylinder

Abstract

Momentum and heat transfer characteristics of a semi-circular cylinder immersed in unconfined flowing Newtonian fluids have been investigated numerically. The governing equations, namely, continuity, Navier–Stokes and energy, have been solved in the steady flow regime over wide ranges of the Reynolds number (0.01 ⩽ Re ⩽ 39.5) and Prandtl number ( Pr ⩽ 100). Prior to the investigation of drag and heat transfer phenomena, the critical values of the Reynolds number for wake formation (0.55 < Re c < 0.6) and for the onset of vortex shedding (39.5 < Re c < 40) have been identified. The corresponding values of the lift coefficient, drag coefficient, and Strouhal number are also presented. After establishing the limit of the steady flow regime, the influence of the Reynolds number (0.01 ⩽ Re ⩽ 39.5) and Prandtl number ( Pr = 0.72, 1, 10, 50 and 100) on the global flow and heat transfer characteristics have been elucidated. Detailed kinematics of the flow is investigated in terms of the streamline and vorticity profiles and the variation of pressure coefficient in the vicinity of the cylinder. The functional dependence of the individual and total drag coefficients on the Reynolds number is explored. The Nusselt number shows an additional dependence on the Prandtl number. In addition, the isotherm profiles, local Nusselt number ( Nu L ) and average Nusselt number ( Nu) are also presented to analyze the heat transfer characteristic of a semi-circular cylinder in Newtonian media.