Flow-structure interactions of two parallel inverted flags with small separation distances in a water tunnel

Hu, Yao-Wei; Feng, Li-Hao; Wang, Jinjun

doi:10.1016/j.jfluidstructs.2020.102960

Cited by 5 publications

(4 citation statements)

References 28 publications

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“…Recently, the concurrent operation of two or more inverted flags has started to gain attention, with two main configurations being considered: side-by-side (see Figure 1 b) [ 45 , 46 , 47 , 48 , 49 , 50 , 51 ] and tandem (see Figure 1 b) [ 51 , 52 , 53 ] configurations within the horizontal plane. Huertas-Cerdeira et al [ 45 ] experimentally studied the dynamic response of side-by-side inverted flags, with a transverse distance larger than double the length of the flag, demonstrating that the maximum angular amplitude is 36% higher than that of a single flag.…”

Section: Introductionmentioning

confidence: 99%

“…Huertas-Cerdeira et al [ 45 ] experimentally studied the dynamic response of side-by-side inverted flags, with a transverse distance larger than double the length of the flag, demonstrating that the maximum angular amplitude is 36% higher than that of a single flag. Hu et al [ 50 ] attributed this increase to the flapping promotion resulting from the leading-edge vortex (LEV) behind the adjacent flag. On the other hand, Huang et al [ 52 ] investigated the tandem configuration and found through numerical simulations that a destructive vortex merging reduces the flapping amplitude of the downstream inverted flag by 50% compared to a single flag.…”

Section: Introductionmentioning

confidence: 99%

“…To the best of the authors' knowledge, there has not been an in-depth study into multiple flags arranged side-by-side on the same pole, hence creating the motivation for this work. Our aim is, therefore, to study the coupling interaction between inverted flags in a Recently, the concurrent operation of two or more inverted flags has started to gain attention, with two main configurations being considered: side-by-side (see Figure 1b) [45][46][47][48][49][50][51] and tandem (see Figure 1b) [51][52][53] configurations within the horizontal plane. Huertas-Cerdeira et al [45] experimentally studied the dynamic response of sideby-side inverted flags, with a transverse distance larger than double the length of the flag, demonstrating that the maximum angular amplitude is 36% higher than that of a single flag.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Wind Energy Harvesting with Vertically Aligned Piezoelectric Inverted Flags

Yang,

Cioncolini,

Revell

et al. 2023

Sensors

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Wind-energy-harvesting generators based on inverted flag architecture are an attractive option to replace batteries in low-power wireless electronic devices and deploy-and-forget distributed sensors. This study examines two important aspects that have been overlooked in previous research: the interaction between an inverted flag and a neighboring solid boundary and the interaction among multiple contiguous inverted flags arranged in a vertical row. Systematic tests have been carried out with metal-only ‘baseline’ flags as well as a ‘harvester’ variant, i.e., the baseline metal flag covered with PVDF (polyvinylidene difluoride) piezoelectric polymer elements. In each case, dynamic response and power generation were measured and assessed. For baseline metal flags, the same qualitative trend is observed when the flag approaches an obstacle, whether this is a wall or another flag. As the gap distance reduces, the wind speed range at which flapping occurs gradually shrinks and shifts towards lower velocities. The increased damping introduced by attaching PVDF elements to the baseline metal flags led to a considerable narrowing of the flapping wind speed range, and the wall-to-flag or flag-to-flag interaction led to a power reduction of up to one order of magnitude compared to single flags. The present findings highlight the strong dependence of the power output on the flapping frequency, which decreases when the flag approaches a wall or other flags mounted onto the same pole. Minimum flag-to-flag and flag-to-wall spacing values are suggested for practical applications to avoid power reduction in multi-flag arrangements (2-3H and 1-2H respectively, where H is flag height).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Wind Energy Harvesting with Vertically Aligned Piezoelectric Inverted Flags

Yang,

Cioncolini,

Revell

et al. 2023

Sensors

View full text Add to dashboard Cite

show abstract

“…Therefore, a water tunnel could provide relatively precise and consistent experimental data to measure complex fluid flow characteristics [8]. The utilization of water tunnels and PIV has been demonstrated to be invaluable in various practical applications such as coastal study [9], turbulence study [10], micro air vehicle study [11], and fluidstructure interaction [12]- [13].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Simple-Built and Low-Speed Water Tunnel as a Platform for Studying Fluid Flow Using PIV Measurements

Darmawan¹,

William²,

Gunawan³

2022

JMechE

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We present a thorough experimental investigation of a simple-built low-speed water tunnel that could facilitate the study of some of the primary fluid dynamic concepts based on quantitative flow measurements using Particle Image Velocimetry (PIV). The water tunnel system is designed and built using a simple arrangement of a double reservoir tank and a centrifugal pump that drives the fluid flow at low speed into a square cross-sectional and relatively short test section. The study shows that the system reasonably and steadily generates fully developed flows inside the test section with <20% of point velocity variations. Based on the fluid-structure tests, it is also observed that the system could produce moderately consistent boundary layer separation phenomena with the variance of the area mean vorticity within 25%. With this performance, we show that the system fulfills the essential requirement to be used as a simple, easy-to-operate, and easy-to-maintain educational platform to study fluid dynamic phenomena related to the interaction of a static sub-merged object and fluid flow.

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Flow-structure interactions of multiple inverted flags in different arrangements

Feng

Wang

2021

Exp Fluids

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Flow-structure interactions of two parallel inverted flags with small separation distances in a water tunnel

Cited by 5 publications

References 28 publications

Wind Energy Harvesting with Vertically Aligned Piezoelectric Inverted Flags

Wind Energy Harvesting with Vertically Aligned Piezoelectric Inverted Flags

Experimental Investigation of Simple-Built and Low-Speed Water Tunnel as a Platform for Studying Fluid Flow Using PIV Measurements

Flow-structure interactions of multiple inverted flags in different arrangements

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