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

作　　者：Fei Ge Wei Lu Lei Wang You-Shi Hong 

机构地区：[1]State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, CAS, 100190 Beijing, China

出　　处：《Acta Mechanica Sinica》2011年第3期330-338,共9页力学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (10532070);the Knowledge Innovation Program of Chinese Academy of Sciences (KJCX2-YW-L07);the LNM Initial Funding for Young Investigators

摘　　要：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.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.

关 键 词：Vortex-induced vibration Vortex-induced wave Shear flow Wake oscillator Long slender cylinder 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] O357.52[交通运输工程—道路与铁道工程]