Suppression of Flow-Induced Vibration of Three Tandem Cylinders by Helical Strakes Under Wake Induced Galloping DOI

Bowen Tang,

Xiantao Fan, Jiawei Wang

et al.

Published: Jan. 1, 2023

Flow-induced vibration (FIV) is an important phenomenon that frequently occurs in practical scenarios, such as chemical towers, chimneys, risers, and offshore structures. Employing effective methods to control FIV crucial for ensuring the safety long-term operation of engineering Due limitations current passive techniques adequately suppressing wake-induced galloping (WIG) tandem cylinders, seven different types helical strakes with varying heights G, pitches P, cross-sectional shapes (square “S”, involute “I”, D-shaped “D”) were designed. Experimental conducted a wind tunnel investigate dynamic responses cylinders (m*ξ=0.09) at spacings, resulting three modes. The amplitude, frequency, three-dimensional computational fluid dynamics (CFD) simulations performed analyze configurations strakes. It was discovered can effectively suppress multi-frequency instability bare cylinders. For speeds U < 6m/s, "S" strake achieved suppression efficiency up 665%. Moreover, larger pitch led less flow interference on spanwise height, significant effects. Furthermore, it observed has stronger influence boundary layer formation compared "D" strake. This results weaker shedding vortices separation point due absence negative pressure gradient shear layer, thus revealing mechanisms cross-sections cylinder dynamics.

Language: Английский

Experimental study of the flow-induced vibration of a cut-corner prism energy harvester DOI
Weizhe Wang, Zhaohui Yao

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(6)

Published: June 1, 2024

In this paper, an experimental study of the performance energy harvester was conducted to investigate effect length parallel side (PS) on cut-corner prism. The experiments were carried out in a recirculating wind tunnel within range Reynolds numbers from 2284 8893, based edge D prism, and PS = 0.2D–0.8D. results show that peak vibration amplitude prism initially rises then gradually declines with increasing PS. Particularly, maximum observed at 0.5D is improved by approximately 1.9 times compared square Within speed investigated, experiences three modes: initial branch vortex-induced vibration, transition, galloping. will cause vibrations reach galloping mode earlier As modes wake flow structures shift 2S shedding mode, where two single vortices are shed per cycle, 2P characterized pairs cycle. For finite-length phenomenon vortex splitting due upwash downwash flows. Before surpasses critical value, lateral reattachment vanishes length, leading decrease shear layer curvature separating bubble size, while enhancing negative pressure strength. However, exceeding value allows reattachment, reducing amplitude. This explains why efficiency non-monotonic.

Language: Английский

Citations

1
The Effect of the Layout of a Rigid Splitter Plate on the Flow-Induced Vibration of a Downstream Cylinder Subjected to Wake Flow DOI Creative Commons
Ruan Li,

Dingyong Yu,

Jian Bao

et al.

Journal of Marine Science and Engineering, Journal Year: 2023, Volume and Issue: 11(11), P. 2138 - 2138

Published: Nov. 9, 2023

In this study, the effect of additional positions rigid splitter plates on response characteristics tandem cylinders at a Reynolds number 150 and fixed distance ratio 5.0 was numerically investigated via computational fluid dynamics (CFD) method. Four layouts for cylinder–plate body, including downstream cylinder (DC), body with wake side plate (DCP), plate–cylinder an incoming flow (DPC), plate–cylinder–plate double-sided (DPCP), are considered. The results show that attached to or can suppress vibration in specific reduced velocity range (4.0 < Ur ≤ 10.0). Compared DC, maximum amplitude DPC DCP lock-in region is by 30.8% 47.4%, bandwidth also significantly narrower. layer separation point upstream moves upon adding both sides, resulting shear DPCP completely parallel free flow, while 93.6%, which realizes best stream-induced suppression.

Language: Английский

Citations

3
Effect of a splitter plate on the performance of magnetostrictive flow-induced vibrational power generator using a cantilevered circular cylinder DOI Creative Commons

Takuma SHIMA,

Takahiro KIWATA,

Sotaro TAKEUCHI

et al.

