Fluid flow and heat transfer characteristics past two tandem elliptic cylinders: A numerical study

In this paper, fluid flow and heat transfer characteristics are analyzed numerically for fluid flow past two elliptic cylinders arranged in a tandem manner. The numerical computation was performed using an in-house code based on the SUPG - FEM algorithm. Isothermal boundary condition is imposed on the surface of both the elliptic cylinders. Parametric studies are carried out by varying the axis ratio of the elliptic cylinders (AR = 0.5, 0.8, and 1.0) and distance between the two cylinders (L/D = 1.5, 2.0, 2.5, 3.5, and 5.0) for different Reynolds numbers (Re = 50, 100, 150, and 200). Parameters such as pressure coefficient, drag coefficient, lift coefficient, Strouhal number, and Nusselt number are calculated for all the cases. It is observed that the critical spacing ratio (distance between the cylinders at which the mean drag coefficient shows a sharp increase) of the cylinders shifts toward a lower value at Re = 200 for AR = 0.5 and 0.8. It is also found that for both the cylinders, convective heat transfer increases for elliptic cylinders with lower axis ratio (AR = 0.5 and 0.8). Finally, correlations are derived for mean drag coefficient and average Nusselt number as a function of Reynolds number, spacing ratio, and axis ratio.