A comprehensive numerical study was conducted to examine the heat transfer characteristics of a heated cylinder immersed in aqueous nanofluids. The aim of this analysis is to analyze the impact of confinement and other relevant dimensionless parameters on heat transfer. In this study, Al2O3 has been used as the nanoparticle having diameter of 80 nm suspended in base fluids, i.e., water. In order to study the changing of characteristics with temperature, this study utilizes temperature-dependent equations to describe the viscosity and thermal conductivity of nanofluids. Several studies have been conducted to investigate the streamline plot, isotherm contour, drag coefficient (CD), lift force (CL), and average Nusselt number (Nu) in order to comprehend the impact of the Peclet number (Pe), nanoparticle volume fraction (ϕ), roughness (ε), confinement factor (λ), and rotation (α) for the following range of parameters: Peclet number Pe = 50, roughness 0 ≤ ε ≤ 0.5, rotational velocity α = 0, 5, diameter of particles d = 80 nm, volume fraction of nanoparticles φ = 0.01, and confinement ratio λ = 0.1.