Biomimetics

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22 pages, 18178 KiB

Open AccessArticle

The Effect of Hindwing Trajectories on Wake–Wing Interactions in the Configuration of Two Flapping Wings in Tandem

by Xu He, Chao Wang, Pan Jia and Zheng Zhong

Biomimetics 2024, 9(7), 406; https://doi.org/10.3390/biomimetics9070406 - 4 Jul 2024

Viewed by 1077

The present investigations on tandem wing configurations primarily revolve around the effects of the spacing L and the phase difference

φ

between the forewing and the hindwing on aerodynamic performance. However, in nature, organisms employing biplane flight, such as dragonflies, demonstrate the ability [...] Read more.

The present investigations on tandem wing configurations primarily revolve around the effects of the spacing L and the phase difference

φ

between the forewing and the hindwing on aerodynamic performance. However, in nature, organisms employing biplane flight, such as dragonflies, demonstrate the ability to achieve superior aerodynamic performance by flexibly adjusting their flapping trajectories. Therefore, this study focuses on the effects of

φ

, as well as the trajectory of the hindwing, on aerodynamic performance. By summarizing four patterns of wake–wing interaction processes, it is indicated that

φ = - 90^{\circ}

and

0^{\circ}

enhances the thrust of the hindwing, while

φ = 90^{\circ}

and

180^{\circ}

result in reductions. Furthermore, the wake–wing interactions and shedding modes are summarized corresponding to three kinds of trajectories, including elliptical trajectories, figure-eight trajectories, and double figure-eight trajectories. The results show that the aerodynamic performance of the elliptical trajectory is similar to that of the straight trajectory, while the figure-eight trajectory with positive surging motion significantly enhances the aerodynamic performance of the hindwing. Conversely, the double-figure-eight trajectory degrades the aerodynamic performance of the hindwing. Full article

(This article belongs to the Special Issue Computational Biomechanics and Biomimetics in Flying and Swimming)

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31 pages, 43565 KiB

Open AccessArticle

Numerical Investigation of Dimensionless Parameters in Carangiform Fish Swimming Hydrodynamics

by Marianela Machuca Macías, José Hermenegildo García-Ortiz, Taygoara Felamingo Oliveira and Antonio Cesar Pinho Brasil Junior

Biomimetics 2024, 9(1), 45; https://doi.org/10.3390/biomimetics9010045 - 11 Jan 2024

Cited by 2 | Viewed by 2478

Abstract

Research into how fish and other aquatic organisms propel themselves offers valuable natural references for enhancing technology related to underwater devices like vehicles, propellers, and biomimetic robotics. Additionally, such research provides insights into fish evolution and ecological dynamics. This work carried out a [...] Read more.

Research into how fish and other aquatic organisms propel themselves offers valuable natural references for enhancing technology related to underwater devices like vehicles, propellers, and biomimetic robotics. Additionally, such research provides insights into fish evolution and ecological dynamics. This work carried out a numerical investigation of the most relevant dimensionless parameters in a fish swimming environment (Reynolds

R e

, Strouhal

S t

, and

S l i p

numbers) to provide valuable knowledge in terms of biomechanics behavior. Thus, a three-dimensional numerical study of the fish-like lambari, a BCF swimmer with carangiform kinematics, was conducted using the URANS approach with the k-

ω

-SST transition turbulence closure model in the OpenFOAM software. In this study, we initially reported the equilibrium Strouhal number, which is represented by

S t^{*}

, and its dependence on the Reynolds number, denoted as

R e

. This was performed following a power–law relationship of

S t \propto R e^{(- α)}

. We also conducted a comprehensive analysis of the hydrodynamic forces and the effect of body undulation in fish on the production of swimming drag and thrust. Additionally, we computed propulsive and quasi-propulsive efficiencies, as well as examined the influence of the Reynolds number and

S l i p

number on fish performance. Finally, we performed a vortex dynamics analysis, in which different wake configurations were revealed under variations of the dimensionless parameters

S t

,

R e

, and

S l i p

. Furthermore, we explored the relationship between the generation of a leading-edge vortex via the caudal fin and the peak thrust production within the motion cycle. Full article

(This article belongs to the Special Issue Computational Biomechanics and Biomimetics in Flying and Swimming)

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17 pages, 4704 KiB

Open AccessEditor’s ChoiceArticle

Numerical Investigation of Odor-Guided Navigation in Flying Insects: Impact of Turbulence, Wingbeat-Induced Flow, and Schmidt Number on Odor Plume Structures

by Menglong Lei, Mark A. Willis, Bryan E. Schmidt and Chengyu Li

Biomimetics 2023, 8(8), 593; https://doi.org/10.3390/biomimetics8080593 - 6 Dec 2023

Cited by 5 | Viewed by 1901

Abstract

Odor-guided navigation is fundamental to the survival and reproductive success of many flying insects. Despite its biological importance, the mechanics of how insects sense and interpret odor plumes in the presence of complex flow fields remain poorly understood. This study employs numerical simulations [...] Read more.

