Reynolds number effect on the fluid flow and heat transfer around a harbor seal vibrissa shaped cylinder

This study numerically investigates the effect of the Reynolds number (Re) on the characteristics of the fluid flow and heat transfer from a biomimetic elliptical cylinder inspired by a harbor-seal vibrissa (HSV). We considered the Re range of 50-500 and Prandtl number (Pr) of 0.7. Circular and elliptical cylinders with the same hydraulic diameter were compared. The results confirm the effectiveness of the unique geometry of the HSV in the low Reynolds number regime for reduction drag and the suppression of lift fluctuation. The root-mean-square (RMS) value of the lift fluctuation is almost negligible for the unsteady regime of the HSV in this range of Re. The time histories of the force coefficients and flow structures revealed the onset of the unsteady flow for the HSV within the present range of Re. The spanwise dependency of the local surface-averaged Nusselt number becomes stronger as Re increases. In the unsteady flow regime, a periodic thermal plume appears at the nodes of the HSV, which was induced by the non-reverse flow region that expanded the isotherms downstream.