Stereo PIV measurement of a finite, flapping rigid plate in hovering condition

Suryadi, Alexandre; Ishii, Takayuki; Obi, Shinnosuke

doi:10.1007/s00348-009-0814-3

Cited by 17 publications

(10 citation statements)

References 18 publications

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“…An example of the PIV calculation points on a raw picture can be seen in Figure 3. The uncertainty of this measurement technique was previously estimated to be within 5% in the streamwise direction and 2.5% in the transverse direction, of the freestream velocity [13][14][15]. Similar to Part I, approximately 48 s of the flow was captured by 24,000 PIV realizations.…”

Section: Materials and Methodologymentioning

confidence: 95%

See 1 more Smart Citation

Flow Field Measurement of Laboratory-Scaled Cross-Flow Hydrokinetic Turbines: Part II—The Near-Wake of Twin Turbines in Counter-Rotating Configurations

Doan

Kawata

Obi

2021

JMSE

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Cross-flow hydrokinetic turbines have sparked interest among fluid dynamicists for their potential for power enhancement in paired configuration. Following the first part of a laboratory-scaled turbine wake measurement project, this second part presents a monoscopic particle image velocimetry measurement of the near-wake of two cross-flow hydrokinetic turbines in six different counter-rotating configurations. The turbines operated in a small water flume at an average diameter-based Reynolds number of 2×104 with the incoming streamwise velocity of 0.316 m/s. The six configurations included two turbine separation distances, two turbine phase angles differences, and two different relative incoming flow angles. Similar to the observation of the single turbine configurations in part I, a correlation between flow field structures and the corresponding power output was observed. Effects of each parameter of the counter-rotating configurations are further discussed, which suggest guidelines for setting up multiple devices in a power farm. This article is accompanied by all full numeric data sets and videos of the results.

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Section: Materials and Methodologymentioning

confidence: 95%

“…Similar to Part I, approximately 48 s of the flow was captured by 24,000 PIV realizations. The raw pictures were processed by an in-house developed program described in [13,14]. All the results were also extracted at the 4 arbitrary points for the Fast Fourier Transformation (FFT) analyses and result convergence evaluation.…”

Section: Materials and Methodologymentioning

confidence: 99%

Flow Field Measurement of Laboratory-Scaled Cross-Flow Hydrokinetic Turbines: Part II—The Near-Wake of Twin Turbines in Counter-Rotating Configurations

Doan

Kawata

Obi

2021

JMSE

Self Cite

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“…As shown in Figure 3a, the plate's passive flapping is around its fixed leading edge. In the process of passive flapping, the plate loses its initial flat status, which is obviously different from the rigid plate's flapping [44,45]. Moreover, the motion of the flexible plate apparently contains the deformation streamwise and the deformation spanwise.…”

Section: Validationmentioning

confidence: 99%

Coupling Motion and Energy Harvesting of Two Side-by-Side Flexible Plates in a 3D Uniform Flow

2016

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Abstract:The fluid-structure interaction problems of two side-by-side flexible plates with a finite aspect ratio in a three-dimensional (3D) uniform flow are numerically studied. The plates' motions are entirely passive under the force of surrounding fluid. By changing the aspect ratio and transverse distance, the coupling motions, drag force and energy capture performance are analyzed. The mechanisms underlying the plates' motion and flow characteristics are discussed systematically. The adopted algorithm is verified and validated by the simulation of flow past a square flexible plate. The results show that the plate's passive flapping behavior contains transverse and spanwise deformation, and the flapping amplitude is proportional to the aspect ratio. In the side-by-side configuration, three distinct coupling modes of the plates' motion are identified, including single-plate mode, symmetrical flapping mode and decoupled mode. The plate with a lower aspect ratio may suffer less drag force and capture less bending energy than in the isolated situation. The optimized selection for obtaining higher energy conversion efficiency is the plate flapping in single-plate mode, especially the plate with a higher aspect ratio. The findings of this work provide several new physical insights into the understanding of fish schooling and are expected to inspire the developments of underwater robots or energy harvesters.

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“…The studies reported by Weis-Fogh, 1 Lighthill, 2 Dickinson and G€ otz, 3 Wootton, 4 Dickinson, 5 Ellington et al, 6 Ellington, 7 Dickinson et al, 8 and Sun and Tang 9 were immense in contribution and laid a path to understand flapping flight. Hong and Altman, 10,11 Jardin et al, 12 Massey et al, 13 Krashanitsa et al, 14 Mazaheri and Ebrahimi, [15][16][17] Suryadi et al, 18 Jones and Babinsky, 19 Lua et al, 20 Ozen and Rockwell, 21 Curtis et al, 22 Granlund et al, 23 Goli et al, 24 and Lua et al 25 report various studies performed on flapping wings with an intention to visualize and understand the flow field behavior of heaving, pitching, and combined heaving-pitching of rigid airfoils, flat plates, and wings of low aspect ratio (AR).…”

Section: Introductionmentioning

confidence: 99%

Vortex filamentation and fragmentation phenomena in flapping motion and effect of aspect ratio and frequency on global strain, rotation, and enstrophy

Goli

Roy

2019

International Journal of Micro Air Vehicles

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In the present study, flow field around rigid flat plate wings executing main flapping motion has been studied using phaselocked two-dimensional particle image velocimetry measurements. Experiments have been conducted in water as a fluid medium for an asymmetric upper-lower stroke single degree of freedom main flapping motion. Two different aspect ratio (1.5 and 1.0) rectangular wings at 1.5 and 2.0 Hz flapping frequency in hovering flight mode (advance ratio, J ¼ 0), zero wing pitch angle, and chord-based Reynolds number of the order of 10 4 have been studied. Velocity field and vorticity field with k 2 criterion information have been obtained for the complete stroke in great detail to reveal the minute aspects of flow dynamics. The flow features during the downstroke and upstroke have been observed to be consistent for all four cases investigated. The predominant characteristic of the flow during downstroke and upstroke has been referred to as vortex filamentation and fragmentation phenomena. Quantities such as circulation, rate of strain, rate of rotation, and enstrophy have been studied to identity the effect of minor change in aspect ratio and flapping frequency. It is found that for higher aspect ratio wing hyperbolic behavior is predominant except for end of downstroke and beginning of upstroke where elliptic behavior is observed. For lower aspect ratio, wing elliptic behavior is predominant except for end of upstroke and beginning of downstroke where hyperbolic behavior is seen. The hyperbolic behavior became stronger at higher frequency. From enstrophy distribution it is evident that higher frequencies play a more dominant role than aspect ratio in determining the budget.

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Stereo PIV measurement of a finite, flapping rigid plate in hovering condition

Cited by 17 publications

References 18 publications

Flow Field Measurement of Laboratory-Scaled Cross-Flow Hydrokinetic Turbines: Part II—The Near-Wake of Twin Turbines in Counter-Rotating Configurations

Flow Field Measurement of Laboratory-Scaled Cross-Flow Hydrokinetic Turbines: Part II—The Near-Wake of Twin Turbines in Counter-Rotating Configurations

Coupling Motion and Energy Harvesting of Two Side-by-Side Flexible Plates in a 3D Uniform Flow

Vortex filamentation and fragmentation phenomena in flapping motion and effect of aspect ratio and frequency on global strain, rotation, and enstrophy

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