Odor-guided navigation is fundamental to the survival and reproductive success of many flying insects. Despite its biological importance, the mechanics of how insects sense and interpret odor plumes in the presence of complex flow fields remain poorly understood. This study employs numerical simulations to investigate the influence of turbulence, wingbeat-induced flow, and Schmidt number on the structure and perception of odor plumes by flying insects. Using an in-house computational fluid dynamics solver based on the immersed-boundary method, we solve the three-dimensional Navier–Stokes equations to model the flow field. The solver is coupled with the equations of motion for passive flapping wings to emulate wingbeat-induced flow. The odor landscape is then determined by solving the odor advection–diffusion equation. By employing a synthetic isotropic turbulence generator, we introduce turbulence into the flow field to examine its impact on odor plume structures. Our findings reveal that both turbulence and wingbeat-induced flow substantially affect odor plume characteristics. Turbulence introduces fluctuations and perturbations in the plume, while wingbeat-induced flow draws the odorant closer to the insect’s antennae. Moreover, we demonstrate that the Schmidt number, which affects odorant diffusivity, plays a significant role in odor detectability. Specifically, at high Schmidt numbers, larger fluctuations in odor sensitivity are observed, which may be exploited by insects to differentiate between various odorant volatiles emanating from the same source. This study provides new insights into the complex interplay between fluid dynamics and sensory biology and behavior, enhancing our understanding of how flying insects successfully navigate using olfactory cues in turbulent environments. Full article

(This article belongs to the Special Issue Computational Biomechanics and Biomimetics in Flying and Swimming)

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20 pages, 7655 KiB

Open AccessEditor’s ChoiceArticle

Effect of Hindwings on the Aerodynamics and Passive Dynamic Stability of a Hovering Hawkmoth

by Ryusuke Noda, Toshiyuki Nakata and Hao Liu

Biomimetics 2023, 8(8), 578; https://doi.org/10.3390/biomimetics8080578 - 1 Dec 2023

Cited by 5 | Viewed by 2224

Abstract

Insects are able to fly stably in the complex environment of the various gusts that occur in nature. In addition, many insects suffer wing damage in their lives, but many species of insects are capable of flying without their hindwings. Here, we evaluated [...] Read more.

Insects are able to fly stably in the complex environment of the various gusts that occur in nature. In addition, many insects suffer wing damage in their lives, but many species of insects are capable of flying without their hindwings. Here, we evaluated the effect of hindwings on aerodynamics using a Navier–Stokes-based numerical model, and then the passive dynamic stability was evaluated by coupling the equation of motion in three degrees of freedom with the aerodynamic forces estimated by the CFD solver under large and small perturbation conditions. In terms of aerodynamic effects, the presence of the hindwings slightly reduces the efficiency for lift generation but enhances the partial LEV circulation and increases the downwash around the wing root. In terms of thrust, increasing the wing area around the hindwing region increases the thrust, and the relationship is almost proportional at the cycle-averaged value. The passive dynamic stability was not clearly affected by the presence of the hindwings, but the stability was slightly improved depending on the perturbation direction. These results may be useful for the integrated design of wing geometry and flight control systems in the development of flapping-winged micro air vehicles. Full article

(This article belongs to the Special Issue Computational Biomechanics and Biomimetics in Flying and Swimming)

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16 pages, 1700 KiB

Open AccessArticle

POD-Galerkin FSI Analysis for Flapping Motion

by Shigeki Kaneko and Shinobu Yoshimura

Biomimetics 2023, 8(7), 523; https://doi.org/10.3390/biomimetics8070523 - 3 Nov 2023

Viewed by 1395

Abstract

FSI simulations of flapping motions have been widely investigated to develop a flapping-wing micro air vehicle. Because an intensive parametric study is important for the product design, a computationally efficient model is required. The purpose of the present study was to develop a [...] Read more.

FSI simulations of flapping motions have been widely investigated to develop a flapping-wing micro air vehicle. Because an intensive parametric study is important for the product design, a computationally efficient model is required. The purpose of the present study was to develop a reduced-order model of flapping motion. Among the various methods available to solve FSI problems, we employed the Dirichlet–Neumann partitioned iterative method, in which three sub-systems (fluid mesh update, fluid analysis, and structural analysis) are executed. In the proposed analysis system, first, snapshot data of structural displacement, fluid velocity, fluid pressure, and displacement for the fluid mesh update were collected from a high-fidelity FSI analysis. Then, the snapshot data were used to create low-dimensional surrogate systems of the above three sub-systems based on the POD under Galerkin projection (i.e., the POD-Galerkin method). In numerical examples, we considered a two-dimensional FSI problem of simplified flapping motion. The problem was described via two parameters: frequency and amplitude of flapping motion. We demonstrated the effectiveness of the presented reduced-order model in significantly reducing computational time while preserving the desired accuracy. Full article

(This article belongs to the Special Issue Computational Biomechanics and Biomimetics in Flying and Swimming)

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14 pages, 4164 KiB

Open AccessArticle

Mechanical Behavior of Honeybee Forewing with Flexible Resilin Joints and Stripes

by Dan Hou and Zheng Zhong

Biomimetics 2023, 8(6), 451; https://doi.org/10.3390/biomimetics8060451 - 24 Sep 2023

Cited by 2 | Viewed by 1766

Abstract

The flexibility of insect wings should be considered in the design of bionic micro flapping-wing aircraft. The honeybee is an ideal biomimetic object because its wings are small and possess a concise vein pattern. In this paper, we focus on resilin, an important [...] Read more.

