Flow-induced vibration of elastically supported rectangular cylinders

2003 ◽  
Author(s):  
Jeffrey L. Garrett
Author(s):  
Koki Yamada ◽  
Yuga Shigeyoshi ◽  
Shuangjing Chen ◽  
Yoshiki Nishi

Abstract Purpose This study elucidated the effect of an inclined spring arrangement on the flow-induced vibration of a circular cylinder to understand if the effect enhances the harnessing of the energy of fluid flows. Method An experiment was conducted on a circulating water channel. A circular cylinder was partially submerged. It was elastically supported by two springs whose longitudinal directions were varied. With the speed of the water flow varied, the vibrations of the circular cylinder were measured. The measured vibrations were interpreted by la linear dynamic model. Results and discussion In a few cases, a jump in response amplitudes from zero to the maximum was observed with the spring inclination at reduced velocities of 6 to 7, whereas gradually increasing response amplitudes were observed in other cases. The inclined spring arrangement achieved greater velocity amplitudes than in cases without spring inclination. A theoretical evaluation of the measured responses indicates that the effect of the inclined springs was caused by geometric nonlinearity; the effect would be more prominent by employing a longer moment lever.


Author(s):  
Rodolfo T. Gonçalves ◽  
Dênnis M. Gambarine ◽  
Felipe P. Figueiredo ◽  
Fábio V. Amorim ◽  
André L. C. Fujarra

Experiments regarding flow-induced vibration on floating squared section cylinders with low aspect ratio were carried out in an ocean basin with rotating-arm apparatus. The floating squared section cylinders were elastically supported by a set of linear springs to provide low structural damping to the system. Three different aspect ratios were tested, namely L/D = 1.0, 2.0 and 3.0, and two different incidence angles, namely 0 and 45 degrees. The aims were to understanding the flow-induced vibration around single columns of multi-column platforms, such as semi-submersible and TLP. VIV on circular cylinders were also carried out to compare the results. The range of Reynolds number covered was 2,000 < Re < 27,000. The in-line and transverse amplitude results showed to be higher for 45-degree incidence compared with 0-degree, but the maximum amplitudes for squared section cylinders were lower compared with the circular ones. The double frequency in the in-line motion was not verified as in circular cylinders. The yaw amplitudes cannot be neglected for squared section cylinders, maximum yaw amplitudes around 10 degrees were observed for reduced velocities up to 15.


Author(s):  
Rodolfo T. Gonçalves ◽  
Dennis M. Gambarine ◽  
Aline M. Momenti ◽  
Felipe P. Figueiredo ◽  
André L. C. Fujarra

Experiments regarding flow-induced vibration on floating rounded squared section cylinders with low aspect ratio were carried out in an ocean basin equipped with a rotating-arm apparatus. Floating squared section cylinders with rounded edges and aspect ratios of L/D = 2.0 were elastically supported by a set of linear springs in order to provide low structural damping to the system. Two different incidence angles were tested, namely 0 and 45 degrees. The Reynolds numbers covered the range from 2,000 to 30,000. The aim was to understand the flow-induced vibrations around single columns, gathering information for further understanding the causes for the Vortex-Induced Motions in semi-submersible and TLP platforms. Experiments on circular and squared sections cylinders (without rounded edges) were also carried out to compare the results with the rounded square section cylinders (with rounded edges). The amplitude results for in-line, transverse and yaw amplitude for 0-degree models showed to be higher for squared section cylinders compared to those for the rounded square section cylinders. No significant difference between the 45-degree models was observed. The results of ratio between frequency of motion in the transverse direction and natural frequency in still water confirmed the vortex-induced vibration behavior for the squared and rounded square section cylinders for 45-degree incidence; and also the galloping characteristics for 0-degree incidence cases. The rounded effect on the square section cylinders showed to be important only for reduced velocity larger than 8, which is probably related to the position of the separation point that changes around the rounded edge, behavior that did not occurr for the squared edge that fixed the separation point for any reduced velocity.


2009 ◽  
Vol 2009 (0) ◽  
pp. _206-1_-_206-6_
Author(s):  
Yukinori Kobayashi ◽  
Yuhei Takeshita ◽  
Subekti ◽  
Yohei Hoshino ◽  
Takanori Emaru

2021 ◽  
Vol 1203 (2) ◽  
pp. 022025
Author(s):  
Irena Gołębiowska ◽  
Maciej Dutkiewicz ◽  
Tomasz Lamparski ◽  
Poorya Hajyalikhani

Abstract Slender cylindrical structures such as overhead transmission lines, skyscrapers, chimneys, risers, and pipelines can experience flow induced vibration (FIV). The vortex vibrations are a type of FIV; they arise because of oscillating forces caused by flow separation and the detachment of vortices. The paper presents a brief overview of experimental research on vortex induced vibration - VIV of short, rigid cylinders elastically supported (with a small aspect ratio). This overview summarizes the basic results of the vortex vibration (VIV) which have been performed in the last five decades. These studies were mainly related to determining the influence of selected parameters - mass, damping and Reynolds number on the cylinder response, either in one direction only or simultaneously in the flow direction and transverse to the flow direction, and with the search for a map of vortex images in the trace (vortex wake pattern map).


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