An Experimental Investigation of Forces on a Textured Cylinder at Subcritical Reynolds Numbers

Spanwise deviations from a perfect circular cross-section, affect the aerodynamics and hydrodynamics of cylindrical structures. In this study the ability of a novel wavy cylinder, the textured cylinder, to reduce applied drag and lift forces is investigated experimentally. Three different configurations of the proposed textured geometry, as well as a bare cylinder and a cylinder with helical strakes are ۳D printed and tested in an open circuit wind tunnel. Tests are conducted at Reynolds numbers from ۳.۵×۱۰۴ to ۸.۰×۱۰۴. Results show that the time-averaged drag and fluctuating lift forces on the textured cylinder can be ۲۰% and ۱۵% lower than those of a bare cylinder, respectively. Amongst the tested cylinders, the straked cylinder exhibited the lowest fluctuating lift forces. However, the lowest time-averaged drag forces were measured on the textured cylinder, Tex۳۰, through the range of Reynolds numbers tested. The Strouhal number of the Tex۳۰ was found to be between those of the bare and straked cylinders.

Keywords:

Textured cylinder , Aerodynamic forces , Strouhal number , Wavy cylinder