Propulsive performance of a passively flapping plate in a uniform flow

Han, Rui; Zhang, Jie; Cao, Linlin; Lu, Xi‐Yun

doi:10.1016/s1001-6058(15)60509-1

Cited by 6 publications

(4 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…So, the swimming velocity of biological prototypes was usually set as a constant in previous numerical studies [17,18]. To simplify the problem of biological propulsion, the wings or fins of animals living in fluid media can be abstracted to bionic foils [19][20][21][22]. Study of the hydrodynamic mechanism of bionic foils would help to reveal the hydrodynamic mechanism of biological prototypes [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Study on the Hydrodynamic Performance of Typical Underwater Bionic Foils with Spanwise Flexibility

2017

View full text Add to dashboard Cite

Bionic foils are usually similar in shape to the locomotive organs of animals living in fluid media, which is helpful in the analysis of the motion mode and hydrodynamic mechanisms of biological prototypes. With the design of underwater vehicles as the research background, bionic foils are adopted as research objects in this paper. A geometric model and a motion model are established depending on the biological prototype. In the model, two typical bionic foils-a NACA foil and a crescent-shaped foil-are chosen as research objects. Simulations of the bionic foils are performed using a numerical method based on computational fluid dynamics software. The hydrodynamic forces acting on the foils and flow field characteristics behind the foils are used to analyze the propulsion performance and hydrodynamic mechanism. Furthermore, a spanwise flexibility model is introduced into the motion model. Next, the hydrodynamic mechanism is further analyzed on the basis of hydrodynamic forces and flow field characteristics with different spanwise flexibility parameters. Finally, an experimental verification platform is designed and built to verify the reliability of the numerical results. Agreement between the experimental and numerical results indicates that the numerical results are reliable and that the analysis of the paper is reasonable.

show abstract

Section: Introductionmentioning

confidence: 99%

Study on the Hydrodynamic Performance of Typical Underwater Bionic Foils with Spanwise Flexibility

2017

View full text Add to dashboard Cite

show abstract

“…The aerodynamic load, which is applied at the 40% chord line, increases quadratically from zero at the root to A 0 at the tip. The 40% chord line is chosen to roughly represent the chordwise aerodynamic load center which might vary from the 1/4 chord to the 1/2 chord in reality (Han et al, 2015). The inertial load distributes uniformly along the chord direction and linearly increases from zero at the root to B 0 at the tip.…”

Section: Validation Of the Proposed Twist Modelmentioning

confidence: 99%

“…The prescribed pitching motion helps the simulation to converge easier and reduces the computational cost. However, the power consumption of flapping wings with prescribed and passive pitching motion can differ dramatically (Han et al, 2015). In this work, we propose a computationally efficient FSI model to study the (optimal) twist of flapping wings.…”

Section: Introductionmentioning

confidence: 99%

An efficient fluid–structure interaction model for optimizing twistable flapping wings

Goosen

Keulen

2017

Journal of Fluids and Structures

View full text Add to dashboard Cite

Spanwise twist can dominate the deformation of flapping wings and alters the aerodynamic performance and power efficiency of flapping wings by changing the local angle of attack. Traditional Fluid-Structure Interaction (FSI) models, based on Computational Structural Dynamics (CSD) and Computational Fluid Dynamics (CFD), have been used to investigate the influence of twist on the power efficiency. However, it is impractical to use them for twist optimization due to the high computational cost. On the other hand, it is of great interest to study the optimal twist of flapping wings. In this work, we propose a computationally efficient FSI model based on an analytical twist model and a quasi-steady aerodynamic model which replace the expensive CSD and CFD methods. The twist model uses a polynomial to describe the change of the twist angle along the span. The polynomial order is determined based on a convergence study. A nonlinear plate model is used to evaluate the structural response of the twisted wing. The adopted quasi-steady aerodynamic model analytically calculates the aerodynamic loads by including four loading terms which originate from the wing's translation, rotation, their coupling and the addedmass effect. Based on the proposed FSI model, we optimize the twist of a rectangular wing by minimizing the power consumption during hovering flight. The power efficiency of optimized twistable and rigid wings is studied. Comparisons indicates that the optimized twistable wings exhibit power efficiencies close to the optimized rigid wings, unless the pitching amplitude at the wing root is limited. When the pitching amplitude at the root decreases by increasing the root stiffness, the optimized rigid wings need more power for hovering. However, with the help of wing twist, the power efficiencies of optimized twistable wings with a prescribed root stiffness are comparable with the twistable wings with an optimal root stiffness. This observation provides an explanation for the different levels of twist exhibited by insect wings. The high computational efficiency of the proposed FSI model allows further application to parametric studies and optimization of flapping wings. This will enhance the understanding of insect wing flexibility and help the design of flexible artificial wings for flapping wing micro air vehicles.

show abstract

“…Recently, a small-amplitude theory was proposed to model a flapping wing that pitches passively due to a combination of wing compliance, inertia, and fluid forces [13]. Furthermore, some numerical investigations were carried out to reveal the effects of flexibility on propulsion [14][15][16][17]. In addition, experiments were performed to understand the role of wing and fin flexibility in flapping locomotion [18,19].…”

Section: Introductionmentioning

confidence: 99%

Self-propulsion of a flapping flexible plate near the ground

et al. 2016

Self Cite

View full text Add to dashboard Cite

The self-propulsion of a three-dimensional flapping flexible plate near the ground is studied using an immersed boundary-lattice Boltzmann method for fluid flow and a finite-element method for plate motion. When the leading edge of the flexible plate is forced into a vertical oscillation near the ground, the entire plate moves freely due to the fluid-structure interaction. The mechanisms underlying the dynamics of the plate near the ground are elucidated. Based on the propulsive behaviors of the flapping plate, three distinct regimes due to the ground effect can be qualitatively identified. These regimes can be described briefly as the expensive, benefited, and uninfluenced propulsion regimes. The analysis of unsteady dynamics and plate deformation indicates that the ground effect becomes weaker for a more flexible plate. We have found that a suitable degree of flexibility can improve propulsion near the ground. The vortical structure around the plate and the pressure distribution on the plate are analyzed to understand propulsive behaviors. The results obtained in this study can provide some physical insights into the propulsive mechanisms of a flapping flexible plate near the ground.

show abstract

Propulsive performance of a passively flapping plate in a uniform flow

Cited by 6 publications

References 20 publications

Study on the Hydrodynamic Performance of Typical Underwater Bionic Foils with Spanwise Flexibility

Study on the Hydrodynamic Performance of Typical Underwater Bionic Foils with Spanwise Flexibility

An efficient fluid–structure interaction model for optimizing twistable flapping wings

Self-propulsion of a flapping flexible plate near the ground

Contact Info

Product

Resources

About