Shape Effects of Octagonal Cross Sections on Vortex-induced Vibration Characteristics

Abstract

This study focuses on motion-induced vortex vibration occurring from Vcr=0.83B/D. This is an experimental study of the effect of the change in cross-sectional shape on the vortex-induced vibration response characteristics when the chamfer angle is gradually changed. As a result, when the angle is less than 5 deg., separated vortex from leading edge are generated on the upper and lower surfaces of the cross section and motion-induced vortex vibration occurs, but when the angle is 10, 15 deg., the generation of separated vortex from leading edge weakens, and instead Kármán vortex generated from the trailing edge gradually strengthened. Therefore, the vibration is likely to change to Kármán-vortex vibration from motion-induced vortex vibration as the chamfer angle θ is increasing.