The flexibility of insect wings should be considered in the design of bionic micro flapping-wing aircraft. The honeybee is an ideal biomimetic object because its wings are small and possess a concise vein pattern. In this paper, we focus on resilin, an important flexible factor in honeybees’ forewings. Both resilin joints and resilin stripes are considered in the finite element model, and their mechanical behaviors are studied comprehensively. Resilin was found to increase the static deflections in chordwise and spanwise directions by 1.4 times and 1.9 times, respectively. In modal analysis, natural frequencies of the first bending and first torsional modes were found to be decreased significantly—especially the latter, which was reduced from 500 Hz to 217 Hz—in terms of resilin joints and stripes, closely approaching flapping frequency. As a result, the rotational angle amplitude in dynamic responses is remarkable, with an amplification ratio of about six. It was also found that resilin joints and stripes together lead to well-cambered sections and improve the stress concentrations in dynamic deformation. As resilin is widespread in insect wings, the study could help our understanding of the flexible mechanism of wing structure and inspire the development of flexible airfoils. Full article

(This article belongs to the Special Issue Computational Biomechanics and Biomimetics in Flying and Swimming)

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14 pages, 9836 KiB

Open AccessArticle

Power Benefits of High-Altitude Flapping Wing Flight at the Monarch Butterfly Scale

by Chang-kwon Kang, Madhu Sridhar, Rachel Twigg, Jeremy Pohly, Taeyoung Lee and Hikaru Aono

Biomimetics 2023, 8(4), 352; https://doi.org/10.3390/biomimetics8040352 - 8 Aug 2023

Cited by 3 | Viewed by 2631

Abstract

The long-range migration of monarch butterflies, extended over 4000 km, is not well understood. Monarchs experience varying density conditions during migration, ranging as high as 3000 m, where the air density is much lower than at sea level. In this study, we test [...] Read more.

The long-range migration of monarch butterflies, extended over 4000 km, is not well understood. Monarchs experience varying density conditions during migration, ranging as high as 3000 m, where the air density is much lower than at sea level. In this study, we test the hypothesis that the aerodynamic performance of monarchs improves at reduced density conditions by considering the fluid–structure interaction of chordwise flexible wings. A well-validated, fully coupled Navier–Stokes/structural dynamics solver was used to illustrate the interplay between wing motion, aerodynamics, and structural flexibility in forward flight. The wing density and elastic modulus were measured from real monarch wings and prescribed as inputs to the aeroelastic framework. Our results show that sufficient lift is generated to offset the butterfly weight at higher altitudes, aided by the wake-capture mechanism, which is a nonlinear wing–wake interaction mechanism, commonly seen for hovering animals. The mean total power, defined as the sum of the aerodynamic and inertial power, decreased by 36% from the sea level to the condition at 3000 m. Decreasing power with altitude, while maintaining the same equilibrium lift, suggests that the butterflies generate lift more efficiently at higher altitudes. Full article

(This article belongs to the Special Issue Computational Biomechanics and Biomimetics in Flying and Swimming)

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18 pages, 130916 KiB

Open AccessEditor’s ChoiceArticle

The Lift Effects of Chordwise Wing Deformation and Body Angle on Low-Speed Flying Butterflies

by Yan-Hung Fang, Chia-Hung Tang, You-Jun Lin, Szu-I Yeh and Jing-Tang Yang

Biomimetics 2023, 8(3), 287; https://doi.org/10.3390/biomimetics8030287 - 3 Jul 2023

Cited by 4 | Viewed by 2977

Abstract

This work investigates the effects of body angle and wing deformation on the lift of free-flying butterflies. The flight kinematics were recorded using three high-speed cameras, and particle-image velocimetry (PIV) was used to analyze the transient flow field around the butterfly. Parametric studies [...] Read more.

This work investigates the effects of body angle and wing deformation on the lift of free-flying butterflies. The flight kinematics were recorded using three high-speed cameras, and particle-image velocimetry (PIV) was used to analyze the transient flow field around the butterfly. Parametric studies via numerical simulations were also conducted to examine the force generation of the wing by fixing different body angles and amplifying the chordwise deformation. The results show that appropriately amplifying chordwise deformation enhances wing performance due to an increase in the strength of the vortex and a more stabilized attached vortex. The wing undergoes a significant chordwise deformation, which can generate a larger lift coefficient than that with a higher body angle, resulting in a 14% increase compared to a lower chordwise deformation and body angle. This effect is due to the leading-edge vortex attached to the curved wing, which alters the force from horizontal to vertical. It, therefore, produces more efficient lift during flight. These findings reveal that the chordwise deformation of the wing and the body angle could increase the lift of the butterfly. This work was inspired by real butterfly flight, and the results could provide valuable knowledge about lift generation for designing microaerial vehicles. Full article

(This article belongs to the Special Issue Computational Biomechanics and Biomimetics in Flying and Swimming)

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