Numerical evaluation of passive control of VIV by small control rods

Zhu, Hongjun; Yao, Jie

doi:10.1016/j.apor.2015.03.003

Cited by 108 publications

(32 citation statements)

References 51 publications

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“…Since the fluid flow is incompressible, unsteady and viscous, the governing equations in the entire domain are two-dimensionally unsteady Reynolds averaged Navier-Stokes (RANS) equations, including mass conservation equation and momentum conservation equation, as follows [5,13,19,23]:…”

Section: Numerical Approachmentioning

confidence: 99%

“…The RANS equations are commonly solved with the assistance of two-equation turbulence models in solving practical problems. Since the direct numerical simulation (DNS) will spend a lot of time solving the RANS equations [13]. The SST K-ω (a two-equation turbulence model) turbulence model shows a great performance in simulating the flow around the structure [1,5,13,19,23].…”

Section: Numerical Approachmentioning

confidence: 99%

“…Since the direct numerical simulation (DNS) will spend a lot of time solving the RANS equations [13]. The SST K-ω (a two-equation turbulence model) turbulence model shows a great performance in simulating the flow around the structure [1,5,13,19,23]. Therefore, SST k-ω turbulence model is adopted to close the RANS equations, which has the kinetic energy (k t ) and the specific dissipation rate (ω), expressed as [5,13,19,23,24]:…”

Section: Numerical Approachmentioning

confidence: 99%

“…Gao et al [12] numerically investigated the effect of different surface roughness on VIV suppression, and results showed that the amplitude response decreased and drag coefficient decreased as the roughness increases. Zhu and Yao [13] presented a method of VIV suppression using small control rods, and results showed that the suppression effect was the best when the number of control rods was 9. The suppression effect of traveling wave wall (TWW) on VIV was studied numerically by Xu et al [14], and a small vortex shedding was observed.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numerical Investigation on Vortex-Induced Vibration Suppression of a Circular Cylinder with Axial-Slats

Wang

Mao

Tian

et al. 2019

JMSE

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The vortex-induced vibration (VIV) suppression of a circular cylinder with the axial-slats is numerically investigated using the computational fluid dynamics (CFD) method for Reynolds number range of 8.0 × 10 3 -5.6 × 10 4 . The two-dimensional unsteady Reynolds averaged Navier-Stokes (RANS) equations and Shear-Stress-Transport (SST) turbulence model are used to calculate the flow around the cylinder in ANSYS Fluent. The Newmark-β method is used to evaluate structural dynamics. The amplitude response, frequency response and vortex pattern are discussed. The suppression effect of the axial-slats is the best when the gap ratio is 0.10 and the coverage ratio is 30%. Based on the VIV response, the whole VIV response region is divided into four regions (Region I, Region II, Region III and Region IV). The frequency ratio of isolated cylinder jumps between region II and region III. However, the frequency ratio jumps between region I and region II for a cylinder with the axial-slats. The axial-slats destroy the original vortex and make the vortex easier to separate. The online amplitude ratio is almost completely suppressed, and the cross-flow amplitude ratio is significantly suppressed. effect of different surface roughness on VIV suppression, and results showed that the amplitude response decreased and drag coefficient decreased as the roughness increases. Zhu and Yao [13] presented a method of VIV suppression using small control rods, and results showed that the suppression effect was the best when the number of control rods was 9. The suppression effect of traveling wave wall (TWW) on VIV was studied numerically by Xu et al. [14], and a small vortex shedding was observed. A circular cylinder attached with helical strakes on VIV suppression was numerically investigated [15], and it could be found that helical strake could change vibration frequency and suppress the vortex shedding. Huera-Huarte [16] investigated the suppression effect of wire meshes on VIV, and the maximum amplitude response could be reduced by 95%. Lou et al. [17] experimentally investigated the suppression effect of splitter plates, and it was found that the length ratio of splitter plate was an important factor on VIV suppression. Zheng and Wang [18] investigated the suppression effect of different shaped fairing devices on VIV. There are many researches on axial-rods [19][20][21], but there are few researches on axial-slats.In this study, the VIV response of a circular cylinder with the axial-slats is numerically investigated using the computational fluid dynamics (CFD) method for Reynolds number range of 8.0 × 10 3 < Re < 5.6 × 10 4 . The two-dimensional unsteady Reynolds averaged Navier-Stokes (RANS) equations in conjunction with the SST k-ω turbulence model are used to calculate the flow around the cylinder. The Newmark-β method is used to evaluate the structural dynamics. The physical model is established in Section 2, and the numerical model is established in Section 3. In Section 3, the numerical model is verified by experimental results. T...

