Large eddy simulation of flow and heat transfer past two side-by-side spheres

The present study numerically investigated the flow and heat transfer past two side-by-side spheres using the large eddy simulation (LES) method at Re = 5000. The gap ratios (G/D) between the two side-by-side spheres ranged from 1.25 to 3.0. The predicted flow characteristics around the spheres agree well with literature data. The mean Nusselt number and local Nusselt number variation were also captured. The results show that, as the gap ratio, G/D, decreases, the average drag coefficients, C_D, for both spheres increase, but the mean Nusselt numbers do not change much. However, the local Nusselt number variation on the surfaces varies greatly as the gap ratio changes. The nozzle effect for the flow between the spheres is enhanced and the cross-stream mixing becomes stronger as the gap ratio decreases. A biased gap flow which occurs when G/D = 1.25 influences the wake zone length and the drag coefficients on the spheres.