Hydrodynamic characteristics of two tandem flexible cylinders undergoing flow-induced vibration

Ma, Yanfei; Xu, Wanhai; Zhai, Libin; Ai, H. X.

doi:10.1016/j.oceaneng.2019.106587

Cited by 29 publications

(3 citation statements)

References 44 publications

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“…The in-line rotational motion (pitch motion) frequencies of the UMP are about 2 times than the transverse rotational motion (roll motion) frequencies [32,33]. And the in-line rotational motion (pitch motion) amplitudes are much less than the transverse rotational motion (roll motion) amplitudes [30,34]. Therefore, in this study, the in-line rotational (pitch motion) and transverse rotational (roll motion) VIV motions of the UMP are defined as base excitations exerting on the inertial pendulum energy The amplitude of the roll motion is fixed as G =  6 referred to Zhang's experimental results [31].…”

Section: Dynamic Analysis Of the Umpmentioning

confidence: 96%

Performance evaluation of a two-directional energy harvester with low-frequency vibration

Ding

Mao

Cao

et al. 2020

Smart Mater. Struct.

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This study evaluates the power harnessing performance of a two-directional inertial pendulum energy harvester for miniature underwater mooring platforms (UMPs). This novel harvester can achieve a dominant rotational motion under different parametrical excitations. The two-directional energy harvesting performance is investigated through vibration platform experiments over rollpitch coupling excitations. The frequency ratio between the pitch and roll motion is about 2 to 1, the roll excitation frequency is over the range of 0.2-0.3 Hz, and the pitch amplitude is much lower than the roll amplitude. Experimental results indicate that the inclination configuration of the harvester can improve two-directional energy harvesting performance significantly with lowfrequency vibration. Geometrical tunability through adjusting inclination configuration for the harvester can enhance the two-directional energy harvesting apparently. Four prominent phenomena of the two-directional energy harvesting performance are observed with the increasing load resistance. The motion state transformation of the inertial pendulum can result in dramatical jumps or drops in two-directional energy harvesting.

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Section: Dynamic Analysis Of the Umpmentioning

confidence: 96%

Performance evaluation of a two-directional energy harvester with low-frequency vibration

Ding

Mao

Cao

et al. 2020

Smart Mater. Struct.

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“…In this method, other bodies are positioned downstream of the oscillating cylinder, e.g. splitter plates (Assi et al, [2]; Ali et al, [3]; Maruai et al, [4]; Dash et al, [5]), a circular cylinder (Shirakashi et al, [6]; Bae et al, [7]; Ngyuen et al, [8]; Ma et al, [9]; Chauhan et al, [10]) or a strip plate in cruciform arrangement (Koide et al, [11]; Kato et al, [12]; Kawabata et al, [13]) and fairings (Assi et al, [14]; Yu et al, [15]; Wang et al, [16]; Lou et al, [17]; Zheng and Wang [18]).…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Effect of a Downstream Square Plate on Vortex-induced Vibration and Galloping of a Square Cylinder

Mohamed¹,

Zaki²,

Shirakashi³

et al. 2020

ARFMTS

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A square cylinder exposed to a fluid flow is regarded as the simplest model of the structures in sea water or air flow, and known to show the Karman vortex induced vibration (KVIV) and the galloping in separate or overlapping ranges of flow velocity. In this study, wind tunnel experiments were performed on the cross-flow vibration of a square cylinder, and effects of a downstream square plate on the vibration were investigated to develop a convenient passive technique for vibration control. The square plate has a side length w equal to the side length of the square cylinder D (= 26 mm) and set downstream with the gap ratio S/D in the range of 0.12 to 2.90 where S is the separation gap. The results show that the square plate has only little influence on KVIV and enhances the galloping, resulting in the lower critical reduced velocity of galloping Ug i.e. the onset velocity of galloping reduced to about half of the isolated counterpart at S/D = 0.98. Most remarkable effect of the downstream square plate is the enhancement of the vibration near the peak velocity of KVIV at S/D = 1.17, which is around five times larger as compared with the isolated counterpart. This may indicate occurrence of the wake-body-interference fluid elastic vibration.

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“…In isothermal incompressible flow, many well-documented numerical investigations [15][16][17][18][19][20][21][22][23] had been published to assess the complicated coupling of fluid and structural dynamics. Furthermore, in multibody systems, e.g., side-by-side, [24][25][26][27][28] tandem, [29][30][31] near-wall, [32][33][34] or array 35,36,62 configurations, the interference could be extremely complex and subtly associated with hydrodynamic instabilities. In this study, the primary focus is to study the effect of cross thermal buoyancy and heat convection on the hydrodynamic and structural stability, which are the key aspects in many engineering applications.…”

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confidence: 99%

Secondary lock-in of vortex-induced vibration and energy transfer characteristics of a vibrating cylinder subject to cross buoyancy

Liu

Zhu

2021

Physics of Fluids

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The hydrodynamic and thermal characteristics of a freely vibrating circular cylinder subject to cross buoyancy are numerically investigated at low Reynolds numbers. The structural responses and onset of vortex-induced vibration (VIV) are documented over a range of parameter space, 2:0 reduced velocity (Ur) 10:0; 0:7 Prandtl number (Pr) 10:0 and 0:5 Richardson number (Ri) 2:0. The fluid and structural coefficients are chosen as Reynolds number ðReÞ ¼ 100, mass ratio ðm Ã Þ ¼ 10:0, and damping ratio ðfÞ ¼ 0:01. A phenomenon of secondary VIV lockin is found in the cases of Ri ¼ 2.0 (the cross buoyancy effect becomes influential), Pr . 2:0 and Ur Z 7:0. An extended VIV lock-in region is formed over a wide range of reduced velocity values together with a tremendous kinetic energy transfer between fluid and structure. This finding is significant for the research of hydropower harvesting. On the other hand, the influence of structural dynamics on heat convection over the surface of a heated circular cylinder is recorded and discussed as well. The significance and mutual influence between Prandtl and Richardson numbers on hydrodynamics, structural dynamics, and heat convection are discussed in detail. The temperature contours are found concentrating around the cylinder's surface in the cases of high Prandtl numbers, which are also associated with higher mean Nusselt number (Nu) values. The influence on heat convection over a cylinder's surface is quantified via the computation of Nu and its fluctuation for different circumstances. The energy transfer coefficient is employed to quantify the kinetic energy transfer between the fluid and a heated structure in mixed convective flow. The phase angle difference between the transverse displacement and lift force is used to support the discussions of energy transfer in fluid.

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Hydrodynamic characteristics of two tandem flexible cylinders undergoing flow-induced vibration

Cited by 29 publications

References 44 publications

Performance evaluation of a two-directional energy harvester with low-frequency vibration

Performance evaluation of a two-directional energy harvester with low-frequency vibration

Experimental Investigation of the Effect of a Downstream Square Plate on Vortex-induced Vibration and Galloping of a Square Cylinder

Secondary lock-in of vortex-induced vibration and energy transfer characteristics of a vibrating cylinder subject to cross buoyancy

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