Numerical simulation of flow over flapping wings in tandem: Wingspan effects

Jurado, R.; Arranz, Gonzalo; Flores, Oscar; García-Villalba, Manuel

doi:10.1063/5.0080376

Cited by 12 publications

(6 citation statements)

References 55 publications

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“…More specifically, we speculate that a shorter rear flipper (lower ) would be able to avoid the disturbances of the front wingtip, functioning completely within the quasi-2-D stream. In fact, this strategy can lead to an increase of by up to in dragonfly-inspired concepts (Jurado et al., 2022) and it was likely used by certain plesiosaur species (O'Keefe, 2001).…”

Section: Resultsmentioning

confidence: 99%

“…Contemporary literature on finite wings of varying AR often focuses on single flapping configurations (Hammer, Garmann, & Visbal, 2021;Zhong, Han, Moored, & Quinn, 2021;Zurman-Nasution et al, 2021b) with only a few studies related to tandem arrangements (Arranz, Flores, & Garcia-Villalba, 2020;Jurado, Arranz, Flores, & García-Villalba, 2022). A key feature of the above is the presence of tip vortices that transform the 2-D wake into a complex chain of ring-like formations (Li, Pan, Zhao, Ma, & Wang, 2018;Shao et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

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Effect of aspect ratio on the propulsive performance of tandem flapping foils

Lagopoulos

Weymouth

Ganapathisubramani

2023

Flow

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In this work, we describe the impact of aspect ratio ( $AR$ ) on the performance of optimally phased, identical flapping flippers in a tandem configuration. Three-dimensional simulations are performed for seven sets of single and tandem finite foils at a moderate Reynolds number, with thrust producing, heave-to-pitch coupled kinematics. Increasing slenderness (or $AR$ ) is found to improve thrust coefficients and thrust augmentation but the benefits level off towards higher values of $AR$ . However, the propulsive efficiency shows no significant change with increasing $AR$ , while the hind foil outperforms the single by a small margin. Further analysis of the spanwise development and propagation of vortical structures allows us to gain some insights into the mechanisms of these wake interactions and provide valuable information for the design of novel biomimetic propulsion systems.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of aspect ratio on the propulsive performance of tandem flapping foils

Lagopoulos

Weymouth

Ganapathisubramani

2023

Flow

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“…Note that the definition for the power is such that no extraction of energy from the fluid is considered (Berman & Wang 2007;Vejdani et al 2018;Jurado et al 2022). Figure 4(a) shows the temporal evolution of the required input power for the four stereotypical cases with A = 4.…”

Section: Force Coefficientsmentioning

confidence: 99%

Fluid–structure resonance in spanwise-flexible flapping wings

et al. 2023

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We report direct numerical simulations of the flow around a spanwise-flexible wing in forward flight. The simulations were performed at $Re=1000$ for wings of aspect ratio 2 and 4 undergoing a heaving and pitching motion at Strouhal number $St_c\approx 0.5$ . We have varied the effective stiffness of the wing $\varPi _1$ while keeping the effective inertia constant, $\varPi _0=0.1$ . It has been found that there is an optimal aerodynamic performance of the wing linked to a damped resonance phenomenon, that occurs when the imposed frequency of oscillation approaches the first natural frequency of the structure in the fluid, $\omega _{n,f}/\omega \approx 1$ . In that situation, the time-averaged thrust is maximum, increasing by factor 2 with respect to the rigid case with an increase in propulsive efficiency of approximately 15 %. This enhanced aerodynamic performance results from the combination of larger effective angles of attack of the outboard wing sections and a delayed development of the leading edge vortex. With increasing flexibility beyond the resonant frequency, the aerodynamic performance drops significantly, in terms of both thrust production and propulsive efficiency. The cause of this drop lies in the increasing phase lag between the deflection of the wing and the heaving/pitching motion, which results in weaker leading edge vortices, negative effective angles of attack in the outboard sections of the wing, and drag generation in the first half of the stroke. Our results also show that flexible wings with the same $\omega _{n,f}/\omega$ but different aspect ratio have the same aerodynamic performance, emphasizing the importance of the structural properties of the wing for its aerodynamic performance.

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“…At present, the research methods of bionic flapping-foil propulsion technology are mainly numerical simulations and experimental research. The numerical simulation method has promoted our understanding of bionic flapping-foil propulsion to a certain extent [ 19 , 20 , 21 ]. Pedro et al [ 22 ] used the Computational Fluid Dynamics (CFD) method to study two-dimensional flapping propulsion characteristics.…”

Section: Introductionmentioning

confidence: 99%

Effect of Frequency–Amplitude Parameter and Aspect Ratio on Propulsion Performance of Underwater Flapping-Foil

Ding,

Chen,

Zhu

et al. 2024

Biomimetics

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The propulsion system is the core component of unmanned underwater vehicles. The flapping propulsion method of marine animals’ flippers, which allows for flexibility, low noise, and high energy utilization at low speeds, can provide a new perspective for the development of new propulsion technology. In this study, a new experimental flapping propulsion apparatus that can be installed in both directions has been constructed. The guide rail slider mechanism can achieve the retention of force in the direction of movement, thereby decoupling thrust, lift, and torque. Subsequently, the motion parameters of frequency–amplitude related to the thrust and lift of a bionic flapping-foil are scrutinized. A response surface connecting propulsion efficiency and these motion parameters is formulated. The highest efficiency of the flapping-foil propulsion is achieved at a frequency of 2 Hz and an amplitude of 40°. Furthermore, the impact of the installation mode and the aspect ratio of the flapping-foil is examined. The reverse installation of the swing yields a higher thrust than the forward swing. As the chord length remains constant and the span length increases, the propulsive efficiency gradually improves. When the chord length is extended to a certain degree, the propulsion efficiency exhibits a parabolic pattern, increasing initially and then diminishing. This investigation offers a novel perspective for the bionic design within the domain of underwater propulsion. This research provides valuable theoretical guidance for bionic design in the underwater propulsion field.

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Numerical simulation of flow over flapping wings in tandem: Wingspan effects

Cited by 12 publications

References 55 publications

Effect of aspect ratio on the propulsive performance of tandem flapping foils

Effect of aspect ratio on the propulsive performance of tandem flapping foils

Fluid–structure resonance in spanwise-flexible flapping wings

Effect of Frequency–Amplitude Parameter and Aspect Ratio on Propulsion Performance of Underwater Flapping-Foil

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