Effect of Sinusoidal Cylinder inside a Lid-driven Square Enclosure on Mixed Convection

This study investigated the effects of the Reynolds number and wavelength of the sinusoidal cylinder on mixed convection in a lid-driven enclosure. The Reynolds numbers considered were 100, 500, and 1000, whereas the wavelengths of the sinusoidal cylinder considered were 1, 2, and 3, respectively. The heat and vortical structures, volume-averaged orthogonal entropy, and time and surface-averaged Nusselt numbers were investigated by increasing the Reynolds number and the wavelengths. At Reynolds numbers of 100 and 500, the time- and surface-averaged Nusselt numbers at the bottom wall increased as the circular cylinder changed to the sinusoidal cylinder. Further, the heat transfer performance of the sinusoidal cylinder with a wavelength of 3 for 100 and 500 Reynolds numbers were 16.8% and 20.2%, respectively, which were larger than those of a circular cylinder. At the Reynolds number of 1000, the time- and surface-averaged Nusselt numbers at the bottom of the sinusoidal cylinder decreased. Further, the heat transfer performance of the sinusoidal cylinder was 4.9%, which was smaller than that of the circular cylinder.