Effect of the aspect ratio of an elliptical cylinder on mixed convective heat transfer within a lid-driven enclosure

This study examines the mixed convection inside a lid-driven enclosure containing an elliptical cylinder for Reynolds numbers of 100 <= Re <= 1000. A simulation conducted to study the effects of the aspect ratio, and the temperature boundary conditions (theta(cyi)=theta(C)or theta(C)/2) of the elliptical cylinder. The heat transfer performances rely on the relative magnitude of the viscous force caused by the top lid movement. Another factor is the buoyancy force that occurred due to the temperature difference between the heated bottom and the cold top walls, which also strongly depends on the aspect ratio. AtRe= 500, the value of <Nu(B)> increased by about 7.6 % at theta(Cyl)= 0 andAR= 4.00 compared to the results of a circular cylinder (AR= 1.00). Moreover, a correlation has been proposed to estimate the Nusselt nuber for the geiven Reynolds number, aspect ratio, and the temperature of cylinder based on the power law model with a high goodness of curve fitting.