Author(s)

Hirono Matsumoto¹, Yoshihiro Kubota², Masayuki Ohishi³, Osamu Mochizuki⁴

¹Graduate School of Biomedical Engineering, Toyo University, Saitama, Japan.
²Faculty of Science and Engineering, Toyo University, Saitama, Japan.
³Daikirika Kogyo Inc., Saitama, Japan.
⁴Department of Biomedical Engineering, Toyo University, Saitama, Japan.

The drag on a cylinder with an apple-shaped cross section was studied numerically in this paper. This cross section is adopted because the drag on an apple is known to be lower than that of a sphere. Since the hollows of an apple seem to be points of drag reduction, two-dimensional numerical simulations of cylinders with hollows of several shapes are carried out at a Reynolds number of 6.7 × 104 by using the vortex method to check their effects. The cylinder with hollows like those of a real apple attained a 13% reduction in drag compared with a circular cylinder. Other geometrical hollow-shapes, namely, V-shaped and U-shaped grooves, also reduced drag from the circular model, but these effects were less pronounced than those of the apple-shaped cross section. It was concluded that an apple-like hollows were effective for drag reduction of a cylin-der as well as a sphere.

Drag Reduction, Apple, Cylinder, Vortex Method, k-ε Model, Flow Visualization

Matsumoto, H. , Kubota, Y. , Ohishi, M. and Mochizuki, O. (2016) Drag on a Cylinder with an Apple-Shaped Cross Section. World Journal of Mechanics, 6, 323-339. doi: 10.4236/wjm.2016.69024.