Affiliations: School of Energy and Power Engineering,
Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, P.
R. China. E-mail: fhwang@mail.xjtu.edu.cn | School of Mechanical Engineering, Xi'an
Jiaotong University, Xi'an, Shaanxi, 710049, P. R. China | Department of Mechanical Engineering, The Hong Kong
Polytechnic University, Hung Hom, Kowloon, Hong Kong
Abstract: The near wake of a varicose cylinder has been experimentally
investigated using Laser Induced Fluorescence (LIF) and Digital Particle
Imaging Velocimetry (DPIV). The work aims to provide understanding to the
mechanism of the cross flow around varicose cylinder as well as to comprehend
why the introduction of relatively small degrees of spanwise waviness can have
a significant effect on drag reduction and suppression of the cylinder
vibration. The evolution of the flow patterns and the corresponding vortex
interactions are obtained. The experimental results indicated that the wake
width and the formation length vary along the span of the varicose cylinder. A
wider wake and a longer formation length were observed in the saddle plane. In
addition, an interpretation of the three-dimensional wake structures is
postulated and conceptually shown. The numerical simulation by 3-D finite
volume method is successful in predicting the flow features found by the
experiments.
