The Effect of Transverse Curvature on the Drag and Vortex Shedding of Elongated Bluff Bodies at Low Reynolds Number

Abstract

This paper establishes the drag characteristics of finite cylinders of aspect ratio 1, 4, 10 and 100 for Reynolds numbers less than 1000 including the viscous regime. The effect of the drag and vortex shedding characteristics of curving a finite cylinder into a toroidal shape is investigated. The curvature reduces drag by as much as 13 percent over its linear counterpart in the viscous regime. Vortex shedding characteristics of tori include all the features of cylinders in addition to a solidity range that behaves like solid bodies and an intermediate range where two vortex flow patterns can exist. These patterns can occur either as alternating ring vortices or a less common but more stable counterrotating helical vortex pair.