TY - JOUR
T1 - Two degree of freedom flow-induced vibration of cylindrical structures in marine environments: frequency ratio effects
AU - Han, Xiangxi
AU - Lin, Wei
AU - Zhang, Xiaojun
AU - Tang, Youhong
AU - Zhao, Chengbi
PY - 2016/9/1
Y1 - 2016/9/1
N2 - The flow-induced vibration of a cylindrical structure is a very common problem in marine environments such as undersea pipelines, offshore risers, and cables. In this study, the vortex-induced vibration (VIV) of an elastically mounted cylinder at a low Reynolds number is simulated by a transient coupled fluid–structure interaction numerical model. Considering VIV with low damping ratio, the response, hydrodynamic forces, and vortex shedding modes of the cylinder is systematically analyzed and summed up the universal rule under different frequency ratios. On the basis of the analysis, we find that the frequency ratio α is a very important parameter. It decides the locked-in, beat, and phase-switch phenomena of the cylinder, meanwhile, it also influence the vortex mode of the cylinder. The trajectory of the two degrees of freedom (2 DOF) case at different natural frequency ratios is discussed, with most trajectories having a “figure of 8” shape and a few having a “crescent” shape. A fast Fourier transformation technique is used to obtain the frequency characteristics of the vibration of the cylindrical structure. Using the 2 DOF cylinder model in place of the 1 DOF model presents several advantages in simulating the nonlinear characteristics of cylindrical structures, including the capacity to model the crosswise vibration generated by in-line vibration.
AB - The flow-induced vibration of a cylindrical structure is a very common problem in marine environments such as undersea pipelines, offshore risers, and cables. In this study, the vortex-induced vibration (VIV) of an elastically mounted cylinder at a low Reynolds number is simulated by a transient coupled fluid–structure interaction numerical model. Considering VIV with low damping ratio, the response, hydrodynamic forces, and vortex shedding modes of the cylinder is systematically analyzed and summed up the universal rule under different frequency ratios. On the basis of the analysis, we find that the frequency ratio α is a very important parameter. It decides the locked-in, beat, and phase-switch phenomena of the cylinder, meanwhile, it also influence the vortex mode of the cylinder. The trajectory of the two degrees of freedom (2 DOF) case at different natural frequency ratios is discussed, with most trajectories having a “figure of 8” shape and a few having a “crescent” shape. A fast Fourier transformation technique is used to obtain the frequency characteristics of the vibration of the cylindrical structure. Using the 2 DOF cylinder model in place of the 1 DOF model presents several advantages in simulating the nonlinear characteristics of cylindrical structures, including the capacity to model the crosswise vibration generated by in-line vibration.
KW - Fluid–structure interaction
KW - System coupling
KW - Vortex-induced vibration
UR - http://link.springer.com/article/10.1007/s00773-016-0370-5
UR - http://www.scopus.com/inward/record.url?scp=84959079610&partnerID=8YFLogxK
U2 - 10.1007/s00773-016-0370-5
DO - 10.1007/s00773-016-0370-5
M3 - Article
SN - 0948-4280
VL - 21
SP - 479
EP - 492
JO - JOURNAL OF MARINE SCIENCE AND TECHNOLOGY
JF - JOURNAL OF MARINE SCIENCE AND TECHNOLOGY
IS - 3
ER -