Transactions of the JSME (in Japanese), Journal Year: 2024, Volume and Issue: 90(933), P. 23 - 00257

Published: Jan. 1, 2024

In order to improve a vibrational power generator using magnetostrictive material, i.e., Iron-gallium alloy, and flow-induced vibration of cantilevered cylinder, fixed splitter plate was installed behind circular cylinder. Effects gap between cylinder on the performance response amplitude, vortex shedding frequency were investigated through wind tunnel experiments. Flow visualizations around also conducted by smoke-wire method high-speed camera. The test models had span length L 200 mm, 300 mm 400 mm. diameter D 40 A with thickness 2 center model G varied from 8 104 For small ratio G/D ≤ 0.6, galloping occurred. From smoke wire visualization, it related that upstream flow went along side surface inner circulatory generated near gap. As result, accelerated gap-flow occurred negative pressure periodically upper or lower wall large ≥ 1.2, did not occur, amplitude became similar without plate. generation having = 0.2 largest. However, onset velocity larger than other cylinders gaps.

Language: Английский

Citations

0
Three-dimensional numerical analysis of a vertical axis autorotation current turbine (VAACT): Effects of lateral blockage and free surface DOI
Hao Wu, Shuojia Yang, Enhao Wang

et al.

Applied Ocean Research, Journal Year: 2024, Volume and Issue: 150, P. 104138 - 104138

Published: July 27, 2024

Language: Английский

Citations

0
Efficiently Harvesting Low-Speed Wind Energy by a Novel Bi-Stable Piezoelectric Energy Harvester from Vortex-Induced Vibration and Galloping DOI
Zhiyong Zhou,

Di Cao,

Haobo Huang

et al.

Published: Jan. 1, 2023

Designing low-cost and simple harvesters to convert natural wind energy into electricity is regarded as a promising method realize the self-powering of node sensors in Internet Things. However, environmental usually has low varying speed, so its hard be harvested efficiently. To overcome this difficulty, new bi-stable harvester proposed, which can excited execute inter-well oscillations under hybrid effects vortex-induced vibration galloping. The bi-stability realized by introducing three magnets. efficiently harness low-speed energy, cantilever beam equipped with square sectioned bluff body at tip, two foam balls middle part. simulations reveal fluid fields around balls. These results demonstrate that induced vortex causes swing, subsequently driving piezoelectric oscillate jump. potential force-displacement relationship proposed are obtained. prototype fabricated corresponding verification experiment carried out tunnel. indicate extracts executing snap-through or oscillations. Especially, very speeds, although executes same type intra-well motion linear counterpart, output voltage much higher due magnetic interaction bi-stability.

Language: Английский

Citations

0
Suppression of Flow-Induced Vibration of Three Tandem Cylinders by Helical Strakes Under Wake Induced Galloping DOI

Bowen Tang,

Xiantao Fan, Jiawei Wang

et al.

Published: Jan. 1, 2023

Flow-induced vibration (FIV) is an important phenomenon that frequently occurs in practical scenarios, such as chemical towers, chimneys, risers, and offshore structures. Employing effective methods to control FIV crucial for ensuring the safety long-term operation of engineering Due limitations current passive techniques adequately suppressing wake-induced galloping (WIG) tandem cylinders, seven different types helical strakes with varying heights G, pitches P, cross-sectional shapes (square “S”, involute “I”, D-shaped “D”) were designed. Experimental conducted a wind tunnel investigate dynamic responses cylinders (m*ξ=0.09) at spacings, resulting three modes. The amplitude, frequency, three-dimensional computational fluid dynamics (CFD) simulations performed analyze configurations strakes. It was discovered can effectively suppress multi-frequency instability bare cylinders. For speeds U < 6m/s, "S" strake achieved suppression efficiency up 665%. Moreover, larger pitch led less flow interference on spanwise height, significant effects. Furthermore, it observed has stronger influence boundary layer formation compared "D" strake. This results weaker shedding vortices separation point due absence negative pressure gradient shear layer, thus revealing mechanisms cross-sections cylinder dynamics.

Language: Английский

Citations

0