Water Tunnel Experiments on the Flow-Induced Vibration Characteristics of an Elastically Supported Bluff Body Near a Wall

2021 ◽  
Vol 2021.58 (0) ◽  
pp. F031
Author(s):  
Keita KAWAKAMI ◽  
Takahiro KIWATA ◽  
Takaaki KONO ◽  
Nobuyoshi KOMATSU
Keyword(s):  
Bluff Body ◽  
Vibration Characteristics ◽  
Water Tunnel ◽  
Flow Induced Vibration ◽  
Elastically Supported

Numerical Simulation of Flow-Induced Vibration of a Rectangular Cylinder

2003 ◽  
Author(s):  
Atsushi Enya ◽  
Atsushi Okajima
Keyword(s):  
Bluff Body ◽  
Cross Flow ◽  
Uniform Flow ◽  
Low Velocity ◽  
Flow Induced Vibration ◽  
Eddy Simulation ◽  
Rectangular Cylinder ◽  
Flow Induced Vibrations ◽  
High Reynolds ◽  
Elastically Supported

It is important for industrial purposes to predict flow-induced vibration of a bluff body elastically supported in an uniform flow. In this paper, the free oscillation of a rectangular cylinder with two-degree of freedom in the streamwise (in-line) and cross-flow (transverse) directions in a uniform flow, was computed by the Large Eddy Simulation (LES) method at high Reynolds number of 2.2 × 104. The Smagorinsky model was used as a subgrid scale (SGS) model. The main objectives of this work were to predict and estimate characteristics of flows around a free-oscillating cylinder. The present computations successfully reproduce various types of flow-induced vibrations of a free-oscillating rectangular cylinder as found by experiments; in-line oscillation, eddy-excitation and low-velocity galloping.

Spring-Arrangement Effect on Flow-Induced Vibration of a Circular Cylinder

2021 ◽  
Author(s):  
Koki Yamada ◽  
Yuga Shigeyoshi ◽  
Shuangjing Chen ◽  
Yoshiki Nishi
Keyword(s):  
Circular Cylinder ◽  
Dynamic Model ◽  
Geometric Nonlinearity ◽  
Water Channel ◽  
Fluid Flows ◽  
Flow Induced Vibration ◽  
Theoretical Evaluation ◽  
Circulating Water ◽  
Linear Dynamic ◽  
Elastically Supported

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.

Study on Flow-Induced Vibration Characteristics of Hydraulic Hoist of Large-Span Upwelling Radial Steel Gate

2011 ◽  
Vol 117-119 ◽  
pp. 241-246
Author(s):  
Zhen Hai Gao ◽  
Gen Hua Yan ◽  
Peng Liu ◽  
Fa Zhan Chen ◽  
Fei Ming Lv
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Characteristics ◽  
Vibration Response ◽  
Flow Induced Vibration ◽  
Structural Dynamic ◽  
Large Span ◽  
Response Characteristics ◽  
Lever Action ◽  
Structural Dynamic Characteristics ◽  
Steel Gate

In this paper we conduct study on flow-induced vibration of large-span upwelling radial steel Gate and its hydraulic hoist. Place an emphasis on vibration response characteristics under two working conditions of diversion and drainage, which proves the safety of hydraulic hoist gate vibration caused by gate vibration. Firstly, we study on dynamic characteristics of fluid-structure interaction of association system of gate and start and stop lever, reveals the discipline of the effect fluid having on structural dynamic characteristics. On this basis, flow-induced vibration characteristics under two conditions of with and without start and stop lever action considered. The results indicate that the gate vibration response with hydraulic hoist used decreases, which explains start and stop lever has certain effect of restraining vibration on gate vibration. In addition, under the working condition of drainage the vibration magnitude of start and stop lever is smaller than that of gate body, which explains there is damping action during transference of gate vibration through start and stop lever. The results find out that on the assumption of optimized gate structure and hydraulic arrangement, it is practicable, safe and reliable to adopt hydraulic hoist. The achievement has directive significance on similar projects construction in the future

Experimental Study on Flow-Induced Vibration of Floating Squared Section Cylinders With Low Aspect Ratio: Part I — Effects of Incidence Angle

2015 ◽  
Author(s):  
Rodolfo T. Gonçalves ◽  
Dênnis M. Gambarine ◽  
Felipe P. Figueiredo ◽  
Fábio V. Amorim ◽  
André L. C. Fujarra
Keyword(s):  
Aspect Ratio ◽  
Incidence Angle ◽  
Ocean Basin ◽  
Circular Cylinders ◽  
Structural Damping ◽  
Flow Induced Vibration ◽  
Double Frequency ◽  
Low Aspect Ratio ◽  
Aspect Ratios ◽  
Elastically Supported

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.

Experimental Study on Flow-Induced Vibration of Floating Squared Section Cylinders With Low Aspect Ratio: Part II — Effects of Rounded Edges

2016 ◽  
Author(s):  
Rodolfo T. Gonçalves ◽  
Dennis M. Gambarine ◽  
Aline M. Momenti ◽  
Felipe P. Figueiredo ◽  
André L. C. Fujarra
Keyword(s):  
Aspect Ratio ◽  
Reynolds Numbers ◽  
Ocean Basin ◽  
Separation Point ◽  
Flow Induced Vibration ◽  
Low Aspect Ratio ◽  
Aspect Ratios ◽  
Significant Difference ◽  
Flow Induced Vibrations ◽  
Elastically Supported

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.

206 Flow-induced Vibration of an Elastically Supported Cylinder Having Nonlinearity

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