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Section: Numerical Approachmentioning

confidence: 99%

Section: Numerical Approachmentioning

confidence: 99%

Section: Numerical Approachmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Numerical Investigation on Vortex-Induced Vibration Suppression of a Circular Cylinder with Axial-Slats

Wang

Mao

Tian

et al. 2019

JMSE

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“…Lam [9] discussed the flow around a corrugated cylinder by large eddy simulation and experiment, and they controlled the vibration of the tube bundle in a heat exchanger by adding a corrugated cylinder to the tube bundle array. Zhu [10] and Song [11] studied the inhibition effect of small control rods on vortex-induced vibration (VIV). The former compared the VIV characteristics under different rod numbers, diameter ratios and gap ratios.…”

mentioning

confidence: 99%

Effect of Gap Flow on the Characteristics of Flow-Around and Flow-Induced Vibration for Two Circular Cylinders with Roughness Strips

Yang

Ding

et al. 2019

Applied Sciences

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In order to understand the gap flow between two cylinders, the characteristics of flow around two stationary cylinders and the flow-induced vibration of two staggered cylinders with roughness strips are numerically studied. The lift-drag responses, Strouhal number (St) and wake structure of two stationary cylinders in tandem, as well as the vibration response and vortex pattern of two oscillating staggered cylinders are analyzed. The results indicate that the spacing d c of two stationary cylinders at which the gap flow can be observed is different for different Re, and d c is 3D when Re = 2000 and d c = 2.5D at Re = 6000~14,000. When the distance d = d c , the force coefficient and St of two cylinders increase sharply. For the two oscillating staggered cylinders, there is a critical reduced velocity U c * = 7, which makes the amplitude magnitude relationship of the two cylinders change. With the change of the reduced velocity, the vibration frequencies of the two cylinders are consistent. When the staggered distance increases, the frequency difference of the two cylinders decreases. At the same inflow velocity, with the increase of staggered distance, a gap flow is formed between the two cylinders. When T > 0.6D and U* < 8, the gap flow becomes the main factor affecting the vibration of the two cylinders, which can be divided into the dominant region of gap flow.The FIV of a bluff body is a very complicated fluid-solid coupling process. Many studies have been done in this field, mainly focusing on the FIV characteristics and vibration control of the bluff body. The representative reviews of FIV of cylinders are by Williamson [5] and Bearman [6]. The control of FIV is embodied in two aspects. On the one hand, it is the suppression of vibration. Canpolat [7] found that rectangular grooves on a cylinder can effectively control flow through PIV experiments. Feng [8] used a water tunnel experimentation study and found that a synthetic jet can significantly change the scale of eddy current and wake mode. Lam [9] discussed the flow around a corrugated cylinder by large eddy simulation and experiment, and they controlled the vibration of the tube bundle in a heat exchanger by adding a corrugated cylinder to the tube bundle array. Zhu [10] and Song [11] studied the inhibition effect of small control rods on vortex-induced vibration (VIV). The former compared the VIV characteristics under different rod numbers, diameter ratios and gap ratios. It was found that when the attachment had nine control rods, the diameter ratio was 0.15, and the clearance ratio was 0.6, the inhibition effect of VIV was the best. The latter simulated the VIV characteristics of a cylinder with three small control rods at different angles of attack and clearance ratios. It was found that the inhibition effect was the best when the angle of attack was 45 and the clearance ratio was 0.9. Wu et al. [12] found a new method to control VIV: A twisted cylinder, which was applied to a semi-submersible offshore platform. Compared with a square cylinder, the...

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An experimental study of a two‐degree‐of‐freedom galloping energy harvester

Wang

Huang

et al. 2020

Int J Energy Res

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Summary The cut‐in wind speed and the power output are the two main concerns of a galloping energy harvester. A good galloping energy harvester is expected to have a low cut‐in wind speed and a high power output. This paper proposes a two‐degree‐of‐freedom (2‐DOF) galloping‐based piezoelectric energy harvester (GPEH) by mounting a secondary beam onto a primary piezoelectric cantilever beam. An experimental study is conducted to evaluate the actual energy harvesting performance of the proposed 2‐DOF GPEH. The effects of the secondary beam length and the mounting position on the cut‐in wind speed and the power output are investigated. It is revealed that the introduction of the secondary beam can reduce the cut‐in wind speed from 2.372 m/s to 1.961 m/s. Mounting the secondary beam further away from the bluff body weakens the influence of the secondary beam on the energy harvesting performance of the 2‐DOF GPEH. Moreover, the power output can be increased or decreased by tuning the secondary beam length. The power output from a well‐tuned 2‐DOF GPEH can be increased for about 111.1%, as compared to the conventional 1‐DOF GPEH. By contrast, the power output from a badly tuned 2‐DOF GPEH is reduced for about 22.2%. A simple theoretical model is developed for explaining the experimentally observed phenomenon and can be used to provide some guidelines in the design of 2‐DOF GPEH to avoid performance deterioration.

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Numerical evaluation of passive control of VIV by small control rods

Cited by 108 publications

References 51 publications

Numerical Investigation on Vortex-Induced Vibration Suppression of a Circular Cylinder with Axial-Slats

Numerical Investigation on Vortex-Induced Vibration Suppression of a Circular Cylinder with Axial-Slats

Effect of Gap Flow on the Characteristics of Flow-Around and Flow-Induced Vibration for Two Circular Cylinders with Roughness Strips

An experimental study of a two‐degree‐of‐freedom galloping energy harvester

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