Physical models and vortex dynamics of swimming and flying: a review

Zhang, Dong; Zhang, Jun-Duo; Huang, Wei‐Xi

doi:10.1007/s00707-022-03192-9

Cited by 12 publications

(9 citation statements)

References 302 publications

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“…The tethered model (Zhang et al. 2022 b ) was employed and the net thrust force is nearly zero, indicating that the present setting is close to the free swimming state. As a result, there is almost no jet in the wake, except at the tip region, which is consistent with that of manta rays (Fish et al.…”

Section: Discussionmentioning

confidence: 76%

“…2015; Zhang et al. 2022 b ). For a tethered model, the net efficiency is always employed in the measurement of flapping foils, which is distinct from the present quasipropulsive efficiency.…”

Section: Discussionmentioning

confidence: 99%

“…Several review papers (Triantafyllou, Triantafyllou & Yue 2000;Lauder 2015;Smits 2019;Zhang, Zhang & Huang 2022b) have introduced comprehensively the recent progresses in the hydrodynamics of aquatic locomotion and aerodynamics of airborne flight. Although study on the flow around real living animals is the most direct approach for understanding biological kinematics and fluid dynamics, the research object is limited to relatively small-size species with low and intermediate Re, such as eels (Tytell 2004;Tytell & Lauder 2004), zebrafish (Guo et al 2022), sunfish (Drucker & Lauder 2000), dragonflies (Thomas et al 2004) and hummingbirds (Pournazeri et al 2013).…”

Section: Introductionmentioning

confidence: 99%

“…However, studying the swimming and flying problems at high Reynolds numbers remains a challenge (Dong et al 2010;Borazjani & Daghooghi 2013;Fish et al 2016). Zhang et al (2022b) summarized the Reynolds numbers employed in approximately 60 studies of aquatic animals (figure 1) and showed that experiments generally were conducted under higher-Re conditions than numerical studies. The Reynolds numbers of most high-fidelity numerical simulations were below 10 4 , due to the high requirement of a fine grid for resolving the boundary layer near the body and the wake flow.…”

Section: Introductionmentioning

confidence: 99%

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Hydrodynamics of a swimming batoid fish at Reynolds numbers up to 148 000

Dong

Huang

2023

J. Fluid Mech.

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Flow around a tethered model of a swimming batoid fish is studied by using the wall-modelled large-eddy simulation in conjunction with the immersed boundary method. A Reynolds number ( $Re$ ) up to 148 000 is chosen, and it is comparable to that of a medium-sized aquatic animal in cruising swimming state. At such a high $Re$ , we provide, to the best of our knowledge, the first evidence of hairpin vortical (HV) structures near the body surface using three-dimensional high-fidelity flow field data. It is observed that such small-scale vortical structures are mainly formed through two mechanisms: the leading-edge vortex (LEV)–secondary filament–HV and LEV–HV transformations in different regions. The HVs create strong fluctuations in the pressure distribution and frequency spectrum. Simulations are also conducted at $Re=1480$ and 14 800 to reveal the effect of Reynolds number. Variations of the flow separation behaviour and local pressure with $Re$ are presented. Our results indicate that low- $Re$ simulations are meaningful when the focus is on the force variation tendency, whereas high- $Re$ simulations are needed when concerning flow fluctuations and turbulence mechanisms.

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Section: Discussionmentioning

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hydrodynamics of a swimming batoid fish at Reynolds numbers up to 148 000

Dong

Huang

2023

J. Fluid Mech.

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“…Fish et al [27] figures out that the eddy current mode and high-efficiency propulsion of the manta ray are obtained through simulation calculations, which are related to the Strouhal number at normal swimming speed. Dong Zhang [28,29] reveals that moderate chordal deformation enhances thrust and improves efficiency, and the tip vortex is the main source of thrust at a high Strouhal number, while a leading-edge vortex and rear-edge vortex will weaken the thrust generation; at a lower Strouhal number, the leading-edge vortex enhances thrust. Heathcote [30] studied the effect of spanwise flexibility on the thrust, lift, and propulsive efficiency using PIV (particle image velocimetry) through water tunnel experiments.…”

Section: Introductionmentioning

confidence: 99%

Effects of Bionic Bone Flexibility on the Hydrodynamics of Pectoral Fins

Cao

Bao

Cao

et al. 2022

JMSE

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Compared with traditional underwater equipment powered by propeller, the manta-ray-inspired vehicle with MPF mode (Median fin/paired fin) has the advantages of stable swimming attitude, high maneuverability, and low noise, etc. As one of the sources of advancing power when the manta-ray-inspired vehicle swims, the flexible deformation of the pectoral fin is an important factor affecting the hydrodynamic performance. In this paper, a mechanical analysis of the two-dimensional flexible pectoral fin using thin wing theory shows that the main factor affecting the hydrodynamic force of the two-dimensional flexible pectoral fin is the level of curvature of the pectoral fin chordal section. By designing a two-stage bionic skeleton at the leading and rear edges of the manta-ray-inspired vehicle, the root–tip section width of the bionic skeleton is used to characterize the level of the bionic pectoral fin’s flexibility, and a tensiometer is used to quantitatively measure the level of flexibility. The root-to-tip ratio of the cross-section was varied to obtain different levels of pectoral fin flexibility, and the hydrodynamic properties of the pectoral fins during flapping were measured using a force sensor and normalized for analysis. The experimental results show that the reduction of the flexibility of the leading edge and the increase of the flexibility of the rear edge are beneficial to the improvement of the thrust performance, and the experimental results are the same as the distribution of the skeletal flexibility in real organisms. Fitting curves of the pectoral fins’ relative flexibility and the normalized thrust/lift show that the flexibility of the pectoral fins has a significant effect on its hydrodynamic force, and a stiffer leading edge and a softer rear edge can improve the hydrodynamic characteristics of the manta-ray-inspired vehicle. Phase differences interacting with flexibility can also enhance bionic pectoral fins’ dynamic properties within 10~30 degree.

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变翼展的仿生扑翼尾迹特征

Liu

Chen

et al. 2023

Acta Mech. Sin.

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Physical models and vortex dynamics of swimming and flying: a review

Cited by 12 publications

References 302 publications

Hydrodynamics of a swimming batoid fish at Reynolds numbers up to 148 000

Hydrodynamics of a swimming batoid fish at Reynolds numbers up to 148 000

Effects of Bionic Bone Flexibility on the Hydrodynamics of Pectoral Fins

变翼展的仿生扑翼尾迹特征

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