Shear flow induced vibrations of long slender cylinders with a wake oscillator model

• Published in: Acta mechanica Sinica Vol. 27; no. 3; pp. 330 - 338
• Main Authors: Ge, Fei, Lu, Wei, Wang, Lei, Hong, You-Shi
• Format: Journal Article
• Language: English
• Published: Heidelberg The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences 01.06.2011
• Subjects: Classical and Continuum Physics; Computational fluid dynamics; Computational Intelligence; Cylinders; Engineering; Engineering Fluid Dynamics; Fluid flow; Mathematical models; Oscillators; Research Paper; Shear flow; Theoretical and Applied Mechanics; Vibration; Wakes; 剪切流动; 子模; 尾流; 旋涡脱落频率; 时域模型; 涡激振动; 非均匀流; 非线性流体; Vortex-induced wave; Long slender cylinder; Wake oscillator; Shear flow; Vortex-induced vibration
• ISSN: 0567-7718; 1614-3116; 1614-3116
• DOI: 10.1007/s10409-011-0460-x

A time domain model is presented to study the vibrations of long slender cylinders placed in shear flow. Long slender cylinders such as risers and tension legs are widely used in the field of ocean engineering. They are subjected to vortex-induced vibrations（VIV） when placed within a transverse incident flow. A three dimensional model coupled with wake oscillators is formulated to describe the response of the slender cylinder in cross-flow and in-line directions. The wake oscillators are distributed along the cylinder and the vortex-shedding frequency is derived from the local current velocity. A non-linear fiuid force model is accounted for the coupled effect between cross-flow and in-line vibrations. The comparisons with the published experimental data show that the dynamic features of VIV of long slender cylinder placed in shear flow can be obtained by the proposed model,such as the spanwise average displacement,vibration frequency,dominant mode and the combination of standing and traveling waves. The simulation in a uniform flow is also conducted and the result is compared with the case of nonuniform flow. It is concluded that the flow shear characteristic has significantly changed the cylinder vibration behavior.