Utilising flags to reduce drag around a short finite circular cylinder

ABSTRACT

This paper utilises flags to decrease the drag around a short finite circular cylinder. Wall-adapted large eddy simulation and two-way fluid–structure interaction methods were applied to resolve unsteady turbulent flow structure. The far-field Reynolds number of the current configuration based on the cylinder diameter was chosen to be 20,000. In addition, the length-to-diameter ratio of the cylinder was assumed to be L/D = 2 whereas the flexible flag had a width-to-diameter ratio of W/D = 1.5. The results were compared with the regular short finite circular cylinder and the rigid flagged cylinder in our previous work. The results indicate that utilising flags inside the near-wake region of the cylinder reduces the pressure drag. The physical mechanism of this drag reduction is presented.

KEYWORDS:

• Short finite circular cylinder
• rigid and flexible flag
• FSI and LES-WALE
• drag force
• wake region

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. 3D Streamlines for Figures 13–15 were plotted in the